Development of Constitutive Equation for Infinite Body of Impact Problem

2007 ◽  
Vol 353-358 ◽  
pp. 611-614
Author(s):  
Seung Yong Yang
Keyword(s):  
Finite Element ◽  
Constitutive Equation ◽  
Plane Waves ◽  
Shear Plane ◽  
Material Behavior ◽  
Infinite Body ◽  
Wave Impact ◽  
Finite Element Software ◽  
Impact Simulations ◽  
Impact Problem

A constitutive equation was developed for an infinite body in plane wave impact problem, and implemented using the finite element software ABAQUS user subroutine. Bilinear material behavior under monotonically increasing loading was considered for the constitutive equation. The finite element governed by this type of material behavior can be used as an infinite body transmitting longitudinal and shear plane waves, so that the number of finite elements can be reduced in impact simulations. To test the developed method, results of a plate impact experiment were examined. The numerical results show the accuracy of the developed constitutive equation.

scholarly journals Finite Element Software for Rubber Products Design

2018 ◽  
Vol 3 (1) ◽  
pp. 13-20
Author(s):  
Dávid Huri
Keyword(s):  
Finite Element ◽  
Complex Analysis ◽  
Large Deformations ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Material Models ◽  
Finite Element Software ◽  
Highly Nonlinear ◽  
Wide Range ◽  
Different Types

Automotive rubber products are subjected to large deformations during working conditions, they often contact with other parts and they show highly nonlinear material behavior. Using finite element software for complex analysis of rubber parts can be a good way, although it has to contain special modules. Different types of rubber materials require the curve fitting possibility and the wide range choice of the material models. It is also important to be able to describe the viscoelastic property and the hysteresis. The remeshing possibility can be a useful tool for large deformation and the working circumstances require the contact and self contact ability as well. This article compares some types of the finite element software available on the market based on the above mentioned features.

scholarly journals Thermo-Mechanical Modeling of Distortions Promoted during Cooling of Ti-6Al-4V Part Produced by Superplastic Forming

2016 ◽  
Vol 838-839 ◽  
pp. 196-201
Author(s):  
Maxime Rollin ◽  
Vincent Velay ◽  
Luc Penazzi ◽  
Thomas Pottier ◽  
Thierry Sentenac ◽  
...  
Keyword(s):  
Finite Element ◽  
Thermal Stresses ◽  
Superplastic Forming ◽  
Model Material ◽  
Material Behavior ◽  
Mechanical Modeling ◽  
Temperature Dependent ◽  
Finite Element Software ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

In AIRBUS, most of the complex shaped titanium fairing parts of pylon and air inlets are produced by superplastic forming (SPF). These parts are cooled down after forming to ease their extraction and increase the production rate, but AIRBUS wastes a lot of time to go back over the geometric defects generated by the cooling step. This paper investigates the simulations of the SPF, cooling and clipping operations of a part on Abaqus® Finite element software. The different steps of the global process impact the final distortions. SPF impacts the thickness and the microstructure/behavior of material, cooling impacts also the microstructure/behavior of material and promotes distortions through thermal stresses and finally, clipping relaxes the residual stresses of the cut part. An elastic-viscoplastic power law is used to model material behavior during SPF and a temperature dependent elastic perfectly plastic model for the cooling and clipping operations.

scholarly journals Study of Parameters during Aluminum Cutting with Finite Element Method

2020 ◽  
Vol 64 (2) ◽  
pp. 136-144
Author(s):  
János György Bátorfi ◽  
Mátyás Andó
Keyword(s):  
Finite Element ◽  
Shear Plane ◽  
Material Model ◽  
Tool Geometry ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Finite Element Software ◽  
Cutting Velocity ◽  
Deform 2D ◽  
Cutting Model

The authors analyzed the force and stress values in the simplified cutting model and compared the results with the literature. For the study a 2D model was created in DEFORM 2D finite element software, using the temperature depended multilinear flow stress material model. The model was compiled according to the literatures. In this analysis were the effects of relief angel, tool angle, tool radius, depth of cut, and the cutting velocity examined. The values of forces, strain, temperature, stress and shear plane angle were examined at different values of geometry and machining parameters. For these examinations were used 28 parameter combinations. As a result of the study, the results for forces are similar to the results of examined literature at every parameter. The force results were checked on a simple tool geometry.

The Effect of the Variation in ACL Constitutive Model on Joint Kinematics and Biomechanics Under Different Loads: A Finite Element Study

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Chao Wan ◽  
Zhixiu Hao ◽  
Shizhu Wen
Keyword(s):  
Finite Element ◽  
Constitutive Equation ◽  
Constitutive Model ◽  
Constitutive Models ◽  
Transversely Isotropic ◽  
Joint Kinematics ◽  
Material Behavior ◽  
Ground Substance ◽  
Anterior Tibial ◽  
Hyperelastic Model

The biomechanics and function of the anterior cruciate ligament (ACL) have been widely studied using both experimental and simulation methods. It is known that a constitutive model of joint tissue is a critical factor in the numerical simulation. Some different ligament constitutive models have been presented to describe the ACL material behavior. However, the effect of the variation in the ligament constitutive model on joint kinematics and biomechanics has still not been studied. In this paper, a three-dimensional finite element model of an intact tibiofemoral joint was reconstructed. Three ACL constitutive models were compared under different joint loads (such as anterior tibial force, varus tibial torque, and valgus tibial torque) to investigate the effect of the change of the ACL constitutive model. The three constitutive models corresponded to an isotropic hyperelasticity model, a transversely isotropic hyperelasticity model with neo-Hookean ground substance description, and a transversely isotropic hyperelastic model with nonlinear ground substance description. Although the material properties of these constitutive equations were fitted on the same uniaxial tension stress-strain curve, the change of the ACL material constitutive model was found to induce altered joint kinematics and biomechanics. The effect of different ACL constitutive equations on joint kinematics depended on both deformation direction and load type. The variation in the ACL constitutive models would influence the joint kinematic results greatly in both the anterior and internal directions under anterior tibial force as well as some other deformations such as the anterior and medial tibial translations under valgus tibial torque, and the medial tibial translation and internal rotation under varus torque. It was revealed that the transversely isotropic hyperelastic model with nonlinear ground substance description (FE model III) was the best representation of the realistic ACL property by a linear regression between the simulated and the experiment deformation results. But the comparison of the predicted and experiment force of ligaments showed that all the three ACL constitutive models represented similar force results. The stress value and distribution of ACL were also altered by the change in the constitutive equation. In brief, although different ACL constitutive models have been fitted using the same uniaxial tension curve and have the similar longitudinal material property, the ACL constitutive equation should still be carefully chosen to investigate joint kinematics and biomechanics due to the different transverse material behavior.

The Finite Element Analysis of the Column of Wave-Power Generating Device

2012 ◽  
Vol 614-615 ◽  
pp. 546-549
Author(s):  
Yan Jun Liu ◽  
Xing Wang Sun ◽  
Bo Zheng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Impact Force ◽  
Safety Performance ◽  
Wave Power ◽  
Wave Load ◽  
Wave Impact ◽  
Element Analysis ◽  
Finite Element Software ◽  
The Finite Element Analysis

The columnof the wave-power generating device is analysed through theoretical analysis using finite element software. The deformation and stress under maximum wave impact force is calculated by harmonic analysis, the result of which indicates that deformation and stress of the maincolumn, which under huge wave impact calculated by Morison theory, is very small. The stress of the column generated by wave load is less than its material yield strength, which indicates that the safety performance meets the requirements.

Finite Element Analysis of Optimum Back Pressure during Equal Channel Angular Pressing

2008 ◽  
Vol 575-578 ◽  
pp. 311-315
Author(s):  
Feng Jian Shi ◽  
Lei Gang Wang
Keyword(s):  
Finite Element ◽  
Equal Channel Angular Pressing ◽  
Effective Strain ◽  
Back Pressure ◽  
Material Behavior ◽  
Element Analysis ◽  
Die Geometry ◽  
Fine Grained ◽  
Finite Element Software ◽  
Angular Pressing

Equal channel angular pressing (ECAP) is one of the most promising processes to fabricate ultra-fine grained materials. The material deformation is affected by die geometry, material behavior, friction and back pressure. The optimum back pressure for 1100Al during ECAP was studied. The effect of back pressure on deformation behavior, effective strain and deformation load were analyzed by using finite element software. The results show that the corner gap between the billet and the die in the external part of the deformation zone decreases and even disappears with the increase of back pressure, which can produce more uniform and larger strain in the billet. The deformation load enhances with the increase of back pressure. From the simulation results, it can be found out that the optimum back pressure for 1100Al pressed in the die of Φ=90° is about 30MPa.

scholarly journals NUMERICAL MODELLING OF THE AIRFRAME DAMAGE GROWTH FOR THE ADHESIVE REPAIR JOINT CALCULATION

2018 ◽  
Vol 21 (3) ◽  
pp. 125-138
Author(s):  
A. A. Fedotov ◽  
A. V. Tsipenko ◽  
A. I. Lebedev
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Information Technologies ◽  
Mechanical Response ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Fatigue Properties ◽  
Damage Growth ◽  
Finite Element Software ◽  
Software Packages

In the context of the predicted growth in air transportation, the additional attention will be paid to the organization of the competitive maintenance and repair operations for the commercial airplanes. The implementation of new technological processes for airframe repairs and the application of modern information technologies during the development of the repair procedures can be a significant advantage in the expanding market of post-production support of the commercial air fleet. Airframe adhesive repairs allow using lifting abilities of the materials more intensively, but application of the adhesive joints technology requires more complicated strength calculation procedure. It is advisable to utilize the modern finite element software packages to perform the reliable calculation. The capabilities of these software packages allow obtaining adequate computational results for adhesive repair joint parameters subjected to cyclic loads. This paper is concentrated on application of the finite element methods to simulate the crack growth in isotropic material and on methods for accelerated calculation of the mechanical response of cracked structures. Crack growth simulation is performed based on XFEM methods where the created finite element model is complemented with asymptotic imitation function of crack tip and with discontinuous jump function across the crack surfaces. Fatigue properties of the repair joint are modelled in accordance with direct cyclic approach, where a Fourier series approximation with time integration of the nonlinear material behavior is applied. After that, the result of integration at each point of the load history is used for the prediction of the material fatigue properties degradation at the next step of computation; this allows us to evaluate the material damage growth rate. Based on calculation results, a conclusion was made that the received numerical data match the full-scale test results; the time spent for calculation with the usage of accelerated computational methods was evaluated. 

APPLICATION OF SYNTHETIC FIBER ROPES TO REDUCE BLAST RESPONSE OF A PORTAL FRAME

2006 ◽  
Vol 06 (04) ◽  
pp. 513-526 ◽  
Author(s):  
M. R. MOTLEY ◽  
R. H. PLAUT
Keyword(s):  
Finite Element ◽  
Large Deformations ◽  
Material Behavior ◽  
Synthetic Fiber ◽  
Plastic Strains ◽  
Finite Element Software ◽  
Stiffness Coefficients ◽  
Blast Response ◽  
Portal Frame ◽  
Relationship Of

A steel portal frame subjected to an external blast is analyzed. The use of diagonal synthetic fiber ropes to brace the frame is studied. The force-elongation relationship of the ropes when in tension is modeled either as a bilinear function with initial slackness, or a power law based on tests. The effect of the ropes in reducing deflections and plastic strains is determined using the finite element software ABAQUS/Explicit. Inclusion of the influence of strain-rate on the material behavior of the frame is important. Several blast magnitudes and rope stiffness coefficients are considered. Snap loads occur in the ropes if the blast is sufficiently large. Deformations and strains may be reduced significantly by the ropes, and failure may be prevented.

scholarly journals Low-Cycle Fatigue Crack Initiation Simulation and Life Prediction of Powder Superalloy Considering Inclusion-Matrix Interface Debonding

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4018
Author(s):  
Shuming Zhang ◽  
Yuanming Xu ◽  
Hao Fu ◽  
Yaowei Wen ◽  
Yibing Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Crack Initiation ◽  
Life Prediction ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Fatigue Crack Initiation ◽  
Fatigue Loading ◽  
Interface Debonding ◽  
Damage Evolution Equation ◽  
Finite Element Software

From the perspective of damage mechanics, the damage parameters were introduced as the characterizing quantity of the decrease in the mechanical properties of powder superalloy material FGH96 under fatigue loading. By deriving a damage evolution equation, a fatigue life prediction model of powder superalloy containing inclusions was constructed based on damage mechanics. The specimens containing elliptical subsurface inclusions and semielliptical surface inclusions were considered. The CONTA172 and TARGE169 elements of finite element software (ANSYS) were used to simulate the interfacial debonding between the inclusions and matrix, and the interface crack initiation life was calculated. Through finite element modeling, the stress field evolution during the interface debonding was traced by simulation. Finally, the effect of the position and shape size of inclusions on interface debonding was explored.

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