Development of a MADYMO3D Model of the SID-IIs Dummy

1999 ◽  
Author(s):  
D. Para V. Weerappuli ◽  
Li Chai ◽  
Saeed Barbat ◽  
Deborah Wan ◽  
Priya Prasad
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Elastic Material ◽  
Rigid Wall ◽  
Side Impact ◽  
Test Results ◽  
Lumped Mass ◽  
Material Models ◽  
Hybrid Iii ◽  
Using Data

Abstract This paper describes the development of a mathematical model of the new small-sized side impact dummy, SID-IIs. The model, utilizing both lumped-mass and finite element methods of analysis, was developed using the commercially-available software MADYMO3D. As the SID-IIs dummy is based on a 12–13 year-old adolescent/5th percentile female, the head, neck, pelvis, and lower extremities were taken from MADYMO3D lumped-mass models of the Hybrid-III 5th percentile female dummy. The shoulder rib, the three thoracic ribs, the two abdominal ribs, and the foam insert in the dummy jacket were modeled using the finite element method. The ribs were characterized using elastic and visco-elastic material models. The foam insert and the jacket were modeled using foam and elastic material models, respectively. The visco-elastic and foam material constants were determined using data from dynamic tests and an optimization scheme based on the “Box” iteration method. Preliminary validations of the model were carried out at both sub-assembly and fully-assembled dummy levels. At the sub-assembly level, test results of blunt impacts on the isolated thorax were compared with model results. At the fully-assembled dummy level, data from verification pendulum tests and rigid-wall sled tests were compared with model results. Generally, for all validation simulations, the model predictions of rib displacements and accelerations showed good agreement with corresponding test results during the loading phase. During unloading, however, there were discrepancies between test data and model results. Additionally, for the rigid wall tests, head acceleration, neck moment, and pelvic acceleration compared well with test data. Overall, the predicted responses provide a reasonable level of confidence in the fidelity of the model.

Computational Human Torso Model Validation for Frontal Blunt Trauma

2018 ◽  
Author(s):  
Carolyn E. Hampton ◽  
Michael Kleinberger
Keyword(s):  
Finite Element ◽  
Blunt Trauma ◽  
Energy Absorption ◽  
Elastic Material ◽  
Peak Force ◽  
Tissue Type ◽  
Absorption Data ◽  
Element Analysis ◽  
Material Models ◽  
Torso Model

Recent research on behind-armor blunt trauma (BABT) has focused on the personal protection offered by lightweight armor. A finite element analysis was performed to improve the biofidelity of the US Army Research Laboratory (ARL) human torso model to prepare for simulating blunt chest impacts and BABT. The overly stiff linear elastic material models for the torso were replaced with material characterizations drawn from current literature. FE torso biofidelity was determined by comparing peak force, force-compression, peak compression, and energy absorption data with cadaver responses to a 23.5 kg pendulum impacting at the sternum at 6.7 m/s. Nonlinear foam, viscous foam, soft rubbers, fibrous hyperelastic rubbers, and low moduli elastic material were considered as material models for the flesh, organs, and bones. Simulations modifying one tissue type revealed that the flesh characterization was most crucial for predicting compression and force, followed closely by the organs characterizations. Combining multiple tissue modifications allowed the FE torso to mimic the cadaveric torsos by reducing peak force and increasing chest compression and energy absorption. Limitations imposed by the Lagrangian finite element approach are discussed with potential workarounds described. Proposed future work is split between considering additional impact scenarios accounting for position and biomaterial variability.

scholarly journals Biaxial estimation of biomechanical constitutive parameters of passive porcine sclera soft tissue

2021 ◽  
Author(s):  
Zwelihle Ndlovu ◽  
Dawood Desai ◽  
Thanyani Pandelani ◽  
Harry Ngwangwa ◽  
Fulufhelo Nemavhola
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Model ◽  
Test Data ◽  
Element Model ◽  
Finite Element Models ◽  
Anisotropic Model ◽  
Material Models ◽  
Material Parameters ◽  
Constitutive Parameters

This study assesses the modelling capabilities of four constitutive hyperplastic material models to fit the experimental data of the porcine sclera soft tissue. It further estimates the material parameters and discusses their applicability to a finite element model by examining the statistical dispersion measured through the standard deviation. Fifteen sclera tissues were harvested from porcine’ slaughtered at an abattoir and were subjected to equi-biaxial testing. The results show that all the four material models yielded very good correlations at correlations above 96 %. The polynomial (anisotropic) model gave the best correlation of 98 %. However, the estimated material parameters varied widely from one test to another such that there would be needed to normalise the test data to avoid long optimisation processes after applying the average material parameters to finite element models. However, for application of the estimated material parameters to finite element models, there would be needed to consider normalising the test data to reduce the search region for the optimisation algorithms. Although the polynomial (anisotropic) model yielded the best correlation, it was found that the Choi-Vito had the least variation in the estimated material parameters thereby making it an easier option for application of its material parameters to a finite element model and also requiring minimum effort in the optimisation procedure. For the porcine sclera tissue, it was found that the anisotropy more influenced by the fiber-related properties than the background material matrix related properties.

The Influence of Material Models on Finite Element Simulation of Machining

2004 ◽  
Vol 126 (4) ◽  
pp. 849-857 ◽  
Author(s):  
Jing Shi ◽  
C. Richard Liu
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Power Law ◽  
Cutting Forces ◽  
Temperature Effects ◽  
Test Results ◽  
Material Models ◽  
Orthogonal Machining ◽  
Element Simulation ◽  
Selection Of

In literature, four models incorporating strain rate and temperature effects are able to generalize material test results of HY-100 steel. This study compares the four models, namely, Litonski-Batra, power law, Johnson-Cook, and Bodner-Partom, in finite element modeling of orthogonal machining of this material. Consistency is found in cutting forces, as well as in stress and temperature patterns in all but the Litonski-Batra model. However, the predicted chip curls are inconsistent among the four models. Furthermore, the predicted residual stresses are substantially sensitive to the selection of material models. The magnitudes, and even the sign of the residual stresses in machined surfaces, vary with different models.

Modeling of the Rate Responsive Behavior of Elastomer Foam Materials

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Feixia Pan
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Test Data ◽  
Experimental Test ◽  
Strain Rates ◽  
Foam Material ◽  
Material Models ◽  
Rate Dependent ◽  
Responsive Behavior ◽  
Rate Responsive

Elastomer foam materials are shock absorbers that have been extensively used in applications of electronic packaging. Finite element modeling simulation plays an important role in helping the designers determine the best elastomer foam material and the best structure of a shock absorber. Elastomer foam materials have very complicated material behaviors. The prediction of the rate responsive behavior is one of the most interesting topics in elastomer material modeling. The focus of this article is to present a unique method for deriving the rate dependent constitutive model of an elastomer foam based on the extension of the Cowper and Symond law and the curve fitting on experimental test data. The research on rate dependent material models and the material models available in commercially available finite element analysis software have been reviewed. Test data collection at various strain rates has been discussed. Two steps of curve fitting on experimental test data are used to retrieve analytical expression of the constitutive model. The performance of the constitutive model for a foam material has been illustrated and shown to be quite good. This method is easy to understand and the simple formulation of the constitutive model is very suitable for applications in numerical simulation. The constitutive model could be used to predict the stress-strain curves of a foam material at any strain rate, especially at the intermediate strain rates, which are the most difficult to collect so far. In addition, this model could be readily integrated with the hyperelastic material models to more efficiently evaluate the mechanical behavior of an elastomer foam material. The model could potentially be implemented in commercially available software such as ABAQUS and LS-DYNA. The method presented is also useful in deriving constitutive models of rubberlike elastomer materials.

Finite Element Modeling of Tire With Validation Using Tensile and Frequency Response Testing

2014 ◽  
Author(s):  
Jennifer M. Bastiaan ◽  
Amir Khajepour
Keyword(s):  
Finite Element ◽  
Uniaxial Tension ◽  
Material Model ◽  
Element Model ◽  
Test Results ◽  
Material Models ◽  
Modal Damping ◽  
Hyper Elastic ◽  
Response Testing ◽  
Tread Rubber

A physical testing program is performed in support of finite element model creation for a 50-series passenger car tire. ABAQUS finite element analysis software is used along with its standard material models. Uniaxial tension testing of tire samples cut from the tread composite, tread rubber and sidewall composite is performed in order to obtain material properties. Hyper-elastic material coefficients for tread rubber are fit using uniaxial tension test data. Results show that the Arruda-Boyce hyper-elastic material model fits the test data well and it predicts reasonable overall behavior in uniaxial tension and uniaxial compression. Most other hyperelastic material models are found to predict unrealistic behavior in uniaxial compression for the tire samples, especially in the 0 to 20% compressive strain range. Frequency response testing of two inflated passenger car tires of different sizes, makes and models is also performed to assist in defining the viscoelastic material model for tread rubber. Test results show that tire modal damping is in the 2 to 4% range for most modes below 200 Hz, and the response curves, modal density and modal damping are remarkably similar for the two tires tested. The tire finite element model with updated material properties is simulated for nine combinations of air inflation pressure and vertical load in order to calculate static loaded radius. The analysis results are compared with physical test results and the analysis results are found to deviate at most by 3% compared to the tests.

A Comparative Study of Valve Natural Frequency Estimation Using Finite Element Analysis (FEA), Raleigh’s Principles and Laboratory Tests

2014 ◽  
Author(s):  
L. Ike Ezekoye ◽  
Preston A. Vock ◽  
Ronald S. Farrell ◽  
Richard J. Gradle
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
The Other ◽  
Test Results ◽  
Lumped Mass ◽  
Element Analysis ◽  
Valve Body ◽  
Other Hand

The natural frequency of valves is an important design requirement to ensure that valves do not go into resonance during operation and consequently fail structurally or fail to perform their design and safety related functions. Besides its impact on operability, valve resonance can initiate piping vibration that could damage pipes and their supports; which is undesirable. As important as equipment natural frequency is to valve operability, one would expect that testing should be the de facto method for confirming its value. Ideally, this should be the case, however, cost considerations limit the extent to which testing is used. On the other hand, testing does have some issues with respect to accuracy such as the effect of supporting structure flexibility resulting in a conservatively lower natural frequency measurement. In addition, the multiplicity of valves in nuclear power plants with different designs, sizes and safety classes limit the use of testing to establish valve natural frequencies except when required in the equipment specifications. Frequently, valve natural frequencies are determined by analysis either using finite element techniques (FEA) or by first principles of beam and mass models; the latter being more frequently used. This paper presents the studies performed to correlate valve natural frequency test results to the results derived from analytical techniques using Raleigh’s energy principle and from finite element analysis (FEA) methods. In a previous paper on valve natural frequency [1], Ezekoye et al. presented a model for estimating valve natural frequency by incorporating mass inertia of the valve structures with the more traditional methods that are based on a lumped mass model to determine displacements. In the process, the flexibility of the extended structure (otherwise referred to as the superstructure) and the valve body itself are considered. Using limited test data, Ezekoye et al. showed that there is merit in using their enhanced analysis model. Their correlation was promising. The finite element analysis, on the other hand, is a well-established technique for solving complex structural mechanics problems and should be expected to provide reasonable results comparable to actual valve tests provided the boundary conditions provide a reasonable representation of the actual valves tested. In this paper, ANSYS Version 12.1 was used to model valve natural frequencies. Additionally, a more extensive testing of valves for natural frequency was performed in this paper than was reported in Reference 1. The results of both the FEA and the Raleigh’s principle model as presented in Ezekoye et al. are compared against the test results. By comparing the three results, strengths and weaknesses of each method become apparent. The choice of whether or not one chooses to test or perform analysis depends on the valve specification requirement and the preference of the designer.

Experimental and Numerical Study for Determining the Mechanical Properties of Automobile Weatherstrip Seals

2006 ◽  
Author(s):  
Emre Dikmen ◽  
Ipek Basdogan
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Test Data ◽  
Compression Test ◽  
Strain Energy ◽  
Energy Functions ◽  
Material Models ◽  
Compression Load ◽  
Hyperelastic Materials ◽  
Strain Energy Functions

Structural parts made of hyperelastic materials such as rubber mounts in automotive powertrains and weatherstrip seals are widely used in automotive and other engineering applications. In this study, compression load deflection (CLD) behavior of a highly non-linear type of joint, automotive weatherstrip seal made of Ethylene Propylene Diene Monomer (EPDM) sponge rubber is examined using finite element modeling techniques. The finite element modeling (FEM) results are then compared with the compression load deflection data obtained experimentally. The compression load deflection data for various punch velocities can be used to model the weatherstrip seal as a nonlinear spring-dashpot system with varying stiffness and damping coefficient proportional to the amount of compression. The weatherstrip seals should be modeled accurately in order to predict the dynamic performance of the automobiles under various load conditions. First part of the study includes modeling of the seal using various hyperelastic material models which are available in ANSYS. The strain energy functions’ coefficients required for the various material models are calculated using both linear and nonlinear least square fit procedures implemented in ANSYS for fitting the tension, shear and compression test data. After the coefficients are calculated, the compression test is performed in ANSYS using various hyperelastic material models. Second part of the study includes the compression experiment of weatherstrip seal with a robotic indenter specifically designed for measuring hyperelastic materials. The measured CLD data is then compared with the FEM results. The accuracy of using only simple tension test data to acquire the coefficients for strain energy functions is investigated and suitable strain energy functions to model compression of weatherstrip seal are determined. Additionally, Mullins Effect (stress softening) for this application is investigated using the compression experiments data.

Finite Element Modeling and Simulation of Inflatable Tubular Structure Airbag

2001 ◽  
Author(s):  
Tarek A. Omar ◽  
Wolfgang Rehm ◽  
Nabih E. Bedewi ◽  
Ali Al-Fraiji
Keyword(s):  
Finite Element ◽  
Head And Neck ◽  
Element Model ◽  
Tubular Structure ◽  
Side Impact ◽  
Fe Model ◽  
Life Saving ◽  
Hybrid Iii ◽  
Head Injury Criteria ◽  
Impact Simulations

Abstract The Inflatable Tubular Structure (ITS) airbag is a potentially life-saving device that has been implemented recently in some luxury passenger vehicles. When deployed, the ITS-airbag provides primarily protection of the front seat occupant’s head and face against upper side-interior car components. In the current research, a nonlinear Finite Element (FE) model for ITS-airbag system was proposed, developed, and tested in a side impact using dummy-head and neck FE model. The modeling technique of the unique behavior of the outer layer of the ITS-airbag is explained in details. Modeling such a complicated behavior of the ITS (axial shrinkage and radial expansion) was successfully performed by using a combination of diagonal truss elements combined with an isotropic fabric material. Nonlinear FE side-impact simulations for a Hybrid-III dummy-head and neck model impacting a vehicle’s side glassing, roof-rail, and B-pillar using the ITS airbag system were conducted using the explicit FE code LS-DYNA. The developed ITS model has reduced the Head Injury Criteria (HIC) and the peak-acceleration of the dummy-head significantly. The results indicated the ability of the developed finite element model to represent the real ITS airbag system and therefore provide a reliable nonlinear FE simulation results that could be used to test, improve, and validate the implementation of the ITS airbag systems in more vehicles.

scholarly journals Rail Passenger Equipment Collision Tests: Analysis of Structural Measurements

2000 ◽  
Author(s):  
Kristine J. Severson ◽  
David C. Tyrell ◽  
A. Benjamin Perlman
Keyword(s):  
Test Data ◽  
Failure Modes ◽  
Lateral Displacement ◽  
Rigid Wall ◽  
Crash Test ◽  
Lumped Mass ◽  
Passenger Cars ◽  
Passenger Rail ◽  
Rail Vehicles ◽  
Protection Strategies

Abstract A two-car full-scale collision test was conducted on April 4, 2000. Two coupled rail passenger cars impacted a rigid wall at 26 mph. The cars were instrumented with strain gauges, accelerometers, and string potentiometers, to measure the deformation of critical structural elements, the longitudinal, vertical, and lateral car body accelerations, and the displacements of the truck suspensions. Instrumented crash test dummies were also tested in several seat configurations, with and without lap and shoulder belts. The objectives of the two-car test were to measure the gross motions of the car, to measure the force/crush characteristic, to observe the car-to-car interaction, to observe failure modes of the major structural components, and to evaluate selected occupant protection strategies. The measurements taken during the test were used to refine and validate existing computer models of conventional passenger rail vehicles. This test was the second in a series of collision tests designed to characterize the collision behavior of rail vehicles. The two-car test resulted in approximately 6 feet of deformation at the impacting end of the lead vehicle, and a few inches of deformation at the coupler. The cars remained coupled, but buckled in a saw-tooth mode, with a 15-inch lateral displacement between the cars after the test. The test data from the two-car test compared favorably with data from the single-car test, and with analysis results developed with a lumped-mass computer model. The model is described in detail. The methods of filtering and interpreting the test data are also included.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

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