Occupant In Frontal Impact Research Articles

The Influence of Neck Muscle Activation on Head and Neck Injuries of Occupants in Frontal Impacts.

The aim of the present paper was to study the influence of neck muscle activation on head and neck injuries of vehicle occupants in frontal impacts. A mixed dummy-human finite element model was developed to simulate a frontal impact. The head-neck part of a Hybrid III dummy model was replaced by a well-validated head-neck FE model with passive and active muscle characteristics. The mixed dummy-human FE model was validated by 15 G frontal volunteer tests conducted in the Naval Biodynamics Laboratory. The effects of neck muscle activation on the head dynamic responses and neck injuries of occupants in three frontal impact intensities, low speed (10 km/h), medium speed (30 km/h), and high speed (50 km/h), were studied. The results showed that the mixed dummy-human FE model has good biofidelity. The activation of neck muscles can not only lower the head resultant acceleration under different impact intensities and the head angular acceleration in medium- and high-speed impacts, thereby reducing the risks of head injury, but also protect the neck from injury in low-speed impacts.

Effect of Automotive Side Member Materials on the Head Injury Criteria (HIC) and Chest Severity Index (CSI) of Adult Passenger

This paper presents the results for Head Injury Criteria (HIC) and Chest Severity Index (CSI) of an adult occupant in frontal impact. The component being studied is side member as impact energy absorber. Steel side member is used as the benchmark material, whereas aluminum alloy is used as lightweight material. Crash analyses are conducted using nonlinear finite element analysis software Ls-dyna. The effect of different types of aluminum alloy and component thickness on the HIC, CSI, weight and energy absorbed is assessed and discussed. A cost function is then formulated with the geometrical average method to solve the multi-objective problem. The HIC36 and CSI are set as minimum requirements in the optimization. The materials used was Aluminium alloy of AA 5182 AA5751. It was found that AA5751 with inner and outer thickness of 2.8 mm and 4.9 mm respectively, provides a reduction in mass of 1.03 kg compared with steel and has energy absorbed of 11.9 kJ. The lowest values of HIC36 and CSI obtained are 1146 and 665.4 respectively.

Effect of Automotive Side Member Materials on the Head Injury Criteria (HIC) and Chest Severity Index (CSI) of Adult Passenger

This paper presents the results for Head Injury Criteria (HIC) and Chest Severity Index (CSI) of an adult occupant in frontal impact. The component being studied is side member as impact energy absorber. Steel side member is used as the benchmark material, whereas aluminum alloy is used as lightweight material. Crash analyses are conducted using nonlinear finite element analysis software Ls-dyna. The effect of different types of aluminum alloy and component thickness on the HIC, CSI, weight and energy absorbed is assessed and discussed. A cost function is then formulated with the geometrical average method to solve the multi-objective problem. The HIC36 and CSI are set as minimum requirements in the optimization. The materials used was Aluminium alloy of AA 5182 AA5751. It was found that AA5751 with inner and outer thickness of 2.8 mm and 4.9 mm respectively, provides a reduction in mass of 1.03 kg compared with steel and has energy absorbed of 11.9 kJ. The lowest values of HIC36 and CSI obtained are 1146 and 665.4 respectively.

A Methodology to Estimate the Kinematics of Pediatric Occupants in Frontal Impacts

Objective: The goal of this article is to propose a new methodology to estimate the sagittal plane displacement of the head, spine, and pelvis of a 6-year-old (6YO) occupant during a high-speed frontal impact. Research has shown major discrepancies between the spinal kinematics of current pediatric anthropomorphic test devices and humans during frontal impacts. This article provides an estimation of the kinematics of a pediatric subject that may assist in the development of physical and computational models of a 6YO occupant in high-speed frontal impacts. Methods: This article presents data on 4 different experimental data sets corresponding to noninjurious low-speed (nominally 9 km/h) frontal impacts involving pediatric and adult volunteers and to low-speed (9 km/h) and high-speed (40 km/h) frontal impacts with postmortem human subjects (PMHS). Kinematic data from each subject were first normalized to the size of a 50th percentile within its age group. Two already published and commonly used scaling methods (mass scaling and the Society of Automotive Engineers [SAE] scaling methods) were assessed using volunteer data. A new scaling method based on energy considerations was developed. Results: Both the mass scaling and the SAE scaling methods failed to predict the actual pediatric displacement at 9 km/h. The newly proposed method substantially improved the prediction of the pediatric kinematics at low speed and it was applied to the high-speed PMHS data to provide an approximation of the displacements of the head, thoracic spine, and pelvis of a 6YO occupant in a 40 km/h frontal impact. Conclusions: A new scaling method based on energy conservation improved the prediction of the displacement of the pediatric head, thoracic spine, and pelvis at 9 km/h. This method was then applied to the response of the PMHS in a high-speed impact to provide an approximation of the 6YO kinematics in a 40 km/h frontal impact. The article also discusses the limitations of the method, which failed to completely describe the kinematics of pediatric occupants.

Optimal Occupant Kinematics and Crash Pulse for Automobile Frontal Impact

Based on a lumped-parameter model of the occupant-vehicle system, optimal kinematics of the occupant in frontal impact are investigated. It is found that for the minimization of the peak occupant deceleration, the optimal kinematics move the occupant at a constant deceleration. Based on this the optimal vehicle crash pulse is investigated. The optimal crash pulse for passive restraint systems is found to be: a positive impulse at the onset, an immediate plunge followed by a gradual rebound, and finally a positive level period. The relation of the peak occupant deceleration to the impact speed, crash deformation, and vehicle interior rattlespace is established. The optimal crash pulse for active and pre-acting restraint systems is discussed.

Optimal Occupant Kinematics and Crash Pulse for Automobile Frontal Impact

Based on a lumped-parameter model of the occupant-vehicle system, optimal kinematics of the occupant in frontal impact are investigated. It is found that for the minimization of the peak occupant deceleration, the optimal kinematics move the occupant at a constant deceleration. Based on this the optimal vehicle crash pulse is investigated. The optimal crash pulse for passive restraint systems is found to be: a positive impulse at the onset, an immediate plunge followed by a gradual rebound, and finally a positive level period. The relation of the peak occupant deceleration to the impact speed, crash deformation, and vehicle interior rattlespace is established. The optimal crash pulse for active and pre-acting restraint systems is discussed.