Comparison between elastic and porous elastic material models for sediment acoustical behavior in an aluminum-sediment double layer

2021 ◽  
Vol 43 (5) ◽  
Author(s):  
Omid Bahrami Khameslouie ◽  
Mohammad Hossein Soorgee ◽  
Ehsan Ghafarallahi ◽  
Seyed Ebrahim Moussavi Torshizi
Keyword(s):  
Double Layer ◽  
Elastic Material ◽  
Material Models

scholarly journals On the thermodynamics of pseudo-elastic material models which reproduce the M ullins effect

2015 ◽  
Vol 69-70 ◽  
pp. 360-369 ◽  
Author(s):  
Christoph Naumann ◽  
Jörn Ihlemann
Keyword(s):  
Elastic Material ◽  
Material Models

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 Minimizing Residual Stress in Brazed Joints by Optimizing the Brazing Thermal Profile

2020 ◽  
Author(s):  
Ben Mann ◽  
Kurtis Ford ◽  
Mike Neilsen ◽  
Dan Kammler
Keyword(s):  
Elastic Material ◽  
Curie Point ◽  
Thermal Strain ◽  
Optimization Techniques ◽  
Filler Materials ◽  
Thermal Profile ◽  
Slow Cooling ◽  
Element Analysis ◽  
Material Models ◽  
Cooling Rates

Abstract Ceramic to metal brazing is a common bonding process used in many advanced systems such as automotive engines, aircraft engines, and electronics. In this study, we use optimization techniques and finite element analysis utilizing viscoplastic and thermo-elastic material models to find an optimum thermal profile for a Kovar® washer bonded to an alumina button that is typical of a tension pull test. Several active braze filler materials are included in this work. Cooling rates, annealing times, aging, and thermal profile shapes are related to specific material behaviors. Viscoplastic material models are used to represent the creep and plasticity behavior in the Kovar® and braze materials while a thermo-elastic material model is used on the alumina. The Kovar® is particularly interesting because it has a Curie point at 435°C that creates a nonlinearity in its thermal strain and stiffness profiles. This complex behavior incentivizes the optimizer to maximize the stress above the Curie point with a fast cooling rate and then favors slow cooling rates below the Curie point to anneal the material. It is assumed that if failure occurs in these joints, it will occur in the ceramic material. Consequently, the maximum principle stress of the ceramic is minimized in the objective function. Specific details of the stress state are considered and discussed.

Elastic Material Models

2012 ◽  
pp. 183-213
Author(s):  
Franco M. Capaldi
Keyword(s):  
Elastic Material ◽  
Material Models

Verification of the elastic material characteristics of Norway spruce and European beech in the field of shear behaviour by means of digital image correlation (DIC) for finite element analysis (FEA)

Holzforschung ◽  
2017 ◽  
Vol 71 (5) ◽  
pp. 405-414 ◽  
Author(s):  
Jaromír Milch ◽  
Martin Brabec ◽  
Václav Sebera ◽  
Jan Tippner
Keyword(s):  
Finite Element Analysis ◽  
Elastic Material ◽  
Numerical Models ◽  
European Beech ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Data Sets ◽  
Element Analysis ◽  
Material Models ◽  
Material Characteristics

Abstract Norway spruce (Picea abies L. Karst.) and European beech (Fagus sylvatica L.) samples were loaded in shear mode aimed at testing their elastic material characteristics applicable in finite element analysis (FEA). More precisely, experimental and numerical analyses of uniaxial tensile test parallel to grain in longitudinal-radial (LR) or longitudinal-tangential (LT) shear of plane are described. The elastic material models in the FEA are based on own experimental data and those of the literature. The verification of material characteristics was performed by 3D numerical models with the same parameters as for the experimental tests. The fully orthotropic elastic material model was applied in the uniaxial tensile tests. The digital image correlation (DIC) method served for verification of the numerical models with proposed elastic material characteristics. Good correlation was found between numerically predicted and experimentally measured data. The minor differences between the two data sets could be mainly attributed to certain natural wood characteristics, which were neglected in the proposed models, i.e. especially variation of earlywood and latewood density. The proposed elastic material models offer general data sets for the evaluation of mechanical response of timber structures and especially in timber connexions.

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.

Modelling a Liquid Material in Drop Test Simulations of a Cask for Liquid Radioactive Waste

2014 ◽  
Vol 611 ◽  
pp. 145-155
Author(s):  
Vladimír Ivančo ◽  
Martin Orečný
Keyword(s):  
Elastic Material ◽  
Equations Of State ◽  
Liquid Radioactive Waste ◽  
Drop Test ◽  
Computational Time ◽  
Energy Agency ◽  
Material Models ◽  
Lagrange Formulation ◽  
Liquid Material ◽  
Explicit Dynamic

The aim of this paper is the comparison of different material models for the simulation of fluid impact on a cask for transport of radioactive liquid material. Simulated is a 9 m drop test performed according to International Atomic Energy Agency regulations. In order to reduce computational time, proposed is to model the transported fluid as a hypothetic linearly elastic material. This enables us to use less time demanding FE explicit dynamic analysis based on Lagrange formulation only instead of combination of Lagrange and Euler formulations. Compared are the results obtained for three elastic material and three fluid models based on different equations of state.

scholarly journals New numerical stress solutions to calibrate hyper-visco-pseudo-elastic material models effectively

2020 ◽  
Vol 194 ◽  
pp. 108861
Author(s):  
Bálint Fazekas ◽  
Tibor J. Goda
Keyword(s):  
Elastic Material ◽  
Material Models
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