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The SAE Large Male and Small Female Dummy Task Group has recommended a change to the Hybrid III dummy hip joint. This change was made because of a non-biofidelic interference in the current design that can influence chest accelerations. The modifications include a new femur casting shaft design and the addition of an elastomeric stop to the top of the casting. Static testing and Hyge sled tests were done to evaluate the modifications. Based on the results, the new design satisfied the requirements set by the SAE task group and reduced the influence of hip joint characteristics on chest accelerations.

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.

The design of the Hybrid III dummy's hip joint limits the allowable relative rotation between the dummy's lower torso and femur assembly. This limited motion is thought to cause abnormally high chest accelerations in some front barrier crash tests. This paper describes static testing and computer modeling to quantify the hip joint range of motion and its effect on dummy chest accelerations. To verify model results, a series of HYGE sled tests were completed using modified hip joints.

The potential of head injury in frontal barrier impact tests was investigated by a mathematical model which consisted of a finite element human head model, a four segments rigid dynamic neck model, a rigid body occupant model, and a lumped-mass vehicle structure model. The finite element human head model represents anatomically an average adult head. The rigid body occupant model simulates an average adult male. The structure model simulates the interior space and the dynamic characteristics of a vehicle. The neck model integrates the finite element human head to the occupant body to give a more realistic kinematic head motion in a barrier crash test. Model responses were compared with experimental cadaveric data and vehicle crash data for the purpose of model validation to ensure model accuracy. Model results show a good agreement with those of the tests.

Topology optimization is used for obtaining the best layout of vehicle structural components to achieve predetermined performance goals. Unlike the most common approach which uses the optimality criteria methods, the topology design problem is formulated as a general optimization problem and is solved by the mathematical programming method. One of the major advantages of this approach is its generality; thus it can solve various problems, e.g. multi-objective and multi-constraint problems. The MSC/NASTRAN finite element code is employed for response analyses. Two automotive examples including a simplified truck frame and a truck frame crossmember are presented.

A tunable stamped collector was developed to improve vehicle performance, drive-by noise and subjective noise quality, and reduced thermal stress concentrations. The stamped collector is located at the junction of the legs of the down pipe/catalytic converter assembly for a transverse mounted V-6 engine and acts to equalize the leg length of the down pipe, as well as provide acoustic tuning volume. This collector differs from most other methods to equalize leg lengths on transverse mounted engines in that it has a tuning chamber incorporated into the design itself, which allows for specific noise frequencies to be reduced. Performance characteristics were measured for a conventional down-pipe and the stamped collector using the following analysis techniques: Frequency analysis of tailpipe noise emissions. Drive-by noise emissions. Horsepower measurements using an engine dynamometer.

The regulated and non-regulated emissions of a current diesel passenger car and two light-duty diesel trucks with catalysts and particulate traps were measured to better understand the effects of aftertreatment devises on the environment. The passenger car, a 1.8 L IDI TC Sierra, was tested both with and without three different diesel oxidation catalysts (DOC) and with two fuel sulfur levels, 0 and 0.05 wt%. One light-duty truck, a 2.5 L DI NA Transit, was tested on one fuel, 0.05 wt% sulfur, with and without three different particulate trap/regeneration systems and with and without a urea lean NOx catalyst (LNC) system. A second similar Transit was tested on the 0.05 wt% sulfur fuel with an electrically regenerated trap system. The results are compared to each other, regulated emission standards, and to emissions from gasoline vehicles.

This paper first describes an experimental analytical approach and numerical procedures used to establish crushable foam material constants needed in finite element (FE) analysis. Dynamic compressive stress-strain data of a 2 pcf Dytherm foam, provided by ARCO Chemical, is used to determine the material parameters which appears in the foam constitutive equation. A finite element model simulating a 15 mph spherical headform impact with a foam sample 6 in. x 6 in. x 1 in. fixed against a rigid plate is developed. The predicted force-deflection characteristic is validated against test data to characterize the initial loading and final unloading stiffnesses of the foam during impact. Finite element modeling and analysis of 15 mph spherical headform impact with component sections of upper interior structures of a passenger compartment is presented.

In vehicle crash tests, an unbelted occupant's kinetic energy is absorbed by the restraints such as an air bag and/or knee bolster and by the vehicle structure during occupant ride-down with the deforming structure. Both the restraint energy absorbed by the restraints and the ride-down energy absorbed by the structure through restraint coupling were studied in time and displacement domains using crash test data and a simple vehicle-occupant model. Using the vehicle and occupant accelerometers and/or load cell data from the 31 mph barrier crash tests, the restraint and ride-down energy components were computed for the lower extremity, such as the femur, for the light truck and passenger car respectively.

The design and composition of heat shields is becoming a major factor in the design of future automobiles. The optimization of heat insulation materials is crucial in keeping size, mass, and cost to a minimum. The purpose of this paper is to describe the testing of four different fibrous insulating materials simulating 150,000 miles of the Underbody heat shielding that a light duty truck may experience. The materials were tested before and after the thermal durability experiment to show the degraded conduction performance of each sample.

The European safety regulation plan regarding frontal barrier offset impact calls for 30° angular impact protection in 1995 and a perpendicular 40% offset deformable barrier impact protection in the 1998 time frame. However, various other governmental and private agencies are looking at alternative test conditions. The Auto Motor and Sport Magazine and other insurance agencies have been conducting rigid barrier front impact tests at 40 and 50% offsets. In this study various test conditions were examined analytically. Detailed finite element models were developed to understand the implications of these impact conditions. The models provided insight into energy management mechanism, load transfer and vehicle deformation patterns due to offset impacts on to perpendicular and angular barriers. Several potential offset conditions were simulated using the FEA models.

Due to several indeterminate factors, the assessment of the durability performance of a vehicle body is traditionally accomplished using test methods. An analytical fatigue life prediction method (four-step durability process) that relies mainly on numerical techniques is described in this paper. The four steps comprising this process include the identification of high stress regions, recognizing the critical load types, determining the critical road events and calculation of fatigue life. In addition to utilizing a general purpose finite element analysis software for the application of the Inertia Relief technique and a previously developed fatigue analysis program, two customized programs have been developed to streamline the process into an integrated, user-friendly tool. The process is demonstrated using a full body, finite element model.

This paper reports the analytical procedure developed for a simulation of knee impact during a barrier crash using a hybrid III dummy lower torso. A finite element model of the instrument panel was generated. The dummy was seated in mid-seat position and was imparted an initial velocity so that the knee velocity at impact corresponded to the secondary impact velocity during a barrier crash. The procedure provided a reasonably accurate simulation of the dummy kinematics. This simulation can be used for understanding the knee bolster energy management system. The methodology developed has been used to simulate impact on knee for an occupant belted or unbelted in a frontal crash. The influence of the vehicle interior on both the dummy kinematics and the impact locations was incorporated into the model. No assumptions have been made for the knee impact locations, eliminating the need to assume knee velocity vectors.

A series of tests were conducted to determine the potential for reducing vehicle underhood temperatures by either 1) diverting the radiator fan air flow from the engine compartment or 2) by forced air cooling of the exhaust manifold in conjunction with shielding it or 3) by a combination of the two methods. The test vehicle was a Ford F-250 Light Truck with a 7.5L V-8 engine. The vehicle was tested in a dynamometer cell equipped with cell blowers to simulate road speed conditions. It was found that diverting the outlet air from the radiator will reduce underhood component temperatures when the vehicle is in motion and also at normal idle. However, if the vehicle is to be used for power takeoff applications requiring a “kicked” idle, then forced cooling of the exhaust manifolds is also required to maintain reduced underhood temperatures. A combination of these two techniques maximized the reduction of underhood temperatures for all operating conditions tested.

The evolution of computer technology has made CAE ( Computer Aided Engineering ) an integral part of the total vehicle development process. Particularly for crash development, up-front input is crucial in determining vehicle architecture, performing trade off studies and setting design targets. Detailed FEA ( Finite Element Analysis ), although more accurate, is not always suitable at this stage due to (1) the lack of Detailed design information and (2) the large amount of modelling and analysis efforts. Concept/Hybrid models, however, can provide important input to make early design decisions without a detailed design. This paper uses a concept model to illustrate the above mentioned point. The model contains, the interior structure of a pick-up truck, driver occupant, restraints, and a detailed steering column assembly. Correlation with a physical test demonstrates the reliability of the model. Several restraint parameters which influence occupant performance are identified.

This paper describes an investigation into the sound quality of passenger car and light truck closure sounds. The closure sound events that were studied included side doors, hoods, trunklids, sliding doors, tailgates, liftgates, and fuel filler doors. Binaural recordings were made of the closure sounds and presented to evaluators. Both paired comparison of preference and semantic differential techniques were used to subjectively quantify the sound quality of the acoustic events. Major psychoacoustic characteristics were identified, and objective measures were then derived that were correlated to the subjective evaluation results. Regression analysis was used to formulate models which can quantify customers perceptions of the sounds based on the objectively derived parameters. Many times it was found that the peak loudness level was a primary factor affecting the subjective impression of component quality.

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.

While evaluating the BIOSID advanced side impact dummy in full scale crash tests, we noticed higher than expected abdominal rib deflections. This finding led to a search to determine whether these deflections were an artifact of the dummy or whether the dummy was indicating that some portion of the vehicle side, in the area of the armrest, was laterally stronger than expected. Many armrests/trim panels were procured and both quasi-statically and dynamically tested using newly-devised test procedures. A team was formed to evaluate armrest/trim panel construction and to develop a biomechanically-based laboratory test procedure to help determine the effects of design and material changes. This team continues to function and a spin-off team is seeking to develop analytical predictive tools to allow speedier development of armrest/trim panels attuned to the new test procedure.

One of the major goals in the design of the new Ford Aeromax and Louisville heavy truck product line was to achieve competitive leadership in visibility. Market research found that visibility was an important issue to the heavy truck driver. Visibility is defined as both direct and indirect (i.e., the driver's ability to see with and without the use of supplemental vision devices such as mirrors) and both interior and exterior. The scope of this paper includes the work which was accomplished in evaluating direct and indirect exterior visibility and the resulting vehicle design which achieved Ford's leadership goals. Poor weather visibility and interior vision are beyond the scope of this paper. Polar Plots were the method of choice in the Aeromax/Louisville visibility studies. Industry acceptance of these techniques has been established in the recent approval of SAE J1750, “Evaluating the Truck Driver's Viewing Environment”.