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A highly controlled six-vehicle crash test program was conducted to provide an estimate of the test-to-test variability of the NHTSA-proposed passenger car dynamic side impact test procedure. The results of this program showed that the rear seat test dummy response measurements are especially sensitive to various parameters of the test procedure. This paper provides estimates of front and rear seated SID dummy response measurement variability in four-door, 1990 Ford Taurus vehicles. Conclusions and recommendations from this controlled crash test program are made to provide guidance to help reduce the test-to-test variability of the test dummy responses.

This report describes an experimental validation of an ellipsoid-to-foam contact model. A series of static foam tests was conducted using Side Impact Dummy rib cage, pelvis, upper leg, and wooden ellipsoids as impactors to validate a theoretical foam contact model previously developed. Predicted results of contact forces, calculated using the uni-axial stress-strain relationship and contact areas, yield good correlation with the test data. These studies used CFC foams and were conducted prior to switching to water-blown foam material development. The ellipsoid-to-foam contact model is being integrated into a MADYMO side impact model. The MADYMO/foam simulation model can then be used to help evaluate design variable tradeoffs (e.g., door thickness vs. body side structures and foam padding requirement vs. interior package) thereby reducing the current dependency on testing, bolster development time, and cost.

This paper describes the development of a Dynamic Door Component Test Methodology (DDCTM) for side impact simulation. A feasibility study of the methodology was conducted using a MADYMO computer model by taking parameters such as door pre-crush, door-to-SID (Side Impact Dummy) contact velocity and the deceleration profile into consideration. The prove-out tests of this methodology was carried out on a dynamic sled test facility. The DDCTM has been validated for various carlines. In addition, various existing dynamic component test methods are reviewed. In our approach, a pre-crushed door, mounted on a sled, strikes a stationary SID at a pre-determined velocity. A programmable hydraulic decelerator is used to decelerate the sled to simulate the barrier/door deceleration pulse during door-to-SID contact period. This test procedure provides excellent correlation of the SID responses between the component test and the full-scale vehicle test.

Various foam models are developed using LS-DYNA3D and validated against experiments. Dynamic and static stress-strain relations are obtained experimentally for crushable and resilient foam materials and used as inputs to the finite element analyses. Comparisons of the results obtained from different foam models with test data show excellent correlations for all the cases studied.

Various foam models are developed using LS-DYNA3D and the model predictions were validated against experiments. Dynamic and static stress-strain relations are obtained experimentally for crushable and resilient foam materials and used as inputs to the finite element analyses. Numerous simulations were carried out for foams subjected to different loading conditions including static compression and indentation, and dynamic impacts with a rigid featureless and a rigid spherical headform. Comparisons of the results obtained from different foam models with test data show appropriate correlations for all the cases studied. Parametric studies of the effects of tensile properties of foam material and the interface parameters on foam performance are also presented.

This paper provides a methodology for adjustment of off-speed head impact test data to the required 24.14 km/h for interior head impact. The “Normalization Process” utilizes the Generic Waveform Concept for its basic foundation. Predicted results from FE Head Impact Simulation Model were used to validate the Normalization Process. It is recommended that Normalization should be applied to cases where impact velocities are within ±0.8 km/h speed difference. In general, Normalizing down-speed (from 24.94 to 24.14 km/h) is preferred over Normalizing up-speed (23.33 to 24.14 km/h). One must always check for potentially severe “bottom-out” condition by examining the pulse shape for any abrupt peaks in headform deceleration. The Normalization Process should not be applied to “glancing” impacts in which the impact and rebound vectors are not colinear.

This paper describes the development of an automated Door Test Facility for implementing the Door Component Test Methodology for side impact analysis. The automated targeting and loading of the door inner/trim panels with Side Impact Dummy (SID) ribcage, pelvis, and leg rams will greatly improve its test-to-test repeatability and expedite door/trim/armrest development/evaluation for verification with the dynamic side impact test of FMVSS 214 (Occupant Side Impact Protection). This test facility, which is capable of evaluating up to four (4) doors per day, provides a quick evaluation of door systems. The results generated from this test methodology provide accurate input data necessary for a MADYMO Side Impact Simulation Model. The test procedure and simulation results will be discussed.

Currently, the three (3) methods for calculating the HIC-value are: 1) direct computation method, 2) utilization of maximization requirement approach developed by Chou and Nyquist, and 3) a partitioning technique. A method which involves the adoption of an optimization approach for HIC calculation is discussed in this study. This optimization technique, which has previously been applied to Boundary Element Method (BEM), employs an improved constrained variable metric method in recursive quadratic programming. This technique was applied to three theoretical and ten experimental acceleration pulses; the results compare extremely well with exact solution and/or other numerical methods. It is concluded that this optimization scheme provides accurate HIC calculations. A study is planned to investigate the feasibility of extending the application of this optimization technique to an integrated trim/foam/sheet metal pillar system for improved interior head impact protection study.

The objective of this study was to determine dynamic tensile characteristics of various door trim materials and to recommend a practical test methodology. In this study, Polypropylene (PP) and Acrilonitryl Butadiene Styrene (ABS) door trim materials were tested. Slow speed (quasi-static-0.021 mm/s) and high speed tests were conducted on a closed loop servo-hydraulic MTS system. The maximum stress of these materials increased from quasi-static to dynamic test conditions (as much as 100%). The dynamic stiffness of PP increased two times from quasi-static tests. No significant change in stiffness was observed for ABS during quasi-static and dynamic tests at different strain-rates. Quasi-static and medium strain-rate (10-20 mm/mm/s) tests may be adequate in providing data for characterizing the dynamic behavior of trim materials for CAE applications. Strain gages can be used to measure the quasi-static and in some cases, dynamic strain.

This paper describes further developments of the MVMA-2D model including program modifications of the air bag and the energy absorbing steering assembly submodels. The air bag submodel and the steering assembly submodel in the MVMA-2D crash victim simulation are independently formulated. No coupling exists between these two submodels to permit simulation of the kinematics of an anthropomorphic dummy restrained by a driver air bag restraint system mounted on a collapsible steering column. The development effort of integrating both submodels to provide the MVMA-2D model with such a capability is presented. The integrated model has been successfully utilized in simulating dynamic responses, in frontal impact situations, of a dummy restrained by a driver air bag restraint system mounted on a collapsible steering column. Validations of the model were made by comparing simulation results with experimental test data.

NHTSA is expected to publish a final rule on Interior Head Impact (as an amendment to FMVSS 201) by early 1995. One of the Interior Head Impact Study objectives is to develop a methodology for estimating the minimum head impact space requirements to meet this regulation. The physical parameters affecting the HIC (Head Injury Criterion) are impact velocity, maximum headform stopping distance, peak deceleration, and pulse duration. The equations for estimating the HIC vs. Head Impact Space Requirements are formulated by relating these physical parameters to the Idealized Waveforms of Square Wave, Sine Wave, and Haversine Wave. This methodology has been extended to include the Generic Waveform. Tabulations of Maximum Headform Stopping Distance Requirement vs. Peak Deceleration, Pulse Duration, and HIC for the three Idealized Waveforms at 6.7 m/s (15 mph) impact speed have been generated to provide an estimate of the head impact package space requirement.

This paper describes the development of a new component test methodology concept for simulating NHTSA side impact, to evaluate the performance of door subsystems, trim panels and possible safety countermeasures (foam padding, side airbags, etc.). The concept was developed using MADYMO software and the model was validated with a DOT-SID dummy. Moreover, this method is not restricted to NHTSA side impact, but can be also be used for simulating the European procedure, with some modifications. This method uses a combination of HYGE and VIA decelerator to achieve the desired door velocity profile from onset of crash event until door-dummy separation, and also takes into account the various other factors such as the door/B pillar-dummy contact velocity, door compliance, shape of intruding side structure, seat-to-door interaction and initial door-dummy distance.