scholarly journals An efficient and robust VUMAT implementation of elastoplastic constitutive laws in Abaqus/Explicit finite element code

2018 ◽  
Vol 19 (3) ◽  
pp. 308 ◽  
Author(s):  
Lu Ming ◽  
Olivier Pantalé
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Computational Time ◽  
Plastic Strain Rate ◽  
Integration Scheme ◽  
Elastoplastic Material ◽  
Finite Element Software ◽  
Return Mapping

This paper describes the development of an efficient and robust numerical algorithm for the implementation of elastoplastic constitutive laws in the commercial non-linear finite element software Abaqus/Explicit through a VUMAT FORTRAN subroutine. In the present paper, while the Abaqus/Explicit uses an explicit time integration scheme, the implicit radial return mapping algorithm is used to compute the plastic strain, the plastic strain rate and the temperature at the end of each increment instead of the widely used forward Euler approach. This more complex process allows us to obtain more precise results with only a slight increase of the total computational time. Corrector term of the radial return scheme is obtained through the implementation of a safe and robust Newton–Raphson algorithm able to converge even when the piecewise defined hardening curve is not derivable everywhere. The complete method of how to implement a user-defined elastoplastic material model using the radial return mapping integration scheme is presented in details with the application to the widely used Johnson–Cook constitutive law. Five benchmark tests including one element tests, necking of a circular bar and 2D and 3D Taylor impact tests show the efficiency and robustness of the proposed algorithm and confirm the improved efficiency in terms of precision, stability and solution CPU time. Finally, three alternative constitutive laws (the TANH, modified TANH and Bäker laws) are presented, implemented through our VUMAT routine and tested.

scholarly journals Inverse Strategies for Identifying the Parameters of Constitutive Laws of Metal Sheets

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
P. A. Prates ◽  
A. F. G. Pereira ◽  
N. A. Sakharova ◽  
M. C. Oliveira ◽  
J. V. Fernandes
Keyword(s):  
Finite Element ◽  
Cost Function ◽  
Optimization Algorithm ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Identification Procedure ◽  
Metal Sheets ◽  
The Cost

This article is a review regarding recently developed inverse strategies coupled with finite element simulations for the identification of the parameters of constitutive laws that describe the plastic behaviour of metal sheets. It highlights that the identification procedure is dictated by the loading conditions, the geometry of the sample, the type of experimental results selected for the analysis, the cost function, and optimization algorithm used. Also, the type of constitutive law (isotropic and/or kinematic hardening laws and/or anisotropic yield criterion), whose parameters are intended to be identified, affects the whole identification procedure.

Plastic Deformation Theory Application in Finite Element Analysis

2012 ◽  
Vol 594-597 ◽  
pp. 2723-2726
Author(s):  
Wen Shan Lin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Deformation Theory ◽  
Three Dimensional ◽  
Constitutive Laws ◽  
Constitutive Law ◽  
Element Analysis ◽  
Finite Element Program ◽  
Theory Of Plasticity ◽  
Element Program

In the present study, the constitutive law of the deformation theory of plasticity has been derived. And that develop the two-dimensional and three-dimensional finite element program. The results of finite element and analytic of plasticity are compared to verify the derived the constitutive law of the deformation theory and the FEM program. At plastic stage, the constitutive laws of the deformation theory can be expressed as the linear elastic constitutive laws. But, it must be modified by iteration of the secant modulus and the effective Poisson’s ratio. Make it easier to develop finite element program. Finite element solution and analytic solution of plasticity theory comparison show the answers are the same. It shows the derivation of the constitutive law of the deformation theory of plasticity and finite element analysis program is the accuracy.

Effect of Material Model on Finite Element Modeling of Aerospace Alloys

2013 ◽  
Vol 554-557 ◽  
pp. 151-156 ◽  
Author(s):  
Mehdi Saboori ◽  
Javad Gholipour ◽  
Henri Champliaud ◽  
Augustin Gakwaya ◽  
Jean Savoie ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Material Model ◽  
Constitutive Laws ◽  
Material Behavior ◽  
Constitutive Law ◽  
Expansion Process ◽  
Free Expansion ◽  
Element Modeling ◽  
Bulge Height

Increasing acceptance and use of hydroforming technology within the aerospace industry requires a comprehensive understanding of critical issues such as the material characteristics, friction condition and hydroformability of the material. Moreover, the cost of experiments that can be reduced by accurate finite element modeling (FEM), which entails the application of adapted constitutive laws for reproducing with confidence the material behavior. In this paper, the effect of different constitutive laws on FEM of tubular shapes is presented. The free expansion process was considered for developing the FEM. Bulge height, thickness reduction and strains were determined at the maximum bulge height using different constitutive models, including Hollomon, Ludwik, Swift, Voce, Ludwigson. In order to minimize the effect of friction, the free expansion experiments were performed with no end feeding. The simulation results were compared with the experimental data to find the appropriate constitutive law for the free expansion process.

scholarly journals Finite element modeling of sub-surface damage while machining aluminum based metal matrix composites

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110704
Author(s):  
Usama Umer ◽  
Hisham Alkhalefah ◽  
Mustufa Haider Abidi ◽  
Muneer Khan Mohammed ◽  
Hossam Kishawy
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Equivalent Plastic Strain ◽  
Surface Damage ◽  
Computational Time ◽  
Matrix Composites ◽  
Particle Fracture ◽  
Machined Surface

Sub-surface damage during machining of aluminum-based metal matrix composites (MMCs) has been modeled using finite element models. These models are based on reinforcement particles size and volume fractions and particles are distributed uniformly in the metal matrix. In order to simulate particle debonding cohesive zone elements (CZE) have been incorporated along the parting line. In addition, failure criteria based on brittle fracture have been added for ceramic particles to simulate particle fracture. To reduce computational time and simplify the model both CZE and particle fracture is limited to the reinforced particles along the parting lines facing the tip of the cutting tool. The damage depth beneath the machined surface is measured by using the non-zero plastic strain values in the equivalent plastic strain contours obtained from the FE models. The results were compared against published experimental data and found to be in good agreement.

The Comparison of the Criteria for Ratcheting in ASME VIII-2 and Methods Given by C-TDF

2020 ◽  
Author(s):  
Liping Wan ◽  
Wangping Dong
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Engineering Design ◽  
3D Structure ◽  
Three Dimensional ◽  
Element Analysis ◽  
Finite Element Software ◽  
Elastic Core ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract Ratcheting assessment by elastic-plastic stress analysis is presented in ASME VIII-2, paragraph 5.5.7. There are three criteria. The first one is strict in engineering design. It’s hard for most of structures to satisfy it. If the plastic strain in the structure is zero, it means that the material is not fully utilized and maybe the structure is unreasonable. Therefore, the second and third criteria are used much more. The first one and the third one can be observed directly and judged accurately by the finite element analysis results. The second one demands an elastic core in the primary-load-bearing boundary. It could be easily observed when the structure is axisymmetric, but hard to judge in the 3D structure. Okamoto in Committee on Three Dimensional Finite Element Stress Evaluation (C-TDF) has studied two thermal stress ratchet criteria: evaluating variations in the plastic strain increments and evaluating variations in the elastic core region, which can accurately assess ratcheting. Recent years, based on the criteria above, more researches have been performed by engineers not only from C-TDF but from all over the world. In this work, several two-dimensional structures and three-dimensional structures under particular load and displacement boundaries are performed by using finite element software ANSYS, aiming to compare the similarities and differences between the criteria in ASME VIII-2, 5.5.7.2 and those given by C-TDF. The assessment of these structures presented in this work will help engineers understand the realization of the criteria and methods in engineering design, especially how to utilize the results from ANSYS.

A Hardening Rule Between Stress Resultants and Generalized Plastic Strains for Thin Plates of Power-Law Hardening Materials

1993 ◽  
Vol 60 (2) ◽  
pp. 548-554 ◽  
Author(s):  
C. H. Chou ◽  
J. Pan ◽  
S. C. Tang
Keyword(s):  
Plastic Strain ◽  
Power Law ◽  
Potential Surface ◽  
Equivalent Stress ◽  
Yield Function ◽  
Constitutive Law ◽  
Thin Plates ◽  
Plastic Strain Rate ◽  
Hardening Rule ◽  
Stress Resultant

For power-law hardening materials, a stress resultant constitutive law of incremental plasticity nature for thin plates is constructed. The yield function in the stress resultant space is approximated in quadratic form and an equivalent stress resultant is defined. One of two parameters in the yield function is analytically determined based on the concept of complementary potential surface. The other is determined by the least square method to fit the complementary potential surface of Chou et al., (1991). In analogy to the work of Hill (1979), the equivalent work-conjugate generalized plastic strain rate is derived. Finally, the hardening rule between the equivalent stress resultant and generalized plastic strain is obtained based on the results of Chou et al. (1991) for power-law materials under proportional straining conditions.

Finite element analysis of the active element displacement in a giant magnetostrictive transducer

2016 ◽  
Vol 35 (4) ◽  
pp. 1371-1381 ◽  
Author(s):  
Dorota Stachowiak
Keyword(s):  
Finite Element ◽  
Mechanical Model ◽  
Active Element ◽  
Numerical Models ◽  
Symmetric Domain ◽  
Constitutive Law ◽  
Computational Time ◽  
Element Analysis ◽  
Content Type ◽  
Magnetostrictive Transducer

Purpose – The purpose of this paper is to find the method for determining the displacement of the active element in a giant magnetostrictive transducer. Design/methodology/approach – The giant magnetostrictive transducer with the active element made of Terfenol-D has been considered. A structure with an axisymmetrical transducer has been proposed. In the proposed model the coupling of magnetic and mechanical field has been taken into account. Maxwell’s equations for electromagnetics and Navier’s equations for mechanical systems are formulated in weak form and coupled using a nonlinear magneto-mechanical constitutive law for Terfenol-D. In order to obtain the distribution of the magnetic and mechanical fields the finite element method was used. The elaborated nonlinear magnetostrictive model has been implemented by using a finite element weak formulation with COMSOL Multiphysics. Findings – The elaborated model for the giant magnetostrictive transducer allows to take into account the magneto-mechanical coupling as well as the material’s nonlinearity. The calculation results of the strain distributions caused by magnetostrictive forces have been presented. The output displacement of a transducer vs supply current for different compressive preload stresses has been calculated and measured. The simulation and measurements results are in close agreement. Research limitations/implications – Taking advantage of the geometrical structure of the prototype of the giant magnetostrictive transducer the computations are performed in an axial-symmetric domain with cylindrical coordinates (r, z, ϑ). The axisymmetric formulation describes the giant magnetostrictive transducers (GMT) without significant loss of accuracy. This approach leads to smaller numerical models and reduced computational time. Practical implications – The elaborated magneto-mechanical model can be used to the design and optimize the structure of GMT. Originality/value – The paper offers the magneto-mechanical model of the giant magnetostrictive transducer. The elaborated model can predict behavior of the magnetostrictive materials it can be used as a tool for the design process of the giant magnetostrictive transducer.

scholarly journals Industrial Digital Twins based on the non-linear LATIN-PGD

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Philippe Barabinot ◽  
Ronan Scanff ◽  
Pierre Ladevèze ◽  
David Néron ◽  
Bruno Cauville
Keyword(s):  
Finite Element ◽  
High Performance ◽  
Reduced Order Modeling ◽  
Computational Time ◽  
Reduced Order ◽  
Finite Element Software ◽  
Digital Twins ◽  
Non Linear ◽  
Industrial Level ◽  
Early Design Phase

AbstractDigital Twins, which tend to intervene over the entire life cycle of products from early design phase to predictive maintenance through optimization processes, are increasingly emerging as an essential component in the future of industries. To reduce the computational time reduced-order modeling (ROM) methods can be useful. However, the spread of ROM methods at an industrial level is currently hampered by the difficulty of introducing them into commercial finite element software, due to the strong intrusiveness of the associated algorithms, preventing from getting robust and reliable tools all integrated in a certified product. This work tries to circumvent this issue by introducing a weakly-invasive reformulation of the LATIN-PGD method which is intended to be directly embedded into Simcenter Samcef$$^{\hbox {TM}}$$ TM finite element software. The originality of this approach lies in the remarkably general way of doing, allowing PGD method to deal with not only a particular application but with all facilities already included in such softwares—any non-linearities, any element types, any boundary conditions...—and thus providing a new high-performance all-inclusive non-linear solver.

Analyzing Fracture Behavior of Beam-Column Joints Using Micromechanical Fracture Models

2015 ◽  
Vol 744-746 ◽  
pp. 3-7
Author(s):  
Chen Zhang ◽  
Yu Ping Sun ◽  
Ju Tao Zhang ◽  
Yu Gu
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Fracture Behavior ◽  
Equivalent Plastic Strain ◽  
Stress Triaxiality ◽  
Bolted Connection ◽  
Finite Element Software ◽  
Maximum Value ◽  
Fracture Models ◽  
Welded Connection

The micromechanical fracture models were used to study the fracture behavior of the welded connection and welded-bolted connection joints. The Void Growth Model was implemented in commercial finite element software ABAQUS through the user-defined subroutines. The results predicted that cracks initiated at the edge of the welds and extended along the length and thickness of the welds. Comparing the effects of equivalent plastic strain and stress triaxiality for the fracture of the first failure element of both beam-to-column joints, we found that the equivalent plastic strain grew linearly as the loads increased and the weld of the lower flange generated cracks when the stress triaxiality increased at maximum value.

Effect of strut length and orientation on elastic mechanical response of modified body-centered cubic lattice structures

2019 ◽  
Vol 233 (11) ◽  
pp. 2219-2233 ◽  
Author(s):  
Hasanain S Abdulhadi ◽  
Ahsan Mian
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
Reference Model ◽  
Computational Time ◽  
Lattice Structures ◽  
Body Centered Cubic ◽  
Angle Variation ◽  
Fused Deposition ◽  
Finite Element Software ◽  
Wide Range

Lattice structures (LSs) have been exploited for wide range of applications including mechanical, thermal, and biomedical structures because of their unique attributes combining the light weight and high strength. The main goal of this research is to investigate the effect of strut length and orientation on the mechanical characteristics of modified body-centered cubic (BCC) LS subjected to a quasi-static axial compressive loading within linear elastic limit using finite element analysis. In this study, two sets of LS were built and analyzed in commercial finite element software, ABAQUS/CAE/EXPLICIT 6.16, using a “smart procedure,” which was developed for this research to reduce the computational time and increase the accuracy of results by creating hexahedral mesh elements. The first set comprises 13 models having fixed strut length with strut angle variation from 40° to 100° with a step of 5°. The second set also includes 13 models; however, having variant strut length, kept constant for a single unit cell and through the entire model but varied from one model to another, with the same strut angle variation as the first set. In addition, the BCC LS with a strut angle of 70.53° was replicated in both sets because it was considered as a reference model to compare the results with it. Furthermore, specimens of the reference model were fabricated by a fused deposition modeling- (FDM) based 3D printer using acrylonitrile butadiene styrene (ABS) material and tested experimentally under compression. Experimental results are observed to be in good agreement with those of the finite element simulation, hence the same loading and boundary conditions were adopted for all other models. It was observed that the fixed strut length BCC LS with a strut angle of 100° offers the highest modulus. However, the highest specific strain energy absorption and specific stiffness as well as the least value of weight were dictated by a variant strut length BCC LS with a strut angle of 40°.

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