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Pal, Chinmoy
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Real World Accident Analysis of Driver Car-to-Car Intersection Near-Side Impacts: Focus on Impact Location, Impact Angle and Lateral Delta-V

NTCNA USA-John Combest
Nissan Motor Co., Ltd.-Chinmoy Pal, Shigeru Hirayama, Shinichi Hayashi
Published 2018-04-03 by SAE International in United States
In total, 865 intersection car-to-car crashes (NASS-CDS CY 2004-2014) are analyzed in detail to determine the injury level outcome based on different crash factors, such as delta-V, age, airbag deployment, number of events, impact locations (F,Y,P,Z,D,B-regions based on CDC codes), amount of compartment intrusion and impact angle. A multivariate logistic regression test was performed to predict the probability of MAIS3+ serious injuries using lateral delta-V, location of maximum deformation from B-PLR, age (0: <60/1: ≥60 years), number of events (0: single/ 1: multiple), intrusion (0: <16cm/ 1: ≥16cm), side airbag deployment (yes/no) and direction of impact (0: 9/ 1: 10 o’clock). It is found that direction of impact is one of the significant (p<0.05) parameters and 10 o’clock angle impact has more influence than 9 o’clock perpendicular lateral impact. Frequency of AIS3+ injuries was high in Y-region impact cases. A sensitivity analysis of serious injuries is performed with respect to lateral delta-V based on logistic regression equation. The probability of serious injury increases more than 2 times when the angle of impact changes from 9 to…
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Vehicle’s Front End Profile Influence on Pedestrian Sensing System Using In-House Developed PDI-2 and Child FE Models

Nissan Motor Ltd.-Chinmoy Pal, Tomosaburo Okabe, Munenori Shinada, Kazuto Sato
RNTBCI-Kulothungan Vimalathithan, Jeyabharath Manoharan, Pratapnaidu Vallabhaneni
Published 2016-04-05 by SAE International in United States
Many active safety systems are being developed with the intent of protecting pedestrians namely; pedestrian airbags, active hood, active emergency braking (AEB), etc. Effectiveness of such protection system relies on the efficiency of the sensing systems. The pop-uphood system was developed to help reduce pedestrian head injuries. A pop-up system is expected to make full deployment of the hood before the pedestrian’s head could hit the hood. The system should have the capability to detect most road users ranging from a six year old (6YO) child to a large male. To test the sensing system, an impactor model (PDI-2) was developed. Sensor response varies for vehicles with different front end profile dimensions. To study numerically the sensor response characteristics with respect to different front end parameters, (a) PDI-2 FE model was developed and validated, (b) FE model of sensor was developed and validated, (c) Sensor FE model was incorporated in the vehicle and it was simulated against the PDI-2 FE. The results were validated with physical experiments, (d) Vehicles with different front end profile models…
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Effect of Vehicle's Front End Profile on Pedestrian's Lower Extremity Injury Pattern in Real World and Verification by Large Male FE Human Model

Nissan-Chinmoy Pal, Tomosaburo Okabe, Munenori Shinada
RNTBCI-Kulothungan Vimalathithan, Jeyabharath Manoharan
Published 2015-04-14 by SAE International in United States
Logistic regression analysis for accident cases of NASS-PCDS (National Automotive Sampling System-Pedestrian Crash Data Study) clearly shows that the extent and the degree of pedestrian's lower extremity injury depend on various factors such as the impact speed, the ratio of the pedestrian height to that of the bonnet leading edge (BLE) of the striking vehicle, bumper to knee ratio, bumper lead angle, age of the pedestrian, and posture of the pedestrian at the time of impact. The pedestrian population is divided in 3 groups, equivalent to small-shorter, medium-height and large-taller pedestrian with respect to the “pedestrian to BLE height-ratio” in order to quantify the degree of influence of lower leg injuries in each group. Large adult male finite element model (95th percentile male: 190 cm and 103 kg) was developed by morphing the Japan Automobile Manufacturers Association (JAMA) 50th percentile male. Lower extremity of developed large male was fine meshed to predict the fractures accurately. A car model was systematically morphed to create different designs having various front end profile dimensions. Large male model with…
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Estimation of Pelvis Injuries and Head Impact Time using Different Pedestrian Human FE Models

Nissan-Chinmoy Pal, Tomosaburo Okabe
RNTBCI-Kulothungan Vimalathithan, Jeyabharath Manoharan, Muthukumar Muthanandam, Satheesh Narayanan
Published 2014-04-01 by SAE International in United States
A logistic regression analysis of accident cases in the NASS-PCDS (National Automotive Sampling System-Pedestrian Crash Data Study) database clearly shows that pedestrian pelvis injuries tend to be complex and depend on various factors such as the impact speed, the ratio of the pedestrian height to that of the bonnet leading edge (BLE) of the striking vehicle, and the gender and age of the pedestrian. Adult female models (50th %ile female AF50: 161 cm and 61 kg; 5th %ile female AF05: 154 cm and 50 kg) were developed by morphing the JAMA 50th %ile male AM50 and substituting the pelvis of the GHBMC AM50 model. The fine-meshed pelvis model thus obtained is capable of predicting pelvis fractures. Simulations conducted with these models indicate that the characteristics of pelvis injury patterns in male and female pedestrians are influenced by the hip/BLE height ratio and to some extent by the pelvis bone shape. A previously developed six-year-old (6YO) child pedestrian model and the newly developed models were used to estimate the head impact time (HIT) for a typical…
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Estimation of Body Mass Index Effect on Lower Extremity Injuries for Lateral Collision With-out Airbag

Nissan-Chinmoy Pal, Tomosaburo Okabe
RNTBCI-Kulothungan Vimalathithan, Muthukumar Muthanandam, Jeyabharath Manoharan, Satheesh Narayanan
Published 2014-04-01 by SAE International in United States
A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries. Occurrence of pelvis injury was found to be influenced by BMI and was validated with logistic regression analysis. Apart from BMI, gender…
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Flex-PLI Application to High-Bumper Vehicles - Optimization of Supplemental Weight

SAE International Journal of Transportation Safety

Nissan Motor Company, Ltd.-Yoshiko Kawabe, Chinmoy Pal, Hiroyuki Okuyama, Tomosaburo Okabe
  • Journal Article
  • 2013-01-0215
Published 2013-04-08 by SAE International in United States
The Flexible Pedestrian Legform Impactor (Flex-PLI) was developed to evaluate the risk of pedestrian lower extremity injuries. However, it has been pointed out that the post-crash kinematics of the Flex-PLI differs from those of a human body when it is hit by high-bumper vehicles. This paper describes the feasibility of applying the Flex-PLI to a wide range of vehicle types by adding a supplemental weight. The following aspects are discussed in this regard: A human body finite element (FE) model analysis shows that the upper body of the Flex-PLI is not involved in tibia and knee ligament injury indexes in the first contact with a high-bumper vehicle.A rigid bar model is introduced and its rotational energy ratio is formulated. The rotational energy ratio is employed to evaluate the post-crash kinematics of the Flex-PLI and a human leg model.The feasibility of adding a supplemental weight to the Flex-PLI with regard to the bumper height is discussed.
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Effect of Impact-Triggered Automatic Braking in Multiple Impact Crashes

Nissan Motor Company Ltd.-Atsushi Togawa, Daisuke Murakami, Chinmoy Pal, Tomosaburo Okabe
Published 2012-04-16 by SAE International in United States
This study proposes an impact-triggered automatic braking system as a potential safety improvement based on the characteristics of the Multiple Impact Crashes (MICs). The system activates with a signal of airbag deployment in a collision to reduce the vehicle speed in the subsequent collisions. The effectiveness was estimated by an in-depth review of the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). The cases were extracted on the basis of the 3-point lap and shoulder belted occupants, incurring Maximum Abbreviated Injury Scale level 3 to 6 injuries (MAIS 3+), in the crashes occurred from 2004 to 2006, without vehicle rollover or occupant ejection, where the involved vehicles were 2000 and newer model year cars and light trucks. They were classified into three categories: (a) Single Impact Crash (SIC), (b) Multiple Impact Crash in which the Severest Impact Event occurred at the 1st collision (MIC-SIE 1) and (c) Multiple Impact Crash in which the Severest Impact Event occurred at or after the 2nd Impact Event (MIC-SIE 2+). Among the MIC-SIE 2+, we focused on the cases where…
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Different Factors Influencing Post-crash Pedestrian Kinematics

SAE International Journal of Passenger Cars - Mechanical Systems

Nissan Motor Company Ltd.-Yoshiko Kawabe, Toshiyuki Asai, Daisuke Murakami, Chinmoy Pal, Tomosaburo Okabe
  • Journal Article
  • 2012-01-0271
Published 2012-04-16 by SAE International in United States
Pedestrian crashes are the most frequent cause of traffic-related fatalities worldwide. The high number of pedestrian accidents justifies more active research work on passive and active safety technology intended to mitigate pedestrian injuries. Post-impact pedestrian kinematics is complex and depends on various factors such as impact speed, height of the pedestrian, front-end profile of the striking vehicle and pedestrian posture, among others. The aim of this study is to investigate the main factors that determine post-crash pedestrian kinematics. The injury mechanism is also discussed.A detailed study of NASS-PCDS (National Automotive Sampling System - Pedestrian Crash Data Study, US, 1994-1998), showed that the vehicle-pedestrian interaction in frontal crashes can be categorized into four types: “Thrown forward”, “Wrapped position”, “Slid to windshield” and “Passed over vehicle”. A Principal Component Analysis (PCA) was performed and 11 independent factors were identified for study from a set of 26 variables, as defined in NASS-PCDS. Pedestrian-vehicle size ratio and the impact speed are the two most influential factors that determine post crash pedestrian kinematics. However, the standing posture of a taller…
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Development of a Long-Range Ultrasonic Sensor for Automotive Application

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Kyoto Institute of Technology-Akira Ohsumi
Nissan Motor Co., Ltd.-Takafumi Kamemura, Hideo Takagi, Chinmoy Pal
  • Journal Article
  • 2008-01-0910
Published 2008-04-14 by SAE International in United States
In recent years, short-range sensors like stereo cameras, radar and infrared cameras have become essential components of safety systems and user-friendly convenience systems, such as pre-crash safety or parking assist systems. However, they are generally too expensive to implement on lower-end vehicles. On the other hand, a conventional backup-assistance sonar has a very small coverage area, but it is more cost effective than the above-mentioned sensors.This paper proposes an effective method to increase the range of detection of conventional sensor with the help of a pseudo-Wigner distribution-based likelihood function. The reflected wave detected by maximizing the p-WD-based likelihood function with respect to the parameter related to the time delay. This method is verified in actual experiment and the maximum detection range was found to be extended by about 2.5 times beyond that of the conventional approach.
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Virtual Simulation Tool for Real-World Rollover Accidents by Combining PC-Crash and FEA

NISSAN MOTOR CO., LTD.-Tyuuji Ootani, Chinmoy Pal
  • Technical Paper
  • 2007-08-0658
Published 2007-10-01 by Society of Automotive Engineers of Japan in Japan
Rollover accidents have drawn greater attention, leading to more active research from different perspectives. This ranges from investigations for elucidating the basic causes and mechanisms of rollover accidents to studies of more advanced occupant protection measures. As the phenomenon of a rollover accident is longer in duration than frontal, side or rear impacts, it is relatively difficult to simulate such accidents for experimental verification and also for proper evaluation of occupant restraint system performance. In this work, we focused on the trip-over type, which occurs most frequently, and performed simulations to reproduce real-world accidents by combining PC-Crash and FEA. Soil trip-over simulation was carried out based on real-world accidents. Based on rigid body dynamics, PC-Crash software was chosen to make an accident reconstruction analysis of some selected cases chosen from an accident database (NASS-CDS). Through a process of iteration the overall kinematics of the vehicle movement before and after the crash was captured. The output of the PC-Crash simulation was then used as the initial input conditions (i.e., speed, deceleration, etc.) of a detailed finite…