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This paper presents the analytical results of two different computer simulations of the vehicle pedestrian impact; PROMETHEUS 2 and the MacLaughlin/Daniel (MACDAN) models. The results presented illustrate the simularity and differences between the two models and accuracy of both to predict the actual occurrance. Also presented is a discussion relative to the modeling techniques of obtaining data for the pedestrian. This presentation illustrates the scaling techniques and actual data obtained in order to accurately simulate the pedestrian.

This study involves two areas of research. The first is the finalization of the Pedestrian Crash Data Study (PCDS) in order to provide detailed information regarding the vehicle/pedestrian accident environment and how it has changed from the interim PCDS information. The pedestrian kinematics, injury contact sources, and injuries were analyzed relative to vehicle geometry. The second area presented is full-scale attempts at reconstruction of two selected PCDS cases using the Polar II pedestrian dummy to determine if the pre-crash motion of the pedestrian and vehicle could somehow be linked to the injuries and vehicle damage documented in the case.

This paper presents an interactive computer simulation of the pedestrian/vehicle interface. The simulation presents the results in an easy to analyze format including animation of the whole event. User requests for specific output data is available via a graphic menu. The model employs the use of the MacLaughlin/Daniel Computer Simulation developed by the National Highway Traffic Safety Administration. To illustrate the usefulness of the graphical and pictorial output, the results of a pedestrian/vehicle impact are presented.

This paper presents a methodology for validating vehicle stability and control computer simulations. Validation is defined as showing that, within some specified operating range of the vehicle, a simulation's predictions of a vehicle's responses agree with the actual measured vehicle's responses to within some specified level of accuracy. The method uses repeated experimental runs at each test condition to generate sufficient data for statistical analyses. The acquisition and reduction of experimental data, and the processing path for simulation data, are described. The usefulness of time domain validation for steady state and slowly varying transients is discussed. The importance of frequency domain validation for thoroughly validating a simulation is shown. Both qualitative and quantitative methods for the comparison of the simulation predictions with the actual test measurements are developed.

This research was to model a 6×4 tractor-trailer rig using TruckSim and simulate severe braking maneuvers with hardware in the loop and software in the loop simulations. For the hardware in the loop simulation (HIL), the tractor model was integrated with a 4s4m anti-lock braking system (ABS) and straight line braking tests were conducted. In developing the model, over 100 vehicle parameters were acquired from a real production tractor and entered into TruckSim. For the HIL simulation, the hardware consisted of a 4s4m ABS braking system with six brake chambers, four modulators, a treadle and an electronic control unit (ECU). A dSPACE simulator was used as the “interface” between the TruckSim computer model and the hardware.

This study investigated the jackknife stability of Class VIII double tractor-trailer combination vehicles that had mixed braking configurations between the tractor and trailers and dolly (e.g. ECBS disc brakes on the tractor and pneumatic drum brakes on the trailers and dolly). Brake-in-turn maneuvers were performed with varying vehicle loads and surface conditions. Conditions with ABS ON for the entire vehicle (and select-high control algorithm on the trailers and dolly) found that instabilities (i.e. lane excursions and/or jackknifes) were exhibited under conditions when the surface friction coefficient was 0.3. It was demonstrated that these instabilities could be avoided while utilizing a select-low control algorithm on the trailers and dolly. Simulation results with the ABS OFF for the tractor showed that a tractor equipped with disc brakes had greater jackknife stability.

During Phase VI of the National Highway Traffic Safety Administration's (NHTSA) Light Vehicle Rollover Research Program, three of the twenty-six light vehicles tested exhibited significant response asymmetries with respect to left versus right steer maneuvers. This paper investigates possible vehicle asymmetric characteristics and unintended inputs that may cause vehicle asymmetric response. An analysis of the field test data, results from suspension and steering parameter measurements, and a summary of a computer simulation study are also given.

This research focuses on the development and performance of analytical models to simulate a tractor-semitrailer in straight-ahead braking. The simulations were modified and tuned to simulate full-treadle braking with all brakes functioning correctly, as well as the behavior of the tractor-semitrailer rig under full braking with selected brakes disabled. The models were constructed in TruckSim and based on a tractor-semitrailer used in dry braking performance testing. The full-scale vehicle braking research was designed to define limits for engineering estimates on stopping distance when Class 8 air-braked vehicles experience partial degradation of the foundation brake system. In the full scale testing, stops were conducted from 30 mph and 60 mph, with the combination loaded to 80,000 lbs (gross combined weight or GCW), half payload, and with the tractor-semitrailer unladen (lightly loaded vehicle weight, or LLVW).

An existing tire model was investigated for additional normal load-dependent characteristics to improve the large truck simulations developed by the National Highway Traffic Safety Administration (NHTSA) for the National Advanced Driving Simulator (NADS). Of the existing tire model coefficients, plysteer, lateral friction decay, aligning torque stiffness and normalized longitudinal stiffness were investigated. The findings of the investigation led to improvements in the tire model. The improved model was then applied to TruckSim to compare with the TruckSim table lookup tire model and test data. Additionally, speed-dependent properties for the NADS tire model were investigated (using data from a light truck tire).

Composite material roof structures for multipurpose vehicles are comprised of a composite shell molded without metal frames as in most automobile rooftops. This paper experimentally analyzes the roof structure performance for a static uniformly distributed load over the roof surface and examines the tensile properties, effects of high temperatures and sound absorption characteristics of the random, chopped glass fiber reinforced epoxy resin material. The roof performance includes the load-strain history and the load-deflection behavior of the structure.

This paper presents an overview of the evolution of computer simulations in vehicle collision and occupant kinematic reconstructions. The basic principles behind these simulations, the origin of these programs and the evolution of these programs from a basic analytical mathematical model to a sophisticated computer program are discussed. In addition, a brief computer development history is discussed to demonstrate how the evolution of computer assisted vehicle accident reconstruction becomes feasible for a reconstructionist. Possible future research in computer reconstruction is also discussed.

Accident reconstruction encompasses the evaluation of a crash situation from evidence and observations available after the accident. Such evidence includes vehicular damage, property damage, marks, and witness statements. The reconstructionist is responsible for transforming this information into a theory of the accident sequence. In addition to satisfying the evidence and statements, the theory must also agree with the laws of physics which dictate reactions to forces and torques. The computer program presented here assists in this analysis by providing a graphical depiction of the accident scenario. This program is called ANMATE and utilizes simulation results prepared by the CRASH or SMAC program for vehicle motions. A number of features assist in viewing the accident from different points of view, allow the user to stop action, and provide other data presentation formats. A real world example is given.

Objectives. Examination of head injuries in the Pedestrian Crash Data Study (PCDS) indicates that many pedestrian head injuries are induced by a combination of head translation and rotation. The Simulated Injury Monitor (SIMon) is a computer algorithm that calculates both translational and rotational motion parameters relatable head injury. The objective of this study is to examine how effectively HIC and three SIMon correlates predict the presence of either their associated head injury or any serious head injury in pedestrian collisions. Methods. Ten reconstructions of actual pedestrian crashes documented by the PCDS were conducted using a combination of MADYMO simulations and experimental headform impacts. Linear accelerations of the head corresponding to a nine-accelerometer array were calculated within the MADYMO model's head simulation.

Two computer models, ABAG 19 and HSRI-3D, were validated against experimental data to determine and compare their capability for simulating the responses of air bag restrained automobile occupants in severe frontal collisions. Standard sets of model input parameters were developed for both driver and passenger. The primary objective was to determine which model was best suited for determining potential crashworthiness in a large number of production vehicles. Advantages and disadvantages of the models were determined, using criteria such as accuracy, ease of use, quality of documentation and user orientation.

A Computer Accident Simulation (CAS) is the application of dynamics to known physical evidence to yield a best approximation of the interactions of vehicles and other objects during the real world accident scenario. The simulation is based upon the reconstruction after an engineer's examination of the vehicles involved, the roadway (i.e., skid marks and gouges), and any substantiated evidence from witnesses. Examples of various cases are presented to illustrate the engineer's accident reconstruction and how the reconstruction is used to establish the computer simulation. The cases are used to explain the accuracy, features, advantages, and disadvantages of developing a computer accident simulation. During the interaction of the engineer and the graphics specialist, extra information such as witness viewpoint needs to be attained to make the computer simulation.

The objective of this paper is to investigate the effect of padding on the human thorax. Different types of padding are used in the computer simulations. Lumped models are developed to perform the simulations. Through the responses of the simulations one can determine what kind of padding is desired. This paper provides the first phase of using a computer-aided tool. Though much attention has been paid to either the investigation of padding or human thorax modelling, how the physical properties of padding affect thoracic protection is not well known. The combination of padding and the thorax needs a lot of effort to unveil their relationship. This paper attempts to provide the guideline of what a good padding material should be. The determination of an optimal padding is one of the goals in this study. Hopefully, the results of this paper can make a contribution to the vehicle safety design, especially the car door.

Seat belt usage in the United States is increasing dramatically, due in part to legislative action. In addition, education programs have improved public awareness of the need for automotive restraints in achieving crash survival and injury reduction. The safety consciousness level of automobile passengers is particularly strong among pregnant women. It is reasonable to expect wider use of seat belts by expectant mothers due to this acute attention to safety. The literature demonstrates that incorrect usage of seat belts is a cause of injury. This can be especially applicable during pregnancy when changes in anatomy dictate a change in belt positioning, Review of the literature shows that the technical issues associated with the use of current production belt restraint systems by pregnant women has not been addressed.

This paper discusses the derivation and validation of planar models of articulated vehicles that were developed to analyze jackknife stability on low-μ surfaces. The equations of motion are rigorously derived using Lagrange's method, then linearized for use in state-space models. The models are verified using TruckSim™, a popular nonlinear solid body vehicle dynamics modeling package. The TruckSim™ models were previously verified using extensive on-vehicle experimental data [1, 2]. A three-axle articulated model is expanded to contain five axles to avoid lumping the parameters for the drive and semitrailer tandems. Compromises inherent in using the linearized models are discussed and evaluated. Finally, a nonlinear tire cornering force model is coupled with the 5-axle model, and its ability to simulate a jackknife event is demonstrated. The model is shown to be valid over a wide range of inputs, up to and including loss of control, on low-and-medium-μ surfaces.

The Suspension Parameter Measurement Device Model 7547 (SPMD Model 7547) has been designed and built for the purpose of measuring displacements and forces acting on the road wheels of a vehicle. These displacements and forces may be due to movement of the vehicle body (kinematic), forces occurring in the plane of the road (compliance), or due to movement of the steering wheel (steering). The SPMD Model 7547 tests the entire vehicle as a unit and provides a “black box” determination of the suspension characteristics in terms of input/output relationships. This data can then be used in the simulation of the performance of light cars and trucks.