Browse Topic: Anthropometrics
Pelvic orientation in vehicles is crucial for preventing injuries and creating safer vehicles and restraint systems. A better understanding of pelvic orientation could provide more accurate anthropomorphic test device (ATD) models of underrepresented populations such as obese individuals, children, and small females. Sonomicrometry is the use of piezoelectric transducers that transmit ultrasound signals to each other to measure the distance between them. These signals may be aggregated using triangulation. In this experiment, ultrasound crystals were secured to the surface of a porcine surrogate to evaluate pelvic movement. This data was then processed using Sonometrics software to generate a 3D model of four static positions and three dynamic tests. The test was validated using a camera and a 3D measurement arm (CMM) to validate XYZ positions. This article discusses how this method could be helpful for developing more accurate ATD models, preventing fatalities in vehicle crashes.
Thorax injuries are a significant cause of mortality in automotive crashes, with varying susceptibility across sex and age demographics. Finite element (FE) human body models (HBMs) offer the potential for injury outcome analysis by incorporating anthropometric variations. Recent advancements in material constitutive models, cortical bone fracture and continuum damage mechanics model (CFraC) and an orthotropic trabecular bone model (OrthoT), offer the opportunity to further improve rib models. In this study, the CFraC and OrthoT material modes, coupled with age-specific material properties, were progressively implemented to the Global Human Body Model Consortium small female 6th rib. Four distinct 6th rib models were developed and compared against sex and age-specific experimental data. The updated material models notably refined the predictions of force–displacement responses, aligning them more closely with the experimental averages. The CFraC model significantly improved the prediction of displacement at fracture, suggesting that incorporating stress triaxiality criteria can better account for the complex loading conditions ribs face in crashes, such as combined cortical tension and shear due to rib bending and torque. The study highlights the importance of using biofidelic material models and sex and age-specific data to simulate hard tissue fractures. The improved rib model demonstrates the effectiveness of integrating updated material properties and constitutive models to enhance injury prediction accuracy, which can inform better automotive safety designs and reduce mortality rates. Further research is recommended to extend these models across different demographic groups to fully capture population variability in rib fracture risk.
Occupant packaging is one of the key tasks involved in the early architectural phase of a vehicle. Accommodation, as a convention, is generally considered related to a car’s interior. Typical roominess metrics of the occupant like hip room, shoulder room, and elbow room are defined with the door in its closed condition. Several other roominess metrics like knee room, leg room, head room, and the like are also specified. While all the guidelines are defined with doors in their closed condition, it is also important to consider the dynamics that exist while the occupant is entering the vehicle. This article expands the traditional understanding of occupant accommodation beyond conventionally considering the vehicle interior’s ability to accommodate anthropometry. It broadens the scope to include dynamic conditions, such as when doors are opened, providing a more realistic and practical perspective. As a luxury car manufacturer, it is important to ensure the best overall customer experience at each touch point of the vehicle. When the customer enters the vehicle, there should be sufficient space provided by the door opening angle for a comfortable entry. The larger the opening angle, the better is the “entry accommodation” and vice versa. However, a wide-open door also necessitates the customer to bend more, after being seated, to reach its handle and close it. Thus, it becomes a compromise between what is possible as accommodation while the customer is entering the vehicle and how easy it is to close the door after being seated. The same logic holds good while the customer opens the door and exits the vehicle. This article aims to develop a customer loss function (CLF) between the two conflicting criteria by considering relevant anthropometric distribution of customers. This study focuses on driver compartment and the methodology developed is also pertinent to rear compartment with minor adaptations. Since driver’s seating position is heavily dependent on anthropometry, finer details of occupant seating position are also considered in this study. CLF developed in this article will help the designer and packaging engineers in making informed decisions on the door opening angle, by being conscious of the customer loss/gain for defined performance metrics.
In the context of Rotorcraft Pilot Couplings, the biomechanics of the pilot body play a fundamental role in determining the stability of the pilot-vehicle closed loop system. The response of the pilot body is, in turn, inherently stochastic, being a function of pilot biometrics and muscular activation. Coupling the statistical distribution of pilot biomechanical behavior determined in specialized experimental campaign with linear models of the helicopter heave dynamics, an uncertainty propagation procedure is developed, with the aim of estimating the statistical distribution of the stability margins of the closed loop pilot-vehicle system. Results obtained varying the collective lever characteristics, as well as the helicopter model parameters, align well with results obtained previously in deterministic settings. However, the new scheme allows to define quantitative robustness indices.
Game-like navigation visuals Conversational-style voice commands. Contactless biometric sensing. A tidal wave of software code and sensing technologies are being prepped to alter in-vehicle activities. Two supplier companies, TomTom and Mitsubishi Electric Automotive America (MEAA), recently presented their concept cockpit demonstrators to media at TomTom's North American corporate offices in Farmington Hills, Michigan. A few highlights:
Letter from the Special Issue Editors
Pyrotechnic seat belt pretensioners typically remove 8–15 cm of belt slack and help couple an occupant to the seat. Our study investigated pretensioner deployment on forward-leaning, live volunteers. The forward-leaning position was chosen because research indicates that passengers frequently depart from a standard sitting position. Characteristics of the 3D kinematics of forward-leaning volunteers following pretensioner deployment determines if body size is correlated with subject response. Nine adult subjects (three female), ages 18–43 years old, across a wide range of body sizes (50–120 kg) were tested. The age was limited to young, active adults as pyrotechnic pretensioners can deliver a notable force to the trunk. Subjects assumed a forward-leaning position, with 26 cm between C7 and the headrest, in a laboratory setting that replicated the passenger seat of a vehicle. At an unexpected time, the pretensioner was deployed. 3D kinematics were measured through a nine-camera motion capture system with reflective markers on the left and right glabella, tragus, manubrium, C7, lateral proximal head of humerus, olecranon process, patella, and lateral malleolus. For uniformity, all pretensioners were of the same model made by Autoliv and were dual systems (having deployment in the retractor and outbound anchor). The initial velocity of the trunk (first 50 ms) was dependent on the body size, with smaller subjects getting pulled back quicker. Following the first ~160 ms, there was a slight rebound where subjects briefly moved forward, followed by a period of high intersubject variance in movement. By isolating the effects of pyrotechnic pretensioner deployment on live volunteers, this study fills in an important gap in automotive safety research and may help with evaluating computer models or designing future restraint systems with advanced sensor technology where pretensioners deploy prior to significant vehicle deceleration.
In this study, a parametric thoracic spine (T-spine) model was developed to account for morphological variations among the adult population. A total of 84 CT scans were collected, and the subjects were evenly distributed among age groups and both sexes. CT segmentation, landmarking, and mesh morphing were performed to map a template mesh onto the T-spine vertebrae for each sampled subject. Generalized procrustes analysis (GPA), principal component analysis (PCA), and linear regression analysis were then performed to investigate the morphological variations and develop prediction models. A total of 13 statistical models, including 12 T-spine vertebrae and a spinal curvature model, were combined to predict a full T-spine 3D geometry with any combination of age, sex, stature, and body mass index (BMI). A leave-one-out root mean square error (RMSE) analysis was conducted for each node of the mesh predicted by the statistical model for every T-spine vertebra. Most of the RMSEs were less than 2 mm across the 12 vertebral levels, indicating good accuracy. The presented parametric T-spine model can serve as a geometry basis for parametric human modeling or future crash test dummy designs to better assess T-spine injuries accounting for human diversity.
During the early phase of vehicle development, one of the key design attributes to consider is the inner comfort for occupants. Internal spaciousness is the pillar that is responsible for user’s comfort and make into customer comfort needs in engineer metrics. Therefore, it is one of the key requirements to be considered during the vehicle design. Certain internal vehicle characteristics such as the size of shoulder room and the knee clearance are engineer metrics that influence the occupants’ perception for comfort. One specific characteristic influencing satisfaction is the headroom, which is the subject of this paper. The objective of this project is to analyze the relationship between the second row’s vehicle headroom with the occupant’s satisfaction under real world driving conditions, based on research, statistical data analysis and dynamic clinics.
We recently developed a three-direction (vertical, longitudinal, and lateral) coupled biodynamic model of seated posture under vibration. However, in that study we only tested one algorithm to identify the model parameters. This article investigates four different optimization solvers in Matlab®, i.e., particle swarm optimization (particleswarm), particle swarm and local optimization method (fmincon), genetic algorithm (ga) and local optimization method (fmincon), and local optimization method (fmincon) to identify coupled biodynamic model parameters. Based on the obtained parameters, it further compares experimental and simulation results to determine the best optimization solver in terms of the root mean square error (RMSE), linear regression (R 2), goodness of fit (ε), and Central Processing Unit (CPU) time. The results show that particle swarm optimization is the best one for identifying the biodynamic model’s parameters.
As the technology is growing and the development of electric vehicles is advancing, though there are advancements in technology, an automobile will always have the challenges of Noise, Vibration, and Harshness (NVH). With several years of study and research, various methodologies have been developed for the refinement of NVH in conventional vehicles (IC engines). But in terms of Battery Electric vehicles (BEV), we have new areas to explore to refine NVH. Currently, in the competitive market, developing a fully ground-up Electric vehicle (EV) is a challenge due to the aggressive product development timelines and high cost of development. As a result, many OEMs are considering converting their conventional existing vehicle to battery electric vehicles as they will need lesser product development timelines with their go-to-market strategy. This paper is focused on virtual NVH validations while converting an existing conventional vehicle body architecture to make it to a pure battery-operated electric vehicle architecture. This is accomplished by replacing the conventional powertrain systems and associated ancillary components with new power & energy systems on BEV. Architecture changes of the vehicle body need to be evaluated at various stages of vehicle development like BIW, trimbody & full vehicle as there may be a significant change in vibration transfers & noise transfers because of body mass and stiffness changes. A comparison is made between the conventional body architecture to the converted EV architecture for the change in the results. The structure-borne contributions from road input in BEV at full vehicle level are dominant, tactile & acoustic responses at driver location are evaluated & discussed in this paper.
ABSTRACT
Anthropometric data are crucial to vehicle ergonomics and safety design. The Chinese population has smaller body size than that of the Western population, while the current crash dummies were developed based on statures of the Western population. To provide effective crash protection for Chinese occupants and pedestrians, Chinese anthropometric data are needed. In the present study, three available Chinese anthropometric databases were surveyed and compared, and it was found that none of them can give reliable and complete anthropometric data. Thus, a mapping method was developed based on correlation and regression analysis to rebuild a reasonable and completed Chinese anthropometric database. Furthermore, the differences between Chinese body size and that of the current dummies were discussed and an example was given to demonstrate the influences of body size on injuries.
The various factors that affect ride comfort, including noise, vibrations and harshness (NVH) have been in focus in many research studies due to an increasing demand in ride comfort in the automotive industry. Vibrations have been highlighted as an important contribution to assess and predict overall ride comfort. The purpose of this paper is to present an approach to explain ride comfort with respect to vibration for the seated occupant based on a systematic literature review of previous fundamental research and to relate these results to the application in the contemporary automotive industry. The results from the literature study show that numerous research studies have determined how vibration frequency, magnitude, direction, duration affect human response to vibration. Also, the studies have highlighted how body posture, age, gender and anthropometry affect the human perception of comfort. An analysis was made of the consistency and inconsistency of the results obtained in the different studies. The deviations of the research results from real-world ride comfort in automotive vehicles were analyzed and divided into three groups: appreciable and consistent with industry results, appreciable and inconsistent with industry results and not appreciable in industrial results. The overall conclusion from this literature study was that there is much information available from laboratory studies regarding human response to vibrations, but there is a lack of studies that take into account all the different parameters that affect the overall ride comfort experience for automotive vehicle occupants.
In the fields of forensic accident reconstruction and biomechanical engineering, it is often necessary to estimate the length of a specific body segment for an individual, about whom little is known besides overall stature. Since body proportions and body segment lengths vary throughout the population, there will be some error in these estimations. The current study provides estimates for the accuracy of human body segment length predictions based on stature. In this study, four different methods for predicting body segment lengths based on stature were evaluated. Using publicly available adult and child anthropometric datasets, a leave-one-out cross validation analysis was conducted to evaluate the accuracy of each of the four methods in predicting body segment lengths. The results of the leave-one-out analysis showed that different prediction methods produced the best estimates for different body segment length measurements. When using the best method for each body segment, body segment lengths for an individual on average can be predicted within 2.5% of the actual measurement. The 50th percentile best estimates for each body segment length studied are provided for males and females, over a range of child and adult statures. The data presented in this study can be used to provide estimates of error rates of human body segment length predictions.
ABSTRACT The study describes the development of a plug-in module of the realistic 3D Digital Human Modeling (DHM) tool RAMSIS that is used to optimize product development of military vehicle systems. The use of DHM in product development has been established for years. DHM for the development of military vehicles requires not only the representation of the vehicle occupants, but also the representation of equipment and simulation of the impact of such equipment on the Warfighter. To simulate occupants in military vehicles, whether land or air based, realistically, equipment must become an integral part of the extended human model. Simply attaching CAD-geometry to one manikin’s element is not sufficient. Equipment size needs to be scalable with respect to anthropometry, impact on joint mobility needs to be considered with respect to anatomy. Those aspects must be integrated in posture prediction algorithms to generate objective, reliable and reproducible results to help design engineers making better products. Products that are safe, comfortable and appropriate for the Warfighter.
Vehicle Ergonomics can be simply defined as the ease and comfort with which the driver and occupants inside the passenger cell can access and use the vehicle controls or features. Ergonomics takes into consideration the ease of operating the vehicle and the comfort levels offered in terms of positioning of the controls and seating comfort as well. The research aimed to find statistically whether the controls and features inside the passenger compartment are within the anthropometric hand reach distance. The research was done by standardizing the driving position using SAE H-point standard document J4004 to fabricate an H-point tool to place each of the test cars seat according to standard dimensions. Therefore, the distances from both shoulder points of driver were taken into consideration. Moreover, the anthropometric data for 95th percentile human hand reach was used to test whether vehicle control parameters and features inside the passenger cell fall within the normal hand reach or not. The statistical data for 15 vehicles on sale in Indian market was then analyzed based on vehicle classes like Hatchback, Sedan, SUV and Luxury cars. The major controls like steering wheel, gear lever and parking brake were inside normal ergonomic reach but controls of features like trip meter, AC controls, multimedia and volume controls were found to be in most cases outside the hand reach. Need arises for research and development to ergonomically place these controls to prevent discomfort and distractions while driving which can lead to driver concentration off the road.
Digital human models (DHM) have greatly enhanced design for the automotive environment. The major advantage of the DHMs today is their ability to quickly test a broad range of the population within specific design parameters. The need to create expensive prototypes and run time consuming clinics can be significantly reduced. However, while the anthropometric databases within these models are comprehensive, the ability to position the manikin’s posture is limited and needs lot of optimization. This study enhances the occupant postures and their seating positions, in all instances the occupant was instructed to adjust to the vehicle parameters so they were in their most comfortable position. While all the Occupants are accommodated to their respective positions which finally can be stacked up for space assessments. This paper aims at simulating those scenarios for different percentiles / population which will further aid in decision making for critical parameters. Understanding the usage patterns of the seats by users will have huge impact on setting the target for overall vehicle length, including the luggage compartment. Although SAE J1517 [1] and SAE J4004 [2] recommends the practice of predicting the driver-selected seat position for population percentiles, but it is based on the US population. Premananth et al [3] suggests that a correction factor is required over prediction model of SAE J4004 and SAE J1517 to encompass the diversity found in India. Therefore, it becomes vital to examine the same scenarios either by user trials/clinics or by digital simulation for Indian population.
Items per page:
50
1 – 50 of 204