scholarly journals A Design Optimization Study for the Die Dimensioning Using the Locking Nut Folding Simulation

2021 ◽  
Vol 71 (2) ◽  
pp. 41-52
Author(s):  
Bozkurt Ülüver ◽  
Kacar İlyas
Keyword(s):  
Inverse Analysis ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Dimensional Accuracy ◽  
Optimization Method ◽  
Nonlinear Material ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Hardening Rule ◽  
Highly Nonlinear

Abstract An inverse analysis based on optimization process is performed to determine die curvatures for a locking nut’s flange folding process which has highly nonlinear material behaviour. The nut material is AISI C1040 steel. The ring material is polyamide 6. The Chaboche’s nonlinear kinematic hardening rule is combined with bilinear isotropic hardening model as a hardening rule for the plasticity model combined with associated flow rule and von Mises yield criterion. The inverse analysis is applied to determine the curvatures by using genetic algorithm optimization method based on dimensional accuracy. The optimum mould curvatures are determined. So a comprehensive methodology is presented for determination of curvatures.

Descriptions of Reversed Yielding in Internally Pressurized Tubes

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Sergei Alexandrov ◽  
Woncheol Jeong ◽  
Kwansoo Chung
Keyword(s):  
Yield Criterion ◽  
Numerical Technique ◽  
Kinematic Hardening ◽  
Material Model ◽  
Flow Rule ◽  
Hardening Material ◽  
Hardening Law ◽  
Solving Equations ◽  
Associated Flow Rule ◽  
Reversed Deformation

Using Tresca's yield criterion and its associated flow rule, solutions are obtained for the stresses and strains when a thick-walled tube is subject to internal pressure and subsequent unloading. A bilinear hardening material model in which allowances are made for a Bauschinger effect is adopted. A variable elastic range and different rates under forward and reversed deformation are assumed. Prager's translation law is obtained as a particular case. The solutions are practically analytic. However, a numerical technique is necessary to solve transcendental equations. Conditions are expressed for which the release is purely elastic and elastic–plastic. The importance of verifying conditions under which the Tresca theory is valid is emphasized. Possible numerical difficulties with solving equations that express these conditions are highlighted. The effect of kinematic hardening law on the validity of the solutions found is demonstrated.

scholarly journals A New 3D Empirical Plastic and Damage Model for Simulating the Failure of Concrete Structure

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Yan-tao Jiao ◽  
Bo Wang ◽  
Zhen-zhong Shen
Keyword(s):  
Damage Mechanics ◽  
Evolution Equations ◽  
Influence Factor ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Damage Model ◽  
Nonlinear Behavior ◽  
Complex Stress State ◽  
Flow Rule ◽  
Wide Range

Abstract A new plastic–damage constitutive model based on the combination of damage mechanics and classical plastic theory was developed to simulate the failure of concrete. In order to explain different material behaviors of concrete under tensile and compressive loadings, the plastic yield criterion, the different kinematic hardening rule for tension and compressive and the isotropic flow rule were established in the effective stress space. Meanwhile, two different empirical damage evolution equations were adopted: one for compression and the other for tension. A multi-axial damage influence factor was also introduced to fully describe the anisotropic damage of concrete. Finally, the model response was compared with a wide range of experiment results. The results showed that the model could well describe the nonlinear behavior of concrete in a complex stress state.

Advanced High Strength Steel Sheet Forming and Springback Simulation

2010 ◽  
Vol 97-101 ◽  
pp. 200-203 ◽  
Author(s):  
Ke Chen ◽  
Jian Ping Lin ◽  
Mao Kang Lv ◽  
Li Ying Wang
Keyword(s):  
High Strength Steel ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Sheet Material ◽  
High Strength ◽  
Material Model ◽  
Sheet Forming ◽  
Isotropic Hardening ◽  
Advanced High Strength Steel ◽  
Springback Prediction

With the increasing use of finite element analysis method in sheet forming simulations, springback predictions of advanced high strength steel (AHSS) sheet are still far from satisfactory precision. The main purpose of this paper was to provide a method for accurate springback prediction of AHSS sheet. Material model with Hill’48 anisotropic yield criterion and nonlinear isotropic/kinematic hardening rule were applied to take account the anisotropic yield behavior and the Bauschinger effect during forming processes. U-channel forming and springback simulation was performed using ABAQUS software. High strength DP600 sheet was investigated in this work. The simulation results obtained with the proposed material model agree well with the experimental results, which show a remarkable improvement of springback prediction compared with the commonly used isotropic hardening model.

Experimental and Numerical Study of Uniaxial and Multiaxial Stress-Strain Behaviour of R7T Wheel Steel

2015 ◽  
Vol 732 ◽  
pp. 91-94 ◽  
Author(s):  
Radim Halama ◽  
Michal Šofer ◽  
František Fojtík ◽  
Aleksandros Markopoulos
Keyword(s):  
Numerical Study ◽  
Kinematic Hardening ◽  
Wheel Steel ◽  
Isotropic Hardening ◽  
Good Prediction ◽  
Main Attention ◽  
Stress Strain ◽  
Strain Behavior ◽  
Hardening Rule ◽  
Strain Behaviour

This paper is focused on the correct description of stress-strain behavior of the R7T steel. An experimental study on the wheel steel specimens including uniaxial as well as multiaxial tests has been conducted. The main attention was paid to such effects as ratcheting and nonproportional hardening of the material. A cyclically stable behavior of the steel under higher amplitude loading was found. The MAKOC model, which is based on AbdelKarim-Ohno kinematic hardening rule and Calloch isotropic hardening rule, has been applied in subsequent finite element simulations. The numerical results show very good prediction of stress-strain behaviour of the wheel steel.

A nonlinear simulation of a bi-failure specimen through improved discretisation methods: A validation study

2018 ◽  
Vol 53 (8) ◽  
pp. 616-629 ◽  
Author(s):  
Behzad V Farahani ◽  
Jorge Belinha ◽  
Paulo J Tavares ◽  
Pedro MGP Moreira
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Numerical Study ◽  
Interpolation Method ◽  
Yield Criterion ◽  
Image Correlation ◽  
Uniaxial Tensile ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Nonlinear Simulation

A robust and efficient scheme is rendered to elastoplastically study the material nonlinearity of structural components. In this investigation, a specimen manufactured from the aluminium alloy AA6061-T6 is considered. It is mechanically loaded under a uniaxial tensile state and the experimental strain datum is analysed by three-dimensional digital image correlation. Due to specific specimen geometry, complex stress states will occur. However, the specimen yields due to an approximated uniaxial stress state. The obtained remote stress/strain from experimental data is used to validate the computational solutions using advanced discretisation approaches. Therefore, as a preliminary numerical study, the model is simulated through the finite element method formulation. Afterwards, another numerical strategy is adopted – the radial point interpolation method. The Newton–Raphson initial stiffness method is thereby adapted to complete the nonlinear solutions algorithm. Furthermore, the elastoplastic demeanour of aluminium alloys is determined with the von Mises yield criterion, an isotropic hardening rule and an associative flow rule. Obtained computational results fit the experimental digital image correlation solution, which allow to conclude that the proposed meshless methodology is efficient and reliable.

The Study of Elastic-Plastic Fatigue Behavior of Nigerian-Rolled NST 37-2 Steel

2010 ◽  
Vol 3 ◽  
pp. 28-41
Author(s):  
B.O. Malomo ◽  
S.A. Ibitoye ◽  
L.O. Adekoya
Keyword(s):  
Numerical Study ◽  
Plastic Material ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Fatigue Behavior ◽  
Numerical Results ◽  
Test Material ◽  
Flow Rule ◽  
Static Fatigue ◽  
Elastic Plastic

The NST 37-2 steel represents about 75% volume of Nigerian-produced steel which is yet to be fully characterized for its fatigue behavior. Thus, its suitability for many applications is questionable. This paper presents a framework based on the theory of elasto-plasticity in order to make appropriate recommendations in this regard. Experimentally, tensile tests were carried out on test specimens to establish the baseline material properties of the steel in annealed, as-rolled, normalized and hardened/tempered conditions. Fatigue tests were then conducted at 60% Su; 70% Su and 80% Su of the test material and fractographic examinations on the test specimens were subsequently carried out. The frequency harmonic fatigue analysis was implemented in the ANSYS software environment for the numerical study. The elastic-plastic material property was described by the von Mises yield criterion, the flow rule of Prandtl-Reuss, and the kinematic hardening rule of Prager. The numerical results indicate with respect to rate-dependence fatigue behavior that the annealed test specimen is most resilient under cyclic deformation as compared with the normalized, hardened/tempered and as-rolled specimens respectively. The experimental and numerical results were found to be in close agreement and based on the general performance, the steel material is recommended for use in low cycle, quasi-static fatigue applications.

scholarly journals On finite element implementation of cyclic elastoplasticity: theory, coding, and exemplary problems

2021 ◽  
Author(s):  
Cyprian Suchocki
Keyword(s):  
Finite Element ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Small Strain ◽  
Cyclic Plasticity ◽  
Isotropic Hardening ◽  
Mapping Algorithm ◽  
Hardening Rule ◽  
Return Mapping ◽  
Cyclic Plasticity Model

AbstractIn this work the finite element (FE) implementation of the small strain cyclic plasticity is discussed. The family of elastoplastic constitutive models is considered which uses the mixed, kinematic-isotropic hardening rule. It is assumed that the kinematic hardening is governed by the Armstrong–Frederick law. The radial return mapping algorithm is utilized to discretize the general form of the constitutive equation. A relation for the consistent elastoplastic tangent operator is derived. To the best of the author’s knowledge, this formula has not been presented in the literature yet. The obtained set of equations can be used to implement the cyclic plasticity models into numerous commercial or non-commercial FE packages. A user subroutine UMAT (User’s MATerial) has been developed in order to implement the cyclic plasticity model by Yoshida into the open-source FE program CalculiX. The coding is included in the Appendix. It can be easily modified to implement any isotropic hardening rule for which the yield stress is a function of the effective plastic strain. The number of the utilized backstress variables can be easily increased as well. Several validation tests which have been performed in order to verify the code’s performance are discussed.

A Constitutive Model with Effect of Temperature for Frozen Soil

2014 ◽  
Vol 919-921 ◽  
pp. 627-631 ◽  
Author(s):  
Xiang Tian Xu ◽  
Cai Xia Fan ◽  
Tian Yu Zhang
Keyword(s):  
Constitutive Model ◽  
Yield Criterion ◽  
Frozen Soil ◽  
Effect Of Temperature ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Model Coupling ◽  
Hardening Law ◽  
Different Temperatures ◽  
Temperature Variable

To model the stress-strain relation of frozen soil under different temperatures, an elasto-plastic constitutive model coupling with temperature variable was proposed. Under axisymmetric condition, elastic strain was calculated by the K-G model coupling with temperature. The plastic strain was calculated by using the DP yield criterion, associated flow rule and isotropic hardening law. All of the elastic and plastic parameters are related to the temperature variable. The simulated results show that the proposed model can predict the deformation behavior of frozen soil under different temperatures.

Geometric and Material Nonlinear Analyses of a Heated Zigzag Pipeline: Case Study to Look for High Stress Situations

2006 ◽  
Author(s):  
Adilson Carvalho Benjamin ◽  
Rita de Ca´ssia Carvalho Silva ◽  
Joa˜o Nisan Correia Guerreiro ◽  
Abimael Fernando Dourado Loula
Keyword(s):  
Yield Criterion ◽  
High Stress ◽  
General Purpose ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Nonlinear Analyses ◽  
Hardening Rule ◽  
Von Mises ◽  
Material Nonlinear

This paper describes the case study performed to look for high stress situations that may occur along the life span of a heated zigzag pipeline. The main results of several finite element (FE) analyses are presented. These analyses were performed using the general purpose FE program ABAQUS considering geometric and material nonlinearities. A rate-independent plasticity model using the von Mises yield criterion and isotropic hardening rule were adopted.

An Analysis of the Yield Criteria and the Stress-Strain Relationships of a Pre-Strained Commercially Pure Aluminium

1978 ◽  
Vol 20 (4) ◽  
pp. 169-175 ◽  
Author(s):  
G. H. Daneshi
Keyword(s):  
Yield Criterion ◽  
Stress Path ◽  
Isotropic Hardening ◽  
Pure Aluminium ◽  
Stress Strain ◽  
Yield Criteria ◽  
Hardening Rule ◽  
Commercially Pure ◽  
Deviatoric Plane ◽  
Strain Trajectory

An analysis of the stress path and the strain trajectory of a pre-strained engineering material in the deviatoric plane is presented. The deviatoric stress vector, which for a pre-strained material is initially at an angle to the strain trajectory, is shown to coincide with it after the ‘recoverable’ energy is consumed. Experimental work is carried out on the yield criteria and the stress—strain relationships of a pre-strained commercially pure aluminium. The significance of the isotropic hardening rule in relation to a metal's straining memory is demonstrated. It is shown that beyond a stress level associated with an isotropic hardening rule based on the Mises yield criterion, the representative stress—strain curves of a pre-strained specimen run parallel to that of an annealed material.

Sign in / Sign up

Export Citation Format

Share Document