Browse Topic: Head injuries

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Summary of Poster Abstracts09-14-03-002010/26/2026
Fifteen research posters were prepared and presented by student authors. The posters covered a wide breadth of works-in-progress and recently completed projects. Topics included a variety of body regions and injury scenarios: Assessment of Layered Seat Cushion Configurations for Underbody Blast Protection Quantifying Head Impact Exposure in Collegiate 15s Rugby and Relationship to Clinical Measures Elderly Fatality in CIREN Cases: A Matched-Case Review The Relationship between Injury Risk for Child, Teen, and Adult Pedestrians in Collisions Preceded by PAEB Activation and PAEB Pulse Characteristics Quantifying Kinematic and Vibrational Responses in Hockey-Style Catcher’s Mask Incorporating Cortical Bone Property Variability into Simulations of Isolated Ribs under Anterior–Posterior Bending Lacrosse Ball Impacts on Women’s Headgear Mechanical Characterization of the Liver and Kidney: A Systematic Review Quantifying Changes in Mouthguard–Dentition Fit to Support Head Impact Measurement Validity Whole-Body MRI to Assess Perfusion Success and Soft Tissue Injuries in PMHS Subjected to High-Rate Loading Quantitative CT and MRI-Based Modeling Assessment of Spine Injury Risk Following Long-Duration Spaceflight An Investigation of Local Accelerator Pedal Geometry Effects on Ankle Motion How Do Different Human Body Models Affect Occupant Impact Responses and Restraint Design Optimizations in Frontal Crashes? The Potential Effects of Youth Hockey Helmet Shell Add-Ons Evaluation of Surrogate Soft Tissue Candidates for Biofidelity and Durability
Forman, Jason, Mueller, Becky
Influence of Blast Directionality, Intensity, and Combat Helmet Use on Head Surface Pressure Responses09-14-03-001710/26/2026
The widespread use of explosive weapons in recent military conflicts has contributed to an increased incidence of traumatic brain injuries. Although current infantry helmets provide effective protection against fragmentation, ballistic impact, and blunt trauma, they are not designed to mitigate primary blast loading. Previous studies suggest that blast waves may infiltrate the space between the head and helmet, leading to localized increases in pressure on the head surface, a phenomenon referred to as the underwash effect. However, experimental validation of the underwash effect remains limited, particularly for blast scenarios representative of buried-charge detonations, despite their potential to increase underwash-related loading across large regions of the cranial surface. This study experimentally evaluated the effects of combat helmet use, blast orientation, and blast intensity on head surface loading to assess helmet protective performance across various blast scenarios. A human surrogate headform instrumented with four flush-mounted pressure sensors was exposed to blast overpressures of approximately 16 and 24 psi using a large advanced blast simulator. Tests were conducted at 0° and 45° head orientations (rotation about the transverse axis), both with and without a combat helmet, with three repetitions per combination of experimental conditions. In the 0° orientation, helmet use reduced loading at the forehead and anterior head but increased loading at the posterior region. In the 45° orientation, helmet use led to increased peak pressure and total impulse at all measured locations. Increasing the blast intensity resulted in similar trends for both orientations and helmet conditions but with greater peak pressures and total impulses at each measured location. These findings suggest that certain blast orientations exacerbate the underwash effect and amplify cranial loading beneath the helmet. This work advances understanding of orientation-dependent blast loading, highlights limitations in current helmet performance, and offers guidance to support the development of future protective technologies.
Nelson, Allison J., Burt, Ethan T., Hamilton, Joseph M., Espinoza, Kenny J., Magallanes, Joseph, VandeVord, Pamela J.
Influence of Helmet Surface Protrusions on Youth Bicycle Helmet Impact Performance09-14-03-001910/26/2026
Youth bicycle helmet manufacturers often add shell protrusions to make helmets more attractive or fun for children, yet the safety implications of these features are not well understood. While prior work suggests protrusions may affect head impact kinematics, no study has evaluated their effectiveness in location-matched impacts between helmets with and without protrusions. Twelve youth bicycle helmet models, with protrusions intact and removed, underwent matched oblique impacts at three locations and 4.2 m/s to capture resulting peak linear acceleration (PLA) and peak rotational acceleration (PRA). A linear mixed model was used to quantify the effect of protrusion presence on PLA, PRA, and impact duration. The youth bicycle helmet models produced a wide range of kinematics. Protrusion presence had a strong effect on PLA, PRA, and impact duration. PLA averaged 103.0 ± 22.8 g for helmets with protrusions compared to 143.9 ± 21.4 g for helmets without protrusions, while PRA averaged 4432 ± 1570 rad/s2 for helmets with protrusions and 5177 ± 2110 rad/s2 for helmets without protrusions. These findings suggest that helmet protrusions can reduce peak head accelerations in youth bicycle helmet impacts.
Jung, Caitlyn, Stark, Nicole E.-P., Rowson, Steve
Letter from the Guest Editors09-14-03-000810/26/2026
Letter from the Guest Editors
Mueller, Becky, Forman, Jason
Behind-Helmet Blunt Trauma Deformation Geometry under Different Helmet Materials09-14-03-001610/26/2026
Modern combat helmets improve wearer survivability through preventing ballistic penetration via delamination or deformation of the shell material. However, this deformation may impinge upon the skull and present a risk of behind-helmet blunt trauma (BHBT). While legacy aramid helmets from the late 1970s–1980s inform current NIJ testing standards, the advent of lower areal density ultra-high molecular weight polyethylene (UHMWPE) and modern suspensions may incur unknown changes that present an unknown effect on BHBT risk. This study investigates whether current standards relying on a peak acceleration threshold and residual clay deformation may not reflect changes in deformation geometry seen in newer shell materials and suspension designs. Thirty-eight helmets categorized into three groups, older aramid, newer aramid (with new suspension), and prototype UHMWPE (with old suspension), were mounted on Hybrid III ATD head-necks and impacted on the temporal surface with 9 mm NATO projectiles at velocities between 388 and 482 m/s. Flash x-ray imaging captured deformation geometry. Deformations were digitized to measure maximum depth, volume, and surface area recruited. Multiple linear regression identified the influence of shell material and suspension on geometry. Results indicated that shell material significantly affected deformation volume and area (p < 0.05). Notably, UHMWPE exhibited a qualitatively more “pointed” deformation profile compared to aramid, recruiting material differently as depth increased. In contrast, suspension type and helmet design did not significantly influence deformation geometry. These findings suggest that the BHBT geometry in UHMWPE helmets differs fundamentally from aramid helmets. As UHMWPE helmets encounter higher-energy threats, current acceleration threshold or depth-based standards may not fully capture the risk of skull fracture. To future-proof helmet validation, testing standards should evolve beyond current standards to include area recruitment and other geometric measures.
Pang, Derek Y., Salzar, Rober S., Boggess, Brian M., Bass, Cameron R.
Deriving Representative Head-Impact Profiles in Contact Sports: A Shape-Based Clustering Approach09-14-03-001810/26/2026
Instrumented mouthguards (iMGs) capture thousands of head acceleration events in contact sports, though processing the data from these into meaningful information remains a challenge. To bridge this gap, we developed a principled clustering pipeline to extract concise kinematics that are representative of real-world impact scenarios. We evaluated six multivariate time-series distance metrics using k-medoids clustering and a dataset of 5149 impacts across three sports: mixed martial arts, boxing, and rugby union. Model performance was evaluated using a Coverage Quality Score (CQS), prioritizing reconstruction coverage and cluster separation. Joint Shape-Based Distance (SBD) significantly outperformed all other metrics, including Dynamic Time Warping (DTW), driven primarily by superior reconstruction coverage. The methodology yielded two complementary archetypes. First, a 36-impact canonical set provides distinct medoids representing core kinematic mechanisms; however, distributional checks confirm these medoids alone do not reproduce cohort severity distributions. To resolve this, we generated a second, extended impact set sampled proportionally within clusters along specific severity axes (e.g., peak acceleration and whole-brain strain). This targeted sampling recovers full severity-distribution fidelity using fewer than 150 impacts per dataset. Ultimately, this framework successfully distills large iMG datasets into manageable cohorts providing a scalable solution for assessment, experimental targets, and finite element simulations.
Koumantou, Eleni, Chan, Emily Yik Kwan, Jones, Chris M., Austin, Kieran, Loosemore, Mike, Ghajari, Mazdak
Relevant vehicle front-end components for pedestrian laboratory testing to address real-world pedestrian injuries when struck by passenger vehicles with high hood heights2026-22-00098/14/2026
In the United States, pedestrian deaths account for 18% of roadway fatalities and have increased 78% since their lowest point in 2009. U.S. consumers are increasingly purchasing larger vehicles that are responsible for a disproportionate number of pedestrian injuries. This study examined a dataset of pedestrians struck by passenger vehicles in Michigan from 2015 to 2024 to identify the unique characteristics of the tallest vehicles, large SUVs and pickups, which are contributing to increased injury. Vehicle height was categorized as the hood leading edge (HLE) height compared with the estimated pedestrian hip and waist heights from anthropometric measures. Maximum abbreviated injury scale and injury sources by body region were tabulated for three vehicle height categories. Typical kinematic patterns were observed for each relative height category and the corresponding injury frequency and impact locations. For vehicles with high hood heights, head and torso injuries were commonly from the front of the vehicle —the grille, headlights, and HLE. In contrast, head injuries sustained when pedestrians were struck by medium-height and short vehicles were primarily from the vehicle hood and windshields. Even among the tallest vehicles where the bumper was much higher than the pedestrian’s knee, leg injuries from the vehicle bumper and valance were frequent, suggesting that evaluating these vehicle components is also necessary to address lower extremity injuries. This study identified the unique pedestrian impact locations associated with the tallest vehicles, which can help guide vehicle designers when considering impact attenuation strategies to reduce injury in crashes with pedestrians.
Mueller, Becky, Jermakian, Jessica
Experimental Analysis of Human Head Dynamic Response and Injury under High-G Landing Shock2026-99-18617/17/2026
This study looks at how the human head reacts and gets injured during high-G landing impacts in spacecraft return capsules. We used a vertical drop tower system for the experiments. A standard crash test dummy, called the Hybrid III 50th, was used to imitate how astronauts sit during landing. We applied two common safety standards—the Head Injury Criterion (HIC) and the 3 ms cumulative acceleration rule—to measure head response under high-G impacts. The results show several things. First, head acceleration increases linearly as seat acceleration increases. Second, the peak total acceleration of the head is much higher than the seat acceleration. In particular, acceleration in the X and Z directions is much stronger than in the Y direction. Third, when seat acceleration went over 47.71 g, HIC exceeded the safe limit of 700, and the 3 ms head acceleration also passed the 80 g limit. This suggests that 40 g should be considered a safe upper limit for seat acceleration. This work provides experimental support for improving landing systems to protect astronauts’ heads during high-G impacts.
An, Hao, Wang, Yafeng, Guo, Yazhou
Comparison of Concussion Risk Functions Generated from Two Different Datasets2026-22-00046/11/2026
To estimate risk of concussion, risk functions based on injuries occurring in sports are often used. A range of datasets have been used to develop injury risk functions for concussion based on either global kinematics or tissue-level predictors. Two such datasets are one from American football, and another one from Australian football and rugby. These two datasets constitute the largest published collections of video-verified concussive cases in sports with known kinematics suitable for constructing risk functions. The objective of this study was to analyze the differences between two datasets of concussion for injury predictions to better understand the influence on injury risk functions. The kinematics were applied to the KTH head model and risk functions for different kinematic- and tissue-based predictors were developed and compared. The accuracy, sensitivity, specificity, and AUC were also compared. The two datasets evaluated in this study generated different risk curves. The datasets had some similarities such as having no significant difference in resultant linear acceleration, but also some differences, for example having a significant difference in resultant angular velocity. The Australian cases had relatively equally distributed major x-, y-, and z-components for angular velocity while the majority (59%) of the NFL cases had a major x-component (coronal plane rotation) representing more than 50% of the resultant. The y-component of the linear acceleration (lateral direction) was the major component in 64% of the Australian cases and 72% of the NFL cases. The two datasets, from Australian football/rugby, and American football, generated different injury risk curves with a lower 50% risk of concussion for the Australian dataset. This indicates that the choice of data as input for the development of injury risk functions is important. Therefore, it is necessary to improve methodology with focus on sampling methods and reliable/valid data collection.
Fahlstedt, Madelen, Meng, Shiyang, Patton, Declan, McIntosh, Andrew S., Kleiven, Svein
Traumatic Brain Injury in Vulnerable Road Users: Analysis of German In-Depth Crash Data to Inform Targeted Prevention2026-22-00035/28/2026
Road traffic crashes are a major cause of traumatic brain injury (TBI), particularly among vulnerable road users (VRUs). However, current injury prevention strategies often overlook the heterogeneity of TBI—which include various injury types and severities—leading to an oversimplified approach to evaluating helmets and safety systems in regulations and ratings. To identify priority TBI types and severities in VRUs and to inform targeted prevention strategies, the German In-Depth Accident Study database was analyzed and a pathoanatomic classification system, i.e., Abbreviated Injury Scale, was employed. AIS 2 (moderate) TBIs account for 70-80% of all brain injuries across VRU groups, nearly half of which are concussions. For helmeted cyclists, milder TBIs are at a greater percentage than for unhelmeted cyclists. These findings highlight the need for expanding prevention efforts to include AIS 2+ injuries. Key injury types observed include concussion (with and without loss of consciousness), skull base fracture, subdural hemorrhage, contusion and laceration. New mechanism-specific injury criteria may be needed to address these injuries. The strong similarity in injury type ranking among different road users (the Kendall’s tau values ranged from 0.90 to 0.93) suggests similar needs for injury prevention. A new brain injury assessment criterion may serve all road user types.
Meng, Shiyang, Schindler, Ron, Kleiven, Svein, Lubbe, Nils
Rear-Impact Crash Injury Patterns and Predictors: Insights from Contemporary CISS and CIREN Field Data09-14-01-00295/4/2026
The objective of this study was to investigate occupant injury patterns and predictors in rear-impact crashes using recent US field data. Cases were queried from the Crash Investigation Sampling System (CISS, 2017–2023) and the Crash Injury Research and Engineering Network (CIREN, 2017–2024), yielding 1923 front-row outboard occupants from 1533 crashes. Crash documentation and vehicle photographs were manually reviewed to classify seatback deformation magnitude and secondary impact severity. Multivariable logistic regression models estimated associations between occupant, vehicle, and crash characteristics and Abbreviated Injury Scale (AIS) ≥ 2 and AIS ≥ 3 injury outcomes across body regions. Sensitivity analyses included CISS-only, weighted, single-event, and interaction models. Thoracic injuries were further subdivided into skeletal and cardiopulmonary categories. Findings reflect associations within the pooled CISS + CIREN analytic sample rather than nationally representative injury rates. Seatback deformation and multievent crash classification are proxy measures and may introduce misclassification and residual confounding. A total of 188 occupants sustained AIS ≥ 2 injuries and 81 sustained AIS ≥ 3 injuries. Head injury was the most frequent AIS ≥ 2 outcome, while thoracic injury was the most frequent serious injury outcome, accounting for 60% of AIS ≥ 3 cases. Across AIS ≥ 2 and AIS ≥ 3 models, crash severity (delta-v) was the most consistent predictor of injury. Age was strongly associated with injury across most AIS ≥ 2 outcomes and several AIS ≥ 3 models, particularly for overall maximum Abbreviated Injury Scale (MAIS) and thoracic injury. Seatback deformation was associated with injury across multiple models after controlling for crash severity and occupant characteristics, with severe deformation showing stronger associations with AIS ≥ 3 outcomes. Unbelted status was associated with abdominal, pelvic, and lumbar spine injury. Female sex was associated with thoracic injury, primarily attributable to cardiopulmonary rather than skeletal injury. These findings highlight statistical associations between seatback deformation severity, restraint status, occupant characteristics, and injury outcomes in rear-impact crashes.
Lockerby, Jack, Rudd, Rodney
Front-Row Seatback Contact for Pediatric Occupants Seated in Rearward-Facing Infant Child Restraint Systems during Frontal Crashes09-14-01-00195/4/2026
Using a subset of the Transport Canada dataset of rearward-facing CRS in full-frontal rigid barrier vehicle tests, the aim of the current study was to evaluate CRS and/or ATD head contact with the front-row seatback and categorize the contribution to the peak ATD head acceleration. For 33 cases of ATDs seated in rearward-facing CRS models installed in the second-row outboard seats across 19 vehicle tests, high-speed video footage was analyzed to identify instances and timings of CRS and/or ATD head contact with the front-row seatback. The timing of contact was compared to the ATD head acceleration time history to identify instances of “contributory contact” with the front-row seatback, which was defined as contact occurring before the ATD head acceleration was within 10 g of the peak. ATD contributory contact cases involved both the ATD head and CRS contacting the front-row seat, whereas CRS contributory contact cases involved only the CRS, but not the ATD head, contacting the front-row seat. No contributory contact cases were those that involved either ATD or CRS contact with the front-row seatback, but the contact occurred after the time point associated with 10 g below the peak ATD head acceleration. No contact cases were those that did not involve either ATD or CRS contact with the front-row seatback. Contributory CRS and/or ATD contact with the front-row seatback was found to be associated with increased head injury risk. Therefore, the energy-absorbing properties of the CRS head restraint and/or front-row seatback are likely important considerations regarding frontal crash protection for rearward-facing pediatric second-row occupants. Impact velocity, location, and angle were able to be calculated for two cases that involved contributory ATD contact with the front-row seatback. Such data could be used as boundary conditions for physical testing of front-row seatbacks and computational modeling.
Patton, Declan A., Tang, Kathy, Tylko, Suzanne, Arbogast, Kristy B.
Characterization of Fatal Cyclist Collisions Involving Nine Vehicle Types Traveling at Low and High Speeds in Japan09-14-01-00055/4/2026
To reduce traffic fatalities through vehicle safety measures, particular attention must be given to cyclist-related fatalities. Clarifying the characteristics of hazardous events leading to cyclist fatalities, not only by vehicle speed range but also by vehicle type, is essential and should be based on analyses of real-world accident data. Accordingly, this study aimed to characterize fatal cyclist accidents involving vehicles traveling at low and high speeds in Japan. We used macro accident data from the Japanese Institute for Traffic Accident Research and Data Analysis covering the period from 2013 to 2022. Based on nine vehicle types, we investigated the effects of road type, vehicle behavior, and accident type on cyclist fatalities. Additionally, we identified the five most frequent accident scenarios separately for each low- and high-speed category. At signalized intersections, the proportions of cyclist fatalities involving vehicles traveling at low speeds were higher than those involving vehicles traveling at high speeds across all vehicle types. In contrast, on straight roads, the proportions at low speeds were lower than those at high speeds for all vehicle types. In the low-speed range, cyclist fatalities within the top five scenarios accounted for 65% of all fatalities, with the most frequent scenario occurring at signalized intersections during left-turn maneuvers, where heavy-duty trucks accounted for 86% of the fatalities. In the high-speed range, cyclist fatalities within the top five scenarios accounted for 71% of all fatalities. The most frequent high-speed scenario involved crossing collisions at unsignalized intersections when vehicles traveled straight, with light passenger cars and sedans accounting for 29% and 24% of the fatalities, respectively. These findings provide valuable insights for the development of targeted traffic safety regulations and vehicle technologies aimed at reducing vehicle–cyclist collisions across different speed ranges.
Matsui, Yasuhiro, Oikawa, Shoko
Effects of Vehicle Speed, Category, and Front-End Design on Full-Body Injury Risks of a Midsized Male Pedestrian09-14-01-00175/4/2026
This study investigated how vehicle front-end geometry, impact speed, and vehicle category influence injury risk to a midsize male pedestrian. Eighty-one generic vehicle (GV) models representing sedans, sport utility vehicles (SUVs), pickup trucks, and minivans sold in the United States were developed by morphing three base models using an automated pipeline. Front-end parameters that were varied included ground clearance (GC), bumper height (BH), hood leading-edge (HLE) height, hood length (HL), bumper lead angle (BLA), hood angle (HA), and windshield angle (WSA). Each vehicle impacted the Global Human Body Models Consortium 50th percentile male simplified pedestrian (GHBMC M50-PS) model at 30, 40, and 50 kph, totaling 243 simulations. Boundary conditions followed the European New Car Assessment Program (Euro NCAP) pedestrian test protocol. Thirty-five injury metrics were extracted across the head, neck, thorax, abdomen, pelvis, and lower extremities. Linear mixed-effects regression models assessed relationships between vehicle front-end geometry, impact speed, and injury outcomes, with predictor selection guided by principal component analysis (PCA) and collinearity diagnostics. Impact speed was the strongest predictor of injury severity across all body regions. GC and HLE height were also dominant predictors. Wrap-type trajectories were common at lower speeds and in SUVs, trucks, and minivans, while sedans and minivans showed roof vaulting at higher speeds. Head injury severity increased with speed and was influenced by HA and BLA. Minivans showed elevated brain injury criterion (BrIC) and cumulative strain damage measure (CSDM25) values, indicating increased diffuse brain injury risk. Trucks produced the highest thoracoabdominal injury metrics, which correlated with HL, HA, and HLE height. Sedans showed higher right-side (trailing leg) femur forces, slightly lower left-side femur forces than SUVs and minivans, and lowest tibia moments. Trucks had greater tibia bending moments, while SUVs and minivans had higher left femur moments compared to sedans. GC and impact speed exacerbated lower extremity injuries, varying by vehicle category. These effects are driven by geometry: Higher GC increases the unsupported span below the knee, promoting tibial bending, while lower HLE heights shift impact forces above the knee, elevating femur injury risk.
Poveda, Luis, Miller, Logan E., Edwards, Colin C., Pollock, Madeline, Armstrong, William M., Hsu, Fang-Chi, Gayzik, Scott F., Weaver, Ashley A., Stitzel, Joel D., Devane, Karan S.
Effects of Child Anthropometry, Seatback Angle, Seat Rotation Angle, Seatbelt Force Limiting, and Collision Type on Injury Risk of Child Occupants in Highly Automated Vehicles2026-01-05704/7/2026
This study aimed to evaluate the influence of child anthropometry, seating postures (recline and rotation), seatbelt force limiting, and frontal collision scenarios on the kinematic response and injury risk in highly automated vehicles. The TUST IBMs 6YO-O model was conducted the frontal collisions in sled tests. This simulation matrix includes five percentiles six-year-old occupants (P3, P25, P50, P75, and P97), three seatback angles (20°, 30°, and 45°), four seat rotation angles (0°, 90°, 180°, and 270°), three seatbelt force limiting (2.6 kN, 3.6 kN, and 4.6 kN), and three frontal collision types. Injury risks were assessed including the child occupant's head, neck, chest/abdomen, and lumbar region in each simulation (n=540). The results indicate that the child anthropometry, the seatback angle, and the seat rotation angle have a significant influence on the motion responses. Statistically significant differences between all the groups within each independent variable category were observed based on the analysis of variance. As the child dimension increases, the risk of head injury decreases showing by HIC15, while the risk of neck and lumbar injuries increases. As the seatback angle increases, biomechanical parameters of the head show an increasing trend. The risk of upper neck injury decreases, while the risk of lumbar injury decreases and then increases. As the seat rotation angle increases, the risks of head, neck, and chest injuries initially rise and subsequently decrease, while the risk of lumbar injury demonstrates a downward trend. Seatbelt force limiting exhibited a positive correlation with head, neck, and lumbar injury risks. Consequently, small percentile child experiences higher head loads in smart cockpits, with seatback angle and seat rotation angle being key factors contributing to child injuries. These findings highlight the critical need to address the vulnerability of smaller children in smart cockpits by adapting integrated active and passive safety systems to mitigate their injury risk.
Wang, Yanxin, Zhao, Hongqian, Li, Haiyan, He, Lijuan, Cui, Shihai, Lv, Wenle
A Study on the Relationship between Impact Conditions and Head Injury Criterion (HIC) in Powered-Two-Wheeler to Car Crashes2026-01-05714/7/2026
Road Traffic crash statistics highlight the importance of reducing fatalities among Powered-Two-Wheeler (PTW) riders, and suggest the necessity of a robust method to evaluate PTW crashworthiness performance. The objective of this study is to clarify the relationship between impact conditions and the Head Injury Criterion (HIC) to establish a fundamental basis for determining representative crash configurations for safety. A total of 1,272 PTW-front to car-side impact simulations were conducted by using production car and PTW models. HIC was used as a metric indicating likelihood of head injury. Velocities, impact angle, and impact locations were varied to create response surfaces. The surfaces were evaluated in terms of their accuracy in identifying the representative impact conditions. In addition, head trajectories were analyzed to clarify the kinematics until head impact. The Finite Element (FE) simulations produced the following findings. The HIC distribution by Head Impact Target can be categorized into 2 groups by the height of the car roof. Some of the low-roof car group results show a phenomenon of partial helmet removal, causing large variation in HIC. High HIC values are observed when the Y-direction displacement at the head impact is small. Structural stiffness and roof height may need to be considered when investigating a future test method that provides stable safety evaluation. These findings establish a fundamental basis for determining the representative crash scenario through an analysis of the relationship between crash conditions and the HIC.
Yanaoka, Toshiyuki, Gunji, Yasuaki, Zulkipli, Zarir Hafiz, Matsushita, Tetsuya, Carroll, Jolyon, Puthan, Pradeep, Mohd Faudzi, Siti Atiqah, D-Wing, Kak, Miyazaki, Yusuke
Machine Learning Based Meta-Analysis of IIHS Moderate Overlap Frontal Crash Test for Rear Seat Occupant Safety Performance2026-01-05794/7/2026
A machine learning (ML)-based meta-analysis was conducted to evaluate rear seat occupant safety performance in the Insurance Institute for Highway Safety (IIHS) Moderate Overlap Frontal (MOF) 2.0 crash test. ML models were trained on historical IIHS crash test data to predict rear passenger injury metrics using vehicle architecture, restraint system characteristics, crash pulse parameters, and vehicle kinematics as input features. The models demonstrated high predictive accuracy and were subsequently used in a Sobol sensitivity analysis to identify critical design parameters influencing injury outcomes. The analysis revealed that rear passenger injury metrics were most sensitive to restraint system parameters. Specifically, crash pulse magnitude was the dominant factor for head injury metrics, pretensioner activation time for neck tension force, and lap belt force for the Neck Injury Criterion (Nij). For chest-related metrics—sternum deflection, dynamic belt position, and maximum belt position—the initial belt position emerged as the most influential factor. This study demonstrates the potential of ML models to uncover dominant injury mechanisms and critical design parameters without explicitly encoding biomechanical knowledge. The findings also offer actionable insights to guide future vehicle safety design improvements for rear seat occupants.
Lalwala, Mitesh, Kim, Wonhee, Furton, Lisa, Song, Jay
Injury Risk Analysis of Occupant with Different Lower Limb Postures under the Frontal Impact Sled Conditions2026-01-05724/7/2026
To investigate the characteristics of injuries sustained by occupant with different lower limb postures under the frontal impact sled conditions. Using the finite element method a series of simulation analyses were conducted on THUMS (Total Human Model for Safety) AM50 human body model with four different postures, including standing posture, lower limb bent at 100°, 90°, and crossed forward-backward, under the frontal impact scenario at 56 km/h in this study. The simulation results indicated that the overall injury risk predicted by the THUMS AM50 huma body model with lower limb crossed forward-backward was higher than that predicted by the model with other postures. The values of injury criteria including of HIC (Head Injury Criterion), head resultant acceleration, and thoracic VC (Viscous Criterion) predicted by the THUMS AM50 huma body model with lower limb crossed forward-backward were highest in these series simulations. Also, the biomechanical responses, including stress or strain of thoracic/abdominal organs, pelvic cortical bone and knee ligaments, predicted by the THUMS AM50 huma body model with lower limb crossed forward-backward was higher than these predicted by the model with other postures.
Li, Dongqiang, jiang, Yejie, Tan, Chun, Li, Yanyan, Li, Yihui, Wu, Hequan, Jiang, Binhui, Zhu, Feng
CAE Acceleration with Machine Learning for Results Prediction2026-01-04884/7/2026
Industries are following a tedious product development cycle for developing their product. In product development major steps includes design ideas, Drawings, CAD, CAE, Testing and design improvement cycle. This is a monotonous process and takes time which impacts on its time to deliver product and cost on development. Now a days industries are fast growing and targeting to reduce development cycle time and cost. AI&ML is impacting almost all areas in the industry and significantly reducing efforts time and cost. To make use of AI&ML in CAE, Altair Physics AI is an effective tool. To ensure the design of product traditional way is to develop a CAD of the product, develop, perform CAE and analyze performance. If we consider CAE procedure it is time consuming process which includes FEA model build, applying boundary conditions, running simulation and analyzing results which could take minutes to hours. By using ML with Physics AI we can make predictions on new design of the product in seconds and significantly save time and cost. To demonstrate the CAE acceleration process with physic AI we have solved two case studies. The first case study is head impact on hood where ML tool will predict deformation contour of the hood, acceleration and displacement curve of the impactor. The second case study is Tube crush analysis where prediction of tube deformation pattern, force and energy curve for different tube length and impact velocity is carried out. For both Case studies we have used TCS inhouse data to train test and prediction of the ML model. For Head impact case study, it gives lower training loss with more than 90 percent prediction accuracy. Similarly for tube crush study it gives good accuracy and predicts comparable behavior patten with CAE results. Physic AI ML tool accelerates the design and development cycle and can be utilized in different product development. Implementation of ML accelerates the CAE process in design and development of products. It saves a lot of time in multiple design iteration study. Similar method can be implemented for different CAE cases.
Dangare, Anand Manohar, Kulkarni, Mandar
Jute-Polyester Trim as a Novel Vehicle Upper Interior Head Impact Safety Countermeasure2026-01-05674/7/2026
A significant fraction of annual global human mortality is caused by severe head injuries resulting from vehicle crashes. In order to ensure upper interior head impact safety in vehicles, stiff upper body pillars are covered with plastic trims often along with internal countermeasures such as fin-type monolithic ribs. In the study being reported here, a consistent Computer-Aided Engineering (CAE) procedure employing explicit nonlinear finite element analysis has been demonstrated for predicting headform impact safety of a steel A-pillar component covered with a novel jute-polyester trim. Using simulation as mentioned combined judiciously with test data and physical reasoning, a number of jute-polyester trim configurations are considered by varying the number of jute plies, and packaging space between trim and A-pillar inner panel. Additionally, jute-polyester trims with internal ribs are considered. The current study reinforces the potential of a jute polymer composite as a vehicle head impact safety countermeasure.
Karthika, M R, Deb, Anindya, Zhu, Feng
Development of Automotive Hood Using Multi-Material Double Injection Molding – An Overview2026-01-04764/7/2026
This paper presents the multidisciplinary development of a hybrid automotive hood manufactured using double-shot injection molding with overmolded brackets. Conventional steel and aluminum hoods, while structurally reliable, pose challenges in terms of weight reduction, pedestrian head protection, and manufacturing cost. Composite and thermoplastic alternatives supported by computational analysis and advanced molding processes provide opportunities to address these challenges. Finite element analysis (FEA) was employed to evaluate torsional and bending stiffness, locking load, and crashworthiness, while pedestrian headform simulations following ECE R127 and EEVC WG17 guidelines were conducted to assess compliance with safety regulations. Adhesion and bonding strength of overmolded polymer–polymer interfaces were studied to validate manufacturing feasibility. Results confirm that hybrid hoods fabricated using multi-material double-shot molding can achieve weight reductions of up to 30% compared with steel, maintain structural stiffness equivalent to aluminum, meet head injury criterion (HIC) thresholds, and reduce assembly complexity by consolidating brackets and reinforcements into a single integrated structure.
Ganesan, Karthikeyan, Seok, Sang Ho, Jo, Hyoung Han
Effective Design Method for Lightweight Suite of Seats Considering Crashworthiness and Cost2026-01-04934/7/2026
This paper presents a methodology for designing and evaluating lightweight, crashworthy aircraft seats that meet 21g crash safety standards and injury criteria. Four seat classes—double economy, single economy, premium economy, and business—were developed using a modular design strategy focused on part commonality (family of parts) and manufacturability. A shared family of structural components was implemented across all seat types, with dimensional modifications applied only, when necessary, due to differences in seat width or height. In such cases, the same material systems and design principles were used to ensure consistency and reduce manufacturing complexity. The designs were evaluated using finite element simulations to verify performance under aerospace crash conditions. Each seat configuration was validated against regulatory crashworthiness criteria and injury thresholds, including pelvic, lumbar, and femur compressive forces, as well as head injury criteria (HIC) values. The final designs successfully passed all crash and most injury thresholds, achieving regulatory compliance while maintaining a lightweight structure. This marked a significant improvement over a baseline seat configuration that failed to meet crash or injury requirements. By combining modularity with performance-driven design, this approach delivers a flexible and manufacturable seat family that balances safety, weight, and cost. The methodology offers broader applicability for occupant protection systems in automotive and aerospace domains, where lightweighting and regulatory compliance remain critical design challenges.
Gray, Savannah, Orr, Mathew, Shi, Yifan, Park, Taeil, Lee, Jake, Wotten, Erik, LeFrancois, Richard, Huang, Yuhao, Patel, Anuj, Kim, Hansu, Burns, Nicholas, Jalayer, Shayan, Grant, Robert, Kok, Leo, Hansen, Eric, Kim, Il Yong
Use Inertial Sliding of Reclined Seat to Enhance Occupant Retention under Rear-End Crash2026-01-05634/7/2026
Autonomous vehicles may attract more passengers to recline their seat for comfort. However, under severe rear-end crashes and large reclining angle, the backward inertia could completely throw occupant out of seat. Even if the occupant body can be restrained by seatbelt, the occupant’s head could slide out of the head restraint area. Any of these situations may cause severe injuries. To address this safety concern, we developed a sliding seat system designed to enhance occupant retention. Activated by impact inertia of rear-end collision, the system allows the seat sliding backward along its track in a controlled manner, and the sliding stroke is accompanied by a restraint force and absorbs some amount of kinetic energy during the sliding. Thus, occupant retention can be enhanced, and injury risks of head and neck can be reduced. To demonstrate this concept, we built a MADYMO model and conducted a parametric analysis. The model includes a 50th percentile human model, a vehicle seat, and a seat-mounted three-point seatbelt. Under 50 km/h rear-impact load, we evaluated occupant kinematics and critical injury metrics of 45o reclined posture. The relative displacement between occupant pelvis and seatback was used to measure the distance that occupant slides backward, which is a metric for occupant retention. The results have shown that seat sliding distance is the most critical factor for occupant retention, and the longer the sliding distance, the greater the retention effect and the lower the injury risk. In a typical scenario when 200 mm of sliding distance is available for sliding, compared to traditional fixed seat (no sliding allowed), the occupant displacement is reduced by 45%, the Head Injury Criterion value is reduced by 55%, and the Neck Injury Criterion value is decreased by 66%. For vehicle seat design, using the sliding seat system may help off-load the burden of enhancing recliner stiffness, a critical component for maintaining seatback stiffness level in rear-end collisions.
Dai, Rui, Zhou, Qing, Puyuan, Tan, Shen, Wenxuan
Characterization and Material Card Calibration of PU Foam Under Various Strain Rates for Crash Simulation2026-26-04641/16/2026
PU foam shows a excellent energy absorbing dissipation properties during impact load so it commonly used in car seats, cabin and crash protection system. Specifically, in vehicle seats PU foams play a critical role in protecting occupants during crash scenarios by absorbing energy, distributing forces, and improving seatbelt performance, additionally providing countermeasures for head impact protection. The movement of the seat and the direction of the force during crash testing are highly unpredictable. The material behaviour of PU foam is captured using an isotropic, hyper-elasticity-based constitutive model available in LS-DYNA through MAT_083. This model is designed to take into account the foam's compressibility, sensitivity to strain rates, low Poisson's ratio, and hysteresis. The characterization of a PU foam with a nominal density of 65 kg/m3 was performed using quasi-static compressive testing of 0.01/s and dynamic compressive testing of 1/s,13/s, 120/s, as well as a quasi-static tensile test of 0.01/s. The material response data were used to calibrate the LS-DYNA foam model MAT-FU CHANG FOAM MAT-083. Calibration of the LS-DYNA material card (*MAT_FU_CHAN_FOAM MAT-083) was performed using coupon-level test data. The goal was to accurately simulate the foam's behaviour under varying strain rate conditions and extract the deformation pattern. Finally, the simulations were conducted with the same geometry and loading conditions as the experimental setup. The performance of the material card was validated by comparing simulation results with experimental data, demonstrating its ability to replicate foam behaviour under crash conditions.
Gaurav, Ashish Kumar, Krishnamoorthy, Kunju, Varatharajan, Senthilkumaran
Jerk Evaluation Criteria for Pedestrian Head Impact on Windshield and Technological Requirement to Meet the Criteria2026-26-00231/16/2026
The safety of vulnerable road users, particularly pedestrians, cyclists, and motorcyclists, is a paramount concern in automotive design and regulation. In India, the situation is particularly alarming, with pedestrians being the second highest victims of road accidents, as evidenced by over 32,825 reported pedestrian accidents and 4,836 cyclist fatalities in 2022, excluding two-wheeler motorcyclists. On a global scale, the prevalence of such incidents has prompted European countries to introduce new regulatory requirements, such as ECE R127.03. This regulation encompasses the evaluation of pedestrian head form impacts on windshields, assessing the typical behavior of glass through jerk criteria following initial contact, in conjunction with the existing Head Injury Criterion (HIC) evaluation for pedestrian head forms. These criteria’s are meticulously designed to ensure that both acceleration and jerk remain within safe limits to reduce the severe risk of severe injury to head of vulnerable road users, thereby providing a more comprehensive approach to pedestrian protection. This Paper focuses into a detailed understanding of the new evaluation criteria for head impact on windshield by describing its benefits and principal design requirements for vehicles to meet these criteria. To comprehend these fundamental design requirements, an initial study was conducted on existing vehicles through physical testing, simulation, and correlation. Detailed simulations were performed, and the correlated model was subsequently utilized to identify the design modifications necessary to meet these criteria. Through an exhaustive analysis of test data and regulatory standards, this paper explores the effect of head impact on windshield of vehicle. The findings underscore the importance of optimizing windshield materials and structures to achieve the desired behavior. This research contributes to the ongoing efforts to enhance the safety of vulnerable road users and provides valuable insights for automotive manufacturers in their approach to meeting windshield requirements and developing safer vehicles in collaboration with regulatory bodies.
Kumar, Ritik, A, Rajesh
Geometrical Assessment of the Curtain Airbag Coverage in Indian Passenger Vehicles2026-26-00211/16/2026
Curtain airbags are the most effective protective systems to prevent severe/fatal head injuries in side collisions with narrow objects such as poles or trees. One of the important parameters of curtain airbags is the inflated zone i.e. the coverage area of the airbag, which decides the extent of head protection for occupants with different anthropometries in different seating rows. EuroNCAP first introduced the concept of Head Protection Device Assessment (HPDA) in 2015., In addition to the performance requirements in the dynamic test, EuroNCAP started assessing the deployed curtain airbag/s for its area coverage and verification of inflated zones for various anthropometries over occupant rows. In India, there is now a near total adoption of curtain airbags as standard fitment by the OEMs. Further, introduction of Bharat NCAP (BNCAP), a Perpendicular Pole Side Impact test is conducted for assessing the effectiveness of curtain airbags in a dynamic test, but currently, does not perform the HPD assessment. The paper studies the Head Protection Device/Curtain Airbags offered in Passenger Vehicles in India w.r.t. the Head Protection Device Geometric Assessment (HPDA). This assessment analyses the effectiveness of curtain airbags present in Indian passenger vehicles for protection of occupants of different anthropometries. The study is conducted on the vehicles that have been tested at ARAI and are also currently under sale in the Indian market.
Jaju, Divyan, Kulkarni, Dileep, Mahajan, Rahul
Enhancing Pedestrian Safety: LIDAR-Based Deployment of Front LID/Bonnet and Airbag Systems in Heavy Commercial Vehicles During Low-Speed Collisions2026-26-00061/16/2026
As urban population continues to grow, the safety of Vulnerable Road Users (VRUs) particularly in the presence of Heavy Good Vehicles (HGVs) has emerged as a critical concern. Research indicates that VRUs are at a 50% higher risk of fatal injury in collisions involving HGVs compared to passenger cars. To address this issue, this study proposes a novel pedestrian protection system that integrates LiDAR (Light Detection and Ranging) technology with a reusable airbag system to mitigate the severity of collisions. The proposed solution adopts a twofold approach for enhancing VRU protection in scenarios involving HGVs. In both approaches, LiDAR sensors are used to generate a real-time 3D model of the vehicle’s surroundings, enabling accurate VRU detection and predictive collision analysis. Scenario 1: When vehicle speed exceeds the first threshold and a collision is unavoidable, the onboard ECU activates front lid actuators, extending the vehicle's front lid which can be retracted back to its original position manually. Scenario 2: If vehicle speed exceeds a second, higher threshold, the system not only actuates the front lid but also deploys a non-pyrotechnic reusable airbag using compressed air and turbojet canisters. The extended front lid creates a space between the VRU’s head and the vehicle's hard structures, managing energies and reducing the risk of severe body injuries. The reusable airbag, covering the front lid’s corners, adds an additional cushioning effect at higher speeds. Headform impact simulations conducted on the truck front demonstrated the effectiveness of the proposed active front-lid mechanism. Six impact locations were evaluated using an LSTC® pedestrian headform, and the deployed front-lid configuration consistently showed notable reductions in Head Injury Criterion (HIC) values compared to the undeployed state. In particular, the additional deformation space created during deployment significantly reduced the severity of head impact with the underlying hard structures showing improvement in the performance. By combining advanced sensing with active impact mitigation technologies, this system offers a proactive, sustainable solution to enhance VRU safety in urban environment. The integration of LiDAR-equipped HGVs with reusable airbags represents a significant step forward in reducing traffic-related VRU injuries and fatalities.
Patil, Uday, Sriharsha, Viswanath, Pillai, Rajiv
Rear-Facing Infant Seat Structural Integrity and Crashworthiness under Front Seatback Loading in Rear-Impact Collisions2026-26-05541/16/2026
Rear-facing infant seats that are positioned behind front outboard vehicle seats are at risk of being compromised by the rearward yielding of occupied front seat seatbacks during rear-impact collisions. This movement can cause the plastic shell of the infant seat to collapse and deform, increasing the risk of head injuries to the infant. Current designs of rear-facing infant seats typically do not consider the loading effects from the front seatback during rear-impact situations, which results in weak and collapsible shell structures. Moreover, regulatory compliance tests, such as FMVSS 213, do not include assessments of rear-facing infant seats under realistic rear-impact conditions. as the bench used for the regulatory test lacks realistic vehicle interior components. This study emphasizes the need for revised testing methodologies that employ sled tests with realistic seatback intrusion conditions to facilitate the development of improved infant seat designs. Research shows that rear-facing infant seats designed for real-world loading conditions can improve safety and injury outcomes for infants in severe rear-impact collisions in the presence of front-occupied seats.
Thorbole, Chandrashekhar
Occupant Kinematics and Injuries during High Speed Side Impacts: An Analysis of ARAI Data 2016-20242026-26-00271/16/2026
The objective of the present study is to examine trends in occupant kinematics and injuries during side impact tests carried out on vehicle models over the period of time. Head, shoulder, torso, spine, and pelvis kinematic responses are analysed for driver dummy in high speed side impacts for vehicle model years, MY2016-2024. Side impact test data from the tests conducted at The Automotive Research Association of India (ARAI) is examined for MY2016-2024. The test procedure is as specified in AIS099 or UNECE R95, wherein a 950kg moving deformable barrier (MDB) impacts the side of stationary vehicle at 50km/hr. An Instrumented 50th percentile male EUROSID-2 Anthropomorphic Test Device is positioned in the driver seat on the impacting side. Occupant kinematic data, including head accelerations, Head Injury Criterion (HIC15), Torso deflections at thorax and abdominal ribs, spine accelerations at T12 vertebra, and pelvis accelerations are evaluated and compared. The “peak” and “time to- peak” responses are compared across different vehicle model years. The effect of delta-V, vehicle MY, on occupant kinematics is examined. For different vehicle delta V, MY2016-2020 demonstrated higher average peak kinematic responses compared to the MY2020-2024. The present study enhances the existing database of occupant kinematics in side impacts. A general trend of reduction in occupant kinematics and risks for injury is observed in vehicle models over the past decade.
Mishra, Satish, Borse, Tanmay, Kulkarni, Dileep, Mahajan, Rahul
Adaptive Restraints for Equitable Protection2026-26-00151/16/2026
Real-world crashes involve diverse occupants, but traditional restraint systems are designed for a limited range of body types considering the applicable regulations and protocols. While conventional restraints are effective for homogeneous occupant profiles, these systems often underperform in real-world scenarios with diverse demographics, including variations in age, gender, and body morphology. This study addresses this critical gap by evaluating adaptive restraint systems aligned with the forthcoming EURO NCAP 2026 protocols, which emphasize real-world crash diversity and occupant type. Through digital studies of frontal impact scenarios, we analyze biomechanical responses using adaptive restraints across varied occupant demographics, focusing on head and chest injury (e.g., Chest Compression Criterion [CC]). This study used a Design of Experiments (DOE) approach to optimize occupant protection by timing the actuating of these adaptive systems. The results indicate that activating adaptive seatbelts and airbags before reaching peak chest and pelvis accelerations can help reduce injuries. The study suggests a rule-based framework for adaptive restraints, demonstrating that injury optimization correlates strongly with time control of restraint parameters. These insights advance the development of occupant-centric safety systems, offering scalable solutions for emerging regulatory standards and enhancing protection for underrepresented demographics in vehicular safety engineering.
satija, Anshul, Suryawanshi, Yuvraj, Chavan, Avinash, Rao, Guruprakash
Upper Body Robotic ExoskeletonTBMG-5412311/1/2025
Innovators at the NASA Johnson Space Center have developed a soft, wearable, robotic upper limb exoskeleton garment designed to actively control the shoulder and elbow, both positioning the limb in specific orientations and commanding the limb through desired motions. The invention was developed to provide effective upper extremity motor rehabilitation for patients with neurological impairments (e.g., traumatic brain injury, stroke).
Research and Analysis on Airbag Dangerous Deployment Evaluation Based on 2024 Version C-NCAP2025-99-007310/17/2025
Research on the subjective items of airbag dangerous deployment in the 2024 version of C-NCAP regulations, which includes two aspects: the action of the airbag sweeping over the face and the speed of airbag deployment. This article starts from other aspects. On the one hand, when examining the action of airbags sweeping over the face, it is necessary to consider the acceleration index. Based on the head injury index of the front dummy in collision in C-NCAP, the injury index of face - sweeping risk is defined; On the other hand, the force level of facial injury should also be examined, and the definition and experimental methods should be discussed based on the force level that the head can withstand. Added airbag deployment hazard assessment for the HIII 5 female dummy.
Tian, Wei, Xue, Kaile, Wang, Qinggui
Traumatic Head and Brain Injuries in Helmeted Motorcycle Crashes2025-22-00066/27/2025
This study presents an analysis of 364 motorcycle helmet impact tests, including standard certified full-face, open-face, and half-helmets, as well as non-certified (novelty) helmet designs. Two advanced motorcycle helmet designs that incorporate technologies intended to mitigate the risk of rotational brain injuries (rTBI) were included in this study. Results were compared to 80 unprotected tests using an instrumented 50th percentile Hybrid III head form and neck at impact speeds ranging from 6 to 18 m/s (13 to 40 mph). Results show that, on average, the Head Injury Criterion (HIC) was reduced by 92 percent across certified helmets, compared to the unhelmeted condition, indicating substantial protection against focal head and brain injuries. However, findings indicate that standard motorcycle helmets increase the risk of AIS 2 to 5 rotational brain injuries (rTBI) by an average of 30 percent compared to the unprotected condition, due to the increased rotational inertia generated by the added size and weight of the helmet. Advanced helmets performed, on average, about 5 percent better than standard certified helmets. Non-certified or novelty helmets offer inadequate protection against focal head and brain injuries, though they may offer some insight into rTBI protection. The findings of this study also indicate a critical methodological deficiency in the oblique impact tests utilized in revised motorcycle helmet standards, including ECE 22.06, Snell M2025, and FRHPe-02, which fail to correctly assess rTBI risk. This paper provides recommendations for enhancing motorcycle helmet design to improve protection against rotational traumatic brain injuries.
Lloyd, John
Assessment of the Skull Fracture Prediction Capability of Finite Element Head Models2025-22-00056/16/2025
The development of drones has raised questions about their safety in case of high-speed impacts with the head. This has been recently studied with dummies, postmortem human surrogates and numerical models but questions are still open regarding the transfer of skull fracture tolerance and procedures from road safety to drone impacts. This study aimed to assess the performance of an existing head FE model (GHBMC M50-O v6.0) in terms of response and fracture prediction using a wide range of impact conditions from the literature (low and high-speed, rigid and deformable impactors, drones). The fracture prediction capability was assessed using 156 load cases, including 18 high speed tests and 19 tests for which subject specific models were built. The GHBMC model was found to overpredict peak forces, especially for rigid impactors and fracture cases. However, the model captured the head accelerations tendencies for drone impacts. The formulation of bone elements, the failure representation and the scalp material properties were found of interest for future investigation. The model still predicted a sizable proportion of skull fractures. With failure enabled, it reached a sensitivity of 86.6% and a specificity of 82.0% (n=156). With failure disabled, risk curves with a rating of good according to ISO/TS 18506:2014 were developed using the second principal strain in the outer table cortical solid elements.
Pozzi, Clément, Gardegaront, Marc, Allegre, Lucille, Beillas, Philippe
Head Accelerations and Concussion Risks in Low-to-Moderate–Speed Rear-End Collisions2025-01-50416/10/2025
Recent studies have investigated head injury metrics, including mild traumatic brain injury (mTBI), or concussion risks, in low- to moderate-speed rear-end collisions, with linear and angular head accelerations contributing to the risk of developing a concussion. The present study analyzes head acceleration values in rear-end collisions at an impact severity of 5–30 km/h delta-V. Biomechanical data was obtained from HIII 50th percentile male anthropomorphic test devices (ATDs) seated in the target subject vehicles and utilizing safety restraints and head rests. Concussion risks were calculated from resultant linear and angular head accelerations recorded in the ATDs, and a linear regression model was used to determine what, if any, relationship existed between these head injury metrics and impact severity. The results indicate that there is a significant and positive relationship between head acceleration metrics and impact severity, particularly in the sagittal plane, with F-values < 0.05. Additionally, there is a positive relationship between concussion risks and impact severity, but results also determine that the concussion risks are less than 0.1% and indistinguishable from 0 at this range of impact severity. An outlier test that included head impact with a rear-seated passenger ATD yielded a less than 2% risk of sustaining a concussion. It is expected that the results of this study will aid in accident reconstruction and biomechanical analysis for restrained occupants involved in low- to moderate-speed rear-end collisions.
Garcia, Beatriz, Emanet, Hatice Seyda, Hoffman, Austin
Proposed Reformulation of Brain Injury Criteria (BrIC) Using Head Rotation-Induced Brain Injury Thresholds Simulated and Derived Directly from A Subhuman Primate Finite Element Model2025-22-00035/13/2025
Recent studies have found that Brain Injury Criteria (BrIC) grossly overpredicts instances of real-world, severe traumatic brain injury (TBI). However, as it stands, BrIC is the leading candidate for a rotational head kinematics-based brain injury criteria for use in automotive regulation and general safety standards. This study attempts to understand why BrIC overpredicts the likelihood of brain injury by presenting a comprehensive analysis of live primate head impact experiments conducted by Stalnaker et al. (1977) and the University of Pennsylvania before applying these injurious conditions to a finite element (FE) monkey model. Data collection included a thorough analysis and digitization of the head impact dynamics and resulting pathology reports from Stalnaker et al. (1977) as well as a representative reconstruction of the Penn II baboon diffuse axonal injury (DAI) model. Computational modeling techniques were employed on a FE Rhesus monkey model, first introduced by Arora et al. (2019), to derive risk related brain tissue strain thresholds from the laboratory data. The existing critical velocities proposed for BrIC were then scaled until the target strain level associated with each severity level of diffuse brain injury was reproduced in the FE model of the human brain. Overall, this study provides a comprehensive understanding of these two historical non-human primates (NHP) models and predicts a strain based diffuse tissue injury threshold (MPS99.9) of 1.0 and 1.6 for concussion (mild TBI) and DAI (severe TBI), respectively. The findings indicate scale factors of 1.6 to 5.9 times the original BrIC critical velocities, depending on the loading duration, are required to predict severe (AIS 4+) diffuse brain injury. These results allude to a necessity for including angular acceleration and duration as kinematic parameters in an injury criterion that can accurately predict real-world, diffuse brain injuries. This study also attempts to evaluate and recommend a methodology for post-processing strain parameters produced by head models, settling on the use of MPS99.9 and CSDM50.
Demma, Dominic R., Tao, Ying, Zhang, Liying, Prasad, Priya
Lattice Based Localized Energy Absorber for Improved Vulnerable Road User Performance for a Vehicle2025-01-87234/1/2025
A passenger vehicle hood is designed to meet Vulnerable Road User (VRU) regulatory requirements and consumer metric targets. Generally, hood inner design and its reinforcements, along with deformable space available under the hood are the main enablers to meet the Head Impact performance targets. However, cross functional balancing requirements, such as hood stiffness and packaging space constraints, can lead to higher Head Injury Criteria (HIC15) scores, particularly when secondary impacts are present. In such cases, a localized energy absorber is utilized to absorb the impact energy to reduce HIC within the target value. The current localized energy absorber solutions include the usage of flexible metal brackets, plastic absorbers etc. which have limited energy absorbing capacity and tuning capability. This paper focuses on usage of a novel 3D printed energy absorbers, based on various kinds of lattice structures. These absorbers are either sandwiched between the inner and the outer hood or are integrated directly with under hood parts such as shock tower or headlamp bolt locations to mitigate high HIC values. The work focuses on virtual evaluation of Nylon-12 3D printed lattice designs, based on Body Centered Cubic (BCC) and Kelvin Lattice, for VRU energy management. These optimized lattice-based designs are shown to provide significant performance improvement over conventional energy absorbers. As 3D printing can support manufacturing of complex shapes, the lattice-based energy absorbers can be tuned easily to achieve optimal performance. Technological advancements in 3D printing make these solutions cost effective and easier to implement.
Kinila, Vivekananda, Agarwal, Varun, V S, Rajamanickam, Tripathy, Biswajit, Gupta, Vishal
Predicting Head Injury Criterion in Real-World Frontal Impacts2025-01-87094/1/2025
Research on modeling head injury metrics and head acceleration waveforms from real-world collisions has been limited compared to vehicle crash pulses. Prior studies have used rectangular, triangular, polynomial, half-sine, and haversine pulse functions to model vehicle crash pulses and have employed more complex approximations for head injury metrics. This study aimed to develop a method to predict 15 ms Head Injury Criterion (HIC15) in frontal passenger vehicle impacts using these simple pulse functions, where only occupant peak head acceleration and head impact duration are known. Vehicle crash tests from the New Car Assessment Program (NCAP) were selected for frontal impacts that included driver occupants. Head acceleration and shoulder belt load channels of Hybrid III 50th percentile male anthropomorphic test devices were collected and separated for training a set of ratios and testing their performance. Rectangular, triangular, quadratic, half-sine, and haversine pulse functions were modeled using peak head acceleration and the duration of significant head acceleration from each ‘training’ NCAP crash test. Duration ratios were values calculated to scale each pulse function to predict the same HIC15 as the driver’s experimental acceleration-time curve. Duration ratios were evaluated on each ‘testing’ NCAP crash test by comparing the HIC15 predicted by each scaled pulse function against the driver’s HIC15. All five pulse functions generated from the model ‘training’ NCAP tests had significantly different duration ratios. There were no significant differences in predicted HIC15 to the driver’s HIC15 from the model ‘testing’ NCAP tests for all pulse functions. Findings indicate that applying the presented duration ratios to the five pulse functions can effectively predict HIC15 in frontal crashes similar to NCAP tests, making them useful tools when only peak head acceleration and head impact duration are known. This work will help biomechanical safety experts evaluate head injury risk when real-time occupant kinematics are not available.
Westrom, Clyde, Tanczos, Rachel, Adanty, Kevin, Shimada, Sean
Biofidelity Evaluation of AC-HUMs Pedestrian Model Based on Generic Sedan Buck Model2025-01-87434/1/2025
Objective: This study aims to evaluate the biofidelity of the Advanced Chinese Human Body Model (AC-HUMs) by utilizing a generic sedan buck model and post-mortem human surrogates (PMHS) test data. Methods: The boundary conditions of the simulation were derived from the PMHS test with the buck vehicle. The methodology involved the pose adjustment of the upper and lower extremities of AC-HUMs, executed through a pre-simulation approach. Subsequently, a 200 milliseconds whole body pedestrian crash simulation was conducted using the buck vehicle and the AC-HUMs pedestrian model. The trajectories of AC-HUMs during the period from initial position to head impact were recorded, including the Head CG, T1, T8 and pelvis. Based on the knee joint, the corridors of trajectories from the PMHS test were scaled to match the Chinese 50th percentile male to evaluate the biofidelity of AC-HUMs's kinematic response. Furthermore, the biomechanical responses were compared with the PMHS tests, including injuries of chest and lower extremities. This comparison comprehensively evaluated the injury prediction capability of the AC-HUMs pedestrian model under whole-body pedestrian collision scenarios. Conclusion: The results indicate that the trajectories of the four markers on the AC-HUMs pedestrian model were all within the scaled trajectory corridors, confirming that the model exhibits good biofidelity. The results reconstructed similar ligament rupture scenarios (left LCL, right ACL, and MCL) as well as partial rib injuries. The findings also revealed potential biofidelity issues in the neck, ribs, knee joint, and tibia regions of the AC-HUMs model. Despite these challenges, the AC-HUMs pedestrian model demonstrates good biofidelity in motion trajectories and possesses the ability to replicate biomechanical responses. This indicates that the AC-HUMs model has significant potential for virtual vehicle safety assessments in China, positioning it as a promising tool for this purpose.
Qian, Jiaqi, Wang, Qiang, Liu, Yu, Wu, Xiaofan, Huida, Zhang, Bai, Zhonghao
A Study on Affections of Different Skull-Brain Interface Modeling Approaches on Intracranial Responses in Finite Element Analysis2025-01-87334/1/2025
The skull-brain interface is structurally complex, and various simplification methods have been employed in existing head models to simulate the interaction between the skull and the brain. The modeling approach of the skull-brain interface determines how loads are transmitted to the interior, which is critical for accurately simulating head injuries. Thus, understanding the impact of current skull-brain interface modeling approaches on intracranial simulation results is significant. This study aims to explore the influence of different skull-brain interface modeling methods on the results of finite element models during the development of Advanced Chinese Human Body Models (AC-HUMs) based on the LS-DYNA solver. By comparing the responses of rigidly bonded connections (tied Contact), failure-allowing bonded contacts (tiebreak Contact), shared nodes, and arbitrary Lagrangian-Eulerian (ALE) methods under the Nahum 37 test load conditions, the study analyzes the effects of different modeling methods on pressure and deformation trends. Additionally, varying the failure values of tiebreak contact allows for the calculation of intracranial pressure responses under the same load conditions, revealing the influence of failure values on intracranial pressure responses. The results indicate that only the tiebreak model can simulate the transition from negative to positive pressure observed in experimental results, with significant variations in simulation outcomes corresponding to changes in failure values. This research provides a reference for the selection and optimization of finite element head modeling methods. Tiebreak contact is a better choice if the interface tearing effect needs to be modelled under linear impact conditions; Tied contact and shared nodes methods provide better computational stability and are more considered at the early stage of modelling; the ALE method is more common in studies for specific injuries and should be used in conjunction with the previously mentioned methods.
Gan, Qiuyu, jiang, Yejie, Junpeng, Xu, Zhou, Runzhou, Zhang, Liying, Jiang, Binhui
Optimization of Console Armrest Design for Reduction of G-Values in Head Impact Testing2024-28-021212/5/2024
Head injuries from interior impacts during vehicle accidents are a significant cause of fatalities in India. Data from the National Crime Records Bureau (NCRB) for 2023 reveals that approximately 15% of the total 150,000 road fatalities were due to head impacts on vehicle interiors, resulting in about 22,500 deaths. Thus, head impact protection in a car crash is key during the design of vehicle interiors. IS 15223 and ECE-R21 provide specific guidelines for head impact testing of instrument panels and consoles in vehicles to ensure compliance with safety standards and minimize the risk of head injury during collisions. By systematically addressing each aspect of IS 15223 and ECE- R21 in the design, testing, and documentation phases, manufacturers can ensure that console armrests are optimized for safety. This approach not only helps meet regulatory standards but also enhances overall occupant protection in vehicles during collisions. The objective of this paper is to design a console armrest that meets stringent head impact testing requirements and thereby enhances occupant safety in automotive applications. The research focuses on optimizing the armrest’s structural integrity to withstand dynamic loads and to transfer or dissipate that impact energy effectively.
Malhotra, Deepak, Vaishnav, Suresh, Sureshkumar Presannakumari, Rajasilpi, Mangal, Gautam, Keshri, Amit
Toward a Test-Based Methodology to Evaluate Unrestrained Torso Neck Braces Using the Hybrid III ATD and MATD Neck09-12-03-001211/23/2024
The introduction of unrestrained torso neck braces as a safety intervention for helmeted motorcycle riders has introduced a set of unsolved challenges. Understanding the injury prevention afforded by these devices depends on a reliable test methodology by which to critically evaluate their efficacy against the most common mechanisms of neck injury. An inverted pendulum test is proposed to evaluate compression flexion (CF), tension flexion (TF), and tension extension (TE) of the neck using a Hybrid III anthropomorphic test device (HIII ATD) neck and a motorcycle-specific ATD (MATD) neck. In addition to investigating methods to quantify the beneficial effects of a neck brace, potential adverse effects of such a device are evaluated by measuring and evaluating relevant neck response measures. To that end, measured data using a current neck brace were analyzed and applied to various injury criteria related to the ATD neck used to compare the injury risk predicted by each parameter. The HIII ATD neck allows for a more conservative evaluation due to its exaggerated response in compression and may be more suitable in evaluating the neck injury criterion and injury risk in CF loading for low energy impacts. The MATD neck is limited to certain impact modalities, particularly the uncoupled behavior between head and neck during hyperextension, and individual neck measures at lower impact energy due to its limited structural integrity in direct head impacts. In the proposed tests, injury mechanisms were initially associated with a pre-impact head orientation and expected head and neck motion. However, these associations are not definitive. Although the most relevant neck injury mechanisms related to the unrestrained torso were addressed, the authors suggest that the presented tests are supplemented by a method to evaluate higher energy vertex impacts as a means to determine a neck brace’s efficacy during this loading modality.
de Jongh, Cornelis U., Basson, Anton H., Knox, Erick H., Leatt, Christopher J.
Finite Element Comparison of Human and Hybrid III Responses in the Airworthiness Certification of Normal Aircraft2024-01-701811/15/2024
With the capability of predicting detailed injury of occupants, the Human Body Model (HBM) was used to identify potential injuries for occupants in car impact events. However, there are few publications on using HBM in the aviation industry. This study aims to investigate and compare the head, neck, lumbar spine and thoracic responses of the Hybrid III and the THUMS (Total Human Model for Safety) model in the horizontal 26g and vertical 19g sled tests required by the General Aviation Aircraft Airworthiness Regulations. The HIC of THUMS and Hybrid III did not exceed the requirements of airworthiness regulations. Still, THUMS had higher intracranial pressures and intracranial stresses, which could result in brain injury to the occupants. In vertical impact, the highest stress of the neck of THUMS appears at the cervical spine C2 and the upper neck is easily injured; in horizontal impact, the cervical spine C7 has the highest load, and the lower neck is easily injured. Due to the low biofidelity of the Hybrid III ATD neck structure, the injuries that appeared at different neck locations cannot be identified by the Hybrid III ATD. Because of the submarining phenomenon, the lumbar spine load and bending moment of the THUMS are much smaller than that of the ATD model, which shows a lower risk of injuries. In both impact scenarios, the THUMS chest deformation was higher. In the vertical 19g impact, the THUMS developed much higher shoulder belt loads than the ATD. The results indicate the Hybrid III ATD underestimates the risk of injury to passengers' heads and chests, while overestimating the risk to the lumbar spine compared to THUMS. Furthermore, due to limitations in the locations of sensors, the Hybrid III ATD is unable to identify the severe injury at lower neck and upper lumbar.
Shi, Xiaopeng, Ding, Xianghe, Guo, Kai, Liu, Tianfu, Xie, Jiang
Intracranial Displacements due to Blunt Force Impact in a Postmortem Human Surrogate Brain09-12-02-001111/12/2024
Prevention and diagnosis of traumatic brain injuries (TBI) are reliant on understanding the biomechanical response of the brain to external stimuli. Finite element models (FEM) and artificial head surrogates are becoming a common method of investigating the dynamic response of the brain to injurious impact and inertial stimuli. The accuracy and validity of these models is reliant on postmortem human subject (PMHS) research to produce biofidelic brain tissue responses. Previous PMHS research has been performed to measure intracranial pressures, displacements, and strains when subjected to impact and inertial loading; however, there remains a need for additional PMHS datasets to improve our understanding of the brain’s dynamics. The purpose of this study is to measure the relative brain–skull displacement in a PMHS specimen when subjected to blunt force impacts. A high-speed X-ray (HSXR) imaging system and embedded radiopaque elastomeric markers were used to record PMHS impacts at varying impact velocities for two specimens: specimen CO-108 was subjected to a series of frontal impacts and specimen CO-109 was subjected to a series of rear impacts. Brain–skull relative deformation in each specimen indicates that brain deformation is dependent both on anatomical regions and of impact direction.
Demiannay, Jean-Jacques, Rovt, Jennifer, Brannen, MacKenzie, Xu, Sheng, Kang, Gia, Yip, Ashley, Azadi, Amir Hossein, Dehghan, Parisa, Goodwin, Shannon, Taylor, Reggie, Poon, Katherine, Brien, Susan, Hoshizaki, Blaine, Karton, Clara, Petel , Oren
Comparison of Head Impact Biomechanics across Multiple Sports09-12-02-001811/12/2024
Athletes may sustain numerous head impacts during sport, leading to potential neurological consequences. Wearable sensors enable real-world head impact data collection, offering insight into sport-specific brain injury mechanisms. Most instrumented mouthguard studies focus on a single sport, lacking a quantitative comparison of head impact biomechanics across sports. Additionally, direct comparison of prior studies can be challenging due to variabilities in methodology and data processing. Therefore, we gathered head impact data across multiple sports and processed all data using a uniform processing pipeline to enable direct comparisons of impact biomechanics. Our aim was to compare peak kinematics, impulse durations, and head impact directionality across ice hockey, American football, rugby, and soccer. We found that American football had the highest magnitude of head impact kinematics and observed directionality differences in linear and angular kinematics between sports. On the other hand, there were no significant differences in impulse durations, which was unexpected given the different impacting objects and protective equipment across sports. In future work, we aim to expand our dataset to better match sports for understanding the influence of sex, equipment, and playstyle on head impact biomechanics.
Masood, Zaryan Z., Luke, David S., Kenny, Rebecca A., Bondi, Daniel R., Clansey, Adam C., Wu, Lyndia C.
The Implications of Surface Friction on Snowsport Helmet Oblique Impact Kinematics09-12-02-001711/12/2024
Head injuries account for 15% of snowsport-related injuries, and the majority of head impacts occur against ice or snow, low-friction surfaces. Therefore, this study aimed to evaluate how surface friction affects snowsport helmets’ oblique impact kinematics. Ten helmet models were impacted using an oblique drop tower with a 45-degree anvil and NOCSAE headform, at three locations, two surface friction conditions, and a drop speed of 5.0 m/s. Our findings indicate that friction affects peak linear acceleration, peak rotational acceleration, and peak rotational velocity during helmet impacts, with changes in post-impact rotation and impact response varying by location. Surface friction affects head impact kinematics, underscoring the need for sport-specific lab testing and emphasizing the need for friction-specific and sport-specific testing, particularly for snowsports, where surface conditions like snow and ice can alter kinematics.
Stark, Nicole E.-P., Calis, Andrew, Wood, Matthew, Piwowarski, Summer Blue, Dingelstedt, Kristin, Begonia, Mark, Rowson, Steve
Quantifying and Comparing the Intersegmental Kinematics of the Pediatric Whole Cervical Spine to Individual Motion Segment Kinematics in a Six-Year-Old Postmortem Human Surrogate09-12-02-001011/12/2024
Mitigating both neck and head injuries in the pediatric population relies heavily on improving our understanding of the underlying biomechanics of the pediatric cervical spine. The tensile response for individual motion segments and the whole cervical spine (WCS) has been reported, but there is no data characterizing the intersegmental kinematics of pediatric WCS under axial loading conditions. The structural response of motion segments and WCS provide valuable data for the design and validation of biofidelic physical and computational models for the pediatric population. However, the use of motion segment data to construct WCS response or the use of WCS axial response to accurately characterize intersegmental response may present limitations to accurately modeling the pediatric cervical spine response. In this secondary analysis of the work of Luck et al. (2008, 2013), the fixed-fixed, low load, quasi-static tensile response of the WCS and individual motion segments (O-C2, C4-C5, and C6-C7) of a six-year-old postmortem human surrogate (PMHS) was investigated to quantify and compare the intersegmental kinematics under both conditions. In the whole spine, O-C2, C3-C4, C6-C7, and C7-T1 exhibited a tensile response, C2-C3 and C5-C6 exhibited a compressive response, and C4-C5 did not exhibit an appreciable response in the axial loading direction. Furthermore, when compared to the tensile behavior of the individual motion segment load-controlled tests, C6-C7 exhibited reduced axial displacement and an increased stiffness at higher loads (≥13.5 N), suggesting the recruitment of more superficial ligamentous layers that span multiple vertebrae in the whole spine. Regarding vertical displacement and rotation, O-C2 exhibited the largest amount of rotation of 5.57 degrees in flexion and all segments exhibited some amount of anterior–posterior (AP) displacement. The intersegmental kinematics provide biomechanical response data that may support both physical and computational surrogate design and validation as well as data for comparison to isolated FSU testing conditions.
Liu, Miranda, Luck, Jason F.
Seeing Is CommunicatingTBMG-514579/4/2024
Communicating when traumatic brain injury, stroke, or disease has made speech impossible can be daunting. But specialized eye-tracking technology uses eye movement to enable people living with disabilities to connect one-on-one, over the phone, or via the internet.
A Methodology to Evaluate Unrestrained Torso Neck Braces for Near Vertex Impacts09-12-03-00108/22/2024
The advent of neck braces for the helmeted motorcycle rider has introduced a pertinent research question: To what extent do they reduce measures related to the major mechanism of neck injury in unrestrained torso accidents, i.e., compression flexion (CF)? This question requires a suitable method of testing and evaluating the measures for a load case resulting in the required mechanism. This study proposes a weighted swinging anvil striking the helmeted head of a supine HIII ATD by means of a near vertex impact with a low degree of anterior head impact eccentricity to induce CF of the neck. The applied impact was chosen for the baseline (no neck brace) so that the upper and lower neck axial forces approached injury assessment reference values (IARV). The head impact point evaluated represents those typically associated with high-energy burst fractures occurring within the first 20 ms, with possible secondary disruption of posterior ligaments. The proposed test can be used to evaluate the initial and secondary period of neck loading resultant from a near vertex impact and the effect of a neck brace thereon. The presented case study shows that unless almost touching the helmet, neck braces are likely to have a negligible effect on the axial load response of the neck within the first 20 ms after impact and are, therefore, unlikely to affect injury risk related to initial compressive loading of the neck. Conversely, a neck brace can affect neck response in bending during a near vertex CF loading event. Hence, assessing these devices is important to determine their potential in stabilizing the spine. The proposed test shows that the neck loading mechanism does not necessarily correspond with the observed head motion, especially in the early stages of neck response. These head/neck kinetics are important to consider when designing an evaluation load case.
de Jongh, Cornelis U., Basson, Anton H., Knox, Erick H., Leatt, Christopher J.
Evaluation of DAMAGE Algorithm in Frontal Crashes2023-22-00064/17/2024
With the current trend of including the evaluation of the risk of brain injuries in vehicle crashes due to rotational kinematics of the head, two injury criteria have been introduced since 2013 – BrIC and DAMAGE. BrIC was developed by NHTSA in 2013 and was suggested for inclusion in the US NCAP for frontal and side crashes. DAMAGE has been developed by UVa under the sponsorship of JAMA and JARI and has been accepted tentatively by the EuroNCAP. Although BrIC in US crash testing is known and reported, DAMAGE in tests of the US fleet is relatively unknown. The current paper will report on DAMAGE in NCAP-like tests and potential future frontal crash tests involving substantial rotation about the three axes of occupant heads. Distribution of DAMAGE of three-point belted occupants without airbags will also be discussed. Prediction of brain injury risks from the tests have been compared to the risks in the real world. Although DAMAGE correlates well with MPS in the human brain model across several test scenarios, the predicted risk of AIS2+ brain injuries are too high compared to real-world experience. The prediction of AIS4+ brain injury risk in lower velocity crashes is good, but too high in NCAP-like and high speed angular frontal crashes.
Prasad, Priya, Barbat, Saeed D., Kalra, Anil, Dalmotas, Dainius J.
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