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EuroSID-2 and EuroSID-2re are among the most frequently used side impact dummies in vehicle crash safety. Radioss is one of most widely applied finite element codes for crash safety analysis. To meet the needs of crash safety analysis and to exploit the potential of the Radioss code, a new generation of EuroSID-2 (ES2) and EuroSID-2re (ES2_RE) Radioss dummies was developed at First Technology Safety System (FTSS) in collaboration with Altair. This paper describes in detail the development of the ES2/ES2_RE dummies. Firstly whole dummy meshes were created based on CAD data and intensive efforts were made to obtain penetration/intersection-free models. Secondly FTSS finite element certificate tests at component level were conducted to obtain satisfactory component performances. These tests include the head drop test, the neck pendulum test, the lumbar pendulum test and the thorax drop test [ 1 , 2 ].

Finite element simulation of air bags as part of the automotive occupant restraint system is rapidly evolving as a new CAE tool in support of car product development. The majority of occupant computer simulations are concentrated around the study of occupant impact into the air bag when the air bag is substantially inflated. Further, the initial air bag representation in the simulation prior to deployment is of an unfolded configuration. These simplifications do not compromise simulation of crashes wherein the dummy comes in contact with the air bag after it is substantially full. The situation wherein the dummy interacts with the air bag early during the inflation is of interest when the occupant is located close to the air bag prior to deployment. In such cases the predeploy-ment geometry of the air bag in the model needs to be representative of the actual air bag folded configuration and the unfolding of the air bag needs to be simulated.

A PC based interactive program was developed to simulate the unfolding and deploying process of a driver side airbag in the sagittal plane. The airbag was represented by a series of nodes. The maximum allowable stretch was less or equal to one between any two nodes. We assumed that the airbag unfolding was pivoted about folded points. After the completion of the unfolding process the airbag would begin to deploy. During the deploying process, two parameters were used to determine the nodal priority of the inflation. The first parameter was the distance between the instantaneous and final positions of a node. Nodes with longer distances to travel will have to move faster. We also considered the distance between the current nodal position and the gas inlet location. For a node closer to the gas inlet, we assumed that the deploying speed was faster. A graphical procedure was used to calculate the area of the airbag.

This paper describes the development of new advanced Finite Element (FE) models of the World SID series, namely World SID 50th and 5th, the new generation of side impact Anthropomorphic Test Devices (ATD). The model development follows the FTSS's rigorous quality assurance (QA) procedure and uses the manufacture's product data and test facilities extensively. The models are validated at material, component & assembly, full dummy certification and sled test application levels. A detailed modeling methodology is described. The models correlate well with both the component and whole dummy level test results.

This research focuses on the response of the Q3, Hybrid III 3-year-old dummy and a child finite element model in a simulated 213 sled test. The Q3 and Hybrid III 3-year old child finite element models were developed by First Technology Safety Systems. The 3-year-old child finite element model was developed by Nagoya University by model-based scaling from the AM50 (50 percentile male) total human model for safety. The child models were positioned in a forward facing, five-point child restraint system using Finite Element Model Builder. An acceleration pulse acquired from an experimental 213 sled test, which was completed following the guidelines outlined in the Federal Motor Vehicle Safety Standard 213 using a Hybrid III 3-year-old dummy, was applied to the seat buck supporting the child restraint seat. The numerical simulations utilizing the Q3, Hybrid III 3-year-old and the child finite element model were conducted using the explicit non-linear finite element code LS-DYNA.

This study identified the mechanical properties of ten cadaveric lumbar spines and two Hybrid III lumbar spines. Eight tests were performed on each specimen: tension, compression, anterior shear, posterior shear, left lateral shear, flexion, extension and left lateral bending. Each test was run at a displacement rate of 100 mm/sec. The maximum displacements were selected to approximate the loading range of a 50 km/h Hybrid III dummy sled test and to be non-destructive to the specimens. Load, linear displacement and angular displacement data were collected. Bending moment was calculated from force data. Each mode of loading demonstrated consistent characteristics. The load-displacement curves of the Hybrid III lumbar spine demonstrated an initial region of high stiffness followed by a region of constant stiffness.

A three-dimensional finite element model of a human neck has been developed in an effort to study the mechanics of cervical spine while subjected to impacts. The neck geometry was obtained from MRI scans of a 50th percentile male volunteer. This model, consisting of the vertebrae from C1 through T1 including the intervertebral discs and posterior elements, was constructed primarily of 8-node brick elements. The vertebrae were modeled using linear elastic-plastic materials, while the intervertebral discs were modeled using linear viscoelastic materials. Sliding interfaces were defined to simulate the motion of synovial facet joints. Anterior and posterior longitudinal ligaments, facet joint capsular ligaments, alar ligaments, transverse ligaments, and anterior and posterior atlanto-occipital membranes were modeled as nonlinear bar elements or as tension-only membrane elements. A previously developed head and brain model was also incorporated.

The modular dummy model is a new concept to represent a crash dummy in computer simulation. The modular dummy model could be a solution with combination of acceptable responses and quick run times. The approach of the modular dummy model is to take an existing standard model and create rigid modules of all major dummy components (Head, Thorax, Pelvis, Femurs, Tibias, Feet, etc.), which are fully interchangeable between deformable and rigid modules. The special run time efficient component models for the neck and lumbar spine are also developed for the modular dummy. Mass and inertial properties of each rigid module are derived from the corresponding deformable part. The joint and connection definitions are shared between the rigid and deformable modules. The users only need to decide and select which modules should be used in order to achieve the best compromise between CPU time and accuracy for the specific application.

Lower extremity injuries in frontal automotive crashes usually occur with footwell intrusion where both the knee and foot are constrained. In order to identify factors associated with tibial shaft injury, a series of numerical simulations were conducted using a finite element model of the whole human body. These simulations demonstrated that tibial mid-shaft injuries in frontal crashes could be caused by an abrupt change in velocity and a high rate of footwell intrusion.

A nonlinear foam was added to a previously created three-dimensional finite element model of the Hybrid III dummy chest which consisted of six steel ribs, rib damping material, the sternum, a spine box and a pendulum. Two standard calibration pendulum impact tests for a Hybrid III dummy chest were used to validate the new model. An explicit finite element analysis code PAM-CRASH was utilized to simulate the dynamic process. At impact velocities of 6.7 m/s and 4.3 m/s, the force and deflection time history as well as the force-deflection plots showed good agreement between model predictions and calibration data. Peak strains also agreed well with experimental data.

Various types of padding have been used in side impact sled tests with cadavers. This paper presents a summary of performance of the padding used in NHTSA and WSU/CDC sled tests, and a summary of material properties of padding used in cadaveric sled tests. The purpose of this paper is to provide information on padding performance in cadavers, rather than optimum padding performance in dummies.

Heidelberg-type side impact sled tests were conducted using SID side impact dummies. These tests were run under similar conditions to a series of cadaveric sled tests funded by the Centers for Disease Control in the same lab. Tests included 6.7 and 9 m/s (15 and 20 mph) unpadded and 9 m/s padded tests. The following padding was used at the thorax: ARSAN, ARCEL, ARPAK, ARPRO, DYTHERM, 103 and 159 kPa (15 and 23 psi) crush strength paper honeycomb, and an expanded polystyrene. In all padded tests the dummy Thoracic Trauma Index, TTI(d) was below the value of 85 set by federal rulemaking (49 CFR, Part 571 et al., 1990). In contrast, cadavers in 9 m/s sled tests did not tolerate ARSAN 601 (MAIS 5) and 23 psi (159 kPa) paper honeycomb (MAIS 5), and 20 psi (138 kPa) Verticel™ honeycomb (MAIS 4), but tolerated 15 psi (103 kPa) paper honeycomb (average thoracic MAIS 2.3 in six tests).

Accurate prediction of the responses from the anthropomorphic test devices (ATDs) in vehicle crash tests is critical to achieving better vehicle occupant performances. In recent years, automakers have used finite element (FE) models of the ATDs in computer simulations to obtain early assessments of occupant safety, and to aid in the development of occupant restraint systems. However, vehicle crash test results have variation, sometimes significant. This presents a challenge to assessing the accuracy of the ATD FE models, let alone improving them. To resolve this issue, it is important to understand the test variation and carefully select the target data for model improvement. This paper presents the work carried out by General Motors and Humanetics Innovative Solutions (formerly FTSS) in a joint project, aimed at improving the FE model of the Hybrid III-50 ATD (HIII-50) v5.1.

Auto racing has been in vogue from the time automobiles were first built. With the dawn of modern cars came higher engine capacities; the speeds involved in these races and crashes increased as well. However, the advent of passive restraint systems such as the helmet, HANS (Head and Neck Support device), multi-point harness system, roll cage, side and frontal crush zones, racing seats, fire retardant suits, and soft-wall technology, have greatly improved the survivability of the drivers in high-speed racing crashes. Three left lateral crashes from Begeman and Melvin (2002), Case #LAS12, #IND14 and #99TX were used as inputs to the Wayne State Human Body Model (WSHBM) in a simulated racing buck. Twelve simulations with delta-v, six-point harness and shoulder pad as design variables were analyzed for the average maximum principal strain (AMPS) in the aorta. The average AMPS for the high-speed crashes were 0.1551±0.0172 while the average maximum pressure was 110.50±4.25 kPa.

Twelve side impact sled tests were performed using a horizontally accelerated sled and a Heidelberg-type seat fixture. In these tests the subject's whole body impacted a sidewall with one of three surface conditions: 1) a flat, rigid side wall, 2) a side wall with a 6″ pelvic offset, or 3) a flat, padded side wall. This series of runs provided a good test of how injury criteria perform under a variety of impact surface conditions. In this study thoracic injury criteria based on force, acceleration, compression, and velocity x compression (VC) were evaluated. Maximum compression and VCmax proved to be the best injury indicators in this series. Biomechanical response and injury tolerance are also presented.

In the automotive seating industry measurements of lumbar support prominence and height are performed to assess their effects on occupant comfort. This project investigated measurement methods for lumbar support prominence and height in an occupied seat. Fifteen participants provided subjective responses of their perceived lumbar support prominence and height utilizing specifically developed visual analog scales. Also, pressure measurements were taken while the participants were seated. The recently developed H-point manikin II was utilized as a standardized sitter. Specifically, the lumbar support prominence (LSP) measure was used for the prominence measures. Pressure mat readings with the seated manikin was used for lumbar support height determination and prominence correlations. With both manikin and participants in the seat, the lumbar support was digitized through the rear of the seat.

In occupant safety simulations it is desirable to extend existing rigid body occupant models towards deformable Finite Element models. Thereby a wider range of occupant / structure interactions can be covered and a better accuracy can be achieved. This paper describes some aspects of the FE modelling of the EUROSID thorax for use in an explicit Finite Element code. First a single rib model is evaluated, then a full thorax is generated and inserted into a rigid body Dummy model. Experimental results from impactor tests serve as a basis for the validation of the model.

A three-dimensional finite element model of the Hybrid III dummy head-neck complex was created to simulate the Amended Part 572 Head-Neck Pendulum Compliance Test, of the Code of Federal Regulations. The model consisted of a rigid head and five circular aluminum disks joined together by butyl elastomer rubber. Contact surfaces were defined to allow the anterior neck to separate upon an application of extension moments. Two mounting positions, one for flexion and the other one for extension, were used to simulate the head-neck calibration tests. An explicit finite element code PAM-CRASH was utilized to simulate the model dynamic responses. Simulation results were compared to experimental data obtained from First Technology Safety Systems Inc. Model predictions agreed well in both flexion and extension. This model can be used to study the head-neck biomechanics of the existing dummy as well as in the development of new dummies.

Thirty-seven SID side impact sled tests were performed using a rigid wall and a padded wall with fourteen different padding configurations. The Thoracic Trauma Index (TTI) and Average Spine Acceleration (ASA) were measured in each test. TTI and ASA were evaluated in terms of their ability to predict injury in identical cadaver tests and in terms of their ability to predict the harm or benefit of padding of different crush strengths. SID ASA predicted the injury seen in WSU-CDC cadaver tests better than SID TTI. SID ASA predicted that padding of greater than 20 psi crush strength is harmful (ASA > 40 g's). SID TTI predicted that padding of greater than 20 psi crush strength is beneficial (TTI < 85 g's). SID TTI predicts the benefit of lower impact velocity. However, SID ASA appears more useful in assessing the harm or benefit of door padding or air bags.

Numerical simulation of the airbag can be used as a powerful tool in the development of a SIR (Supplemental Inflatable Restraint) system leading to an optimized design and to reduce the development time. However, modeling flattened or folded airbags from the 3D CAD geometry and simulating exact airbag shapes during the deployment is a very complex problem. Especially for the passenger side airbags, generating a flattened and folded mesh from the CAD geometry of the airbag is a very difficult task as these airbags are made of non-developable surface and can not be flattened easily without introducing secondary folds, wrinkling or distortions of mesh. A novel approach called as Initial Metric methodology effectively addresses these problems. The initial metric method uses two types of meshes, A CAD reference mesh and a mapped or a scaled (compressed) mesh constructed from a CAD mesh of the airbag. In the simulation, mapped or scaled (compressed) mesh is used for airbag inflation.