An improved elasto-plastic constitutive model for the exquisite description of stress-strain hysteresis loops with cyclic hardening and softening effects

2020 ◽  
Vol 150 ◽  
pp. 103590 ◽  
Author(s):  
Li-Yan Xu ◽  
Jian-Sheng Fan ◽  
Yue Yang ◽  
Mu-Xuan Tao ◽  
Zhen-Yun Tang
Keyword(s):  
Constitutive Model ◽  
Hysteresis Loops ◽  
Cyclic Hardening ◽  
Stress Strain ◽  
Hardening And Softening

An Exponential Stress-Strain Law for Cyclic Plasticity

1976 ◽  
Vol 98 (4) ◽  
pp. 322-329 ◽  
Author(s):  
M. C. M. Liu ◽  
E. Krempl ◽  
D. C. Nairn
Keyword(s):  
Hysteresis Loops ◽  
Cyclic Hardening ◽  
Cyclic Plasticity ◽  
304 Stainless Steel ◽  
Strain Diagram ◽  
Stress Strain ◽  
Independent Case ◽  
Transcendental Functions ◽  
Product Forms ◽  
Type 304

A previously proposed nonlinear differential constitutive equation for creep-plasticity interaction under a uniaxial state of stress is specialized for the time independent case. The characteristics of the second derivative of the stress-strain diagram are matched by an exponential function. The integration yields higher transcendental functions. For the matching of the stress-strain diagram, four easily obtainable constants are necessary at each cycle which are fed into a newly developed FORTRAN computer program. A plotting routine yields stress-strain diagrams and hysteresis loops. The procedure gives good matches for stress-strain diagrams of Type 304 stainless steel. Specifically, stress-strain diagrams for various product forms and the initial cyclic hardening of this material are reproduced quite accurately without the usual decomposition into elastic and plastic strains.

Prediction of settled cyclic behaviour of metals using first cycle data and combined hardening laws for reversed plasticity

1994 ◽  
Vol 29 (2) ◽  
pp. 105-116
Author(s):  
V O A Oloyede ◽  
C E Turner
Keyword(s):  
Hysteresis Loops ◽  
Cyclic Hardening ◽  
Cyclic Stress ◽  
Yield Function ◽  
Stress Strain ◽  
Finite Element Program ◽  
Cyclic Behaviour ◽  
Element Program ◽  
Combined Hardening ◽  
Good Agreement

This paper presents a generalized concept of combined hardening which is examined by experimental and computational methods. A ‘kinematic displacement parameter’, β, relating the movement of the yield function surface to the Bauschinger effect, is defined in terms of its dependence on material properties and loading state. Experimental relations between β and the plastic strain, εp, are prsented for three metals. The monotonic stress-strain and β data are used in a finite element program to show that settled cyclic hysteresis loops are soon established. Settled cyclic stress-strain curves computed in this way are in good agreement with the experimental results for an aluminium alloy, a stainless steel that shows cyclic hardening, and a titanium alloy that shows little cyclic effect.

Effect of Temperature on the Cyclic Stress Components of Gamma - TiAl Based Alloy with Niobium Alloying

2011 ◽  
Vol 465 ◽  
pp. 447-450 ◽  
Author(s):  
Martin Petrenec ◽  
Petr Buček ◽  
Tomáš Kruml ◽  
Jaroslav Polák
Keyword(s):  
Hysteresis Loops ◽  
Lamellar Microstructure ◽  
Strain Curve ◽  
Cyclic Strain ◽  
Cyclic Hardening ◽  
Cyclic Stress ◽  
Effect Of Temperature ◽  
Stress Strain ◽  
Stress Components ◽  
Increasing Temperature

Cyclic strain controlled multiple step tests have been performed on cylindrical specimens of cast -TiAl based alloy with 2 at.% of Nb with nearly lamellar microstructure at 23 and 750 °C in laboratory atmosphere with the aim to study the effect of temperature on the internal and effective cyclic stress components. At these temperatures, the evolution of the effective and internal stress components and the effective elastic moduli were derived from the hysteresis loops analyzed according to the statistical theory of hysteresis loop. Cyclic hardening/softening curves and cyclic stress-strain curves were obtained at both temperatures. Cyclic stress–strain curves measured using short-cut procedure coincide with the basic cyclic stress-strain curve. They are shifted to lower stresses with increasing temperature. Cyclic stress-strain response at both temperatures was compared and discussed in relation to changes of internal and effective stress components and dislocation modes referred in literature concerning this class of the material.

Application of a Theory of Viscoplasticity to Uniaxial Cyclic Loading

1983 ◽  
Vol 105 (2) ◽  
pp. 106-112 ◽  
Author(s):  
M. A. Eisenberg ◽  
C.-F. Yen
Keyword(s):  
Cyclic Loading ◽  
Strain Amplitude ◽  
Cyclic Hardening ◽  
Stress Strain ◽  
Random Inputs ◽  
Rate Dependent ◽  
Nonlinear Stress ◽  
Realistic Description ◽  
Incremental Step ◽  
Hardening And Softening

The uniaxial specialization of a theory of cyclic viscoplasticity is described. The theory incorporates a realistic description of nonlinear stress-strain curves and of transient cyclic hardening and softening in both rate-dependent and rate-independent approximations. The applications to constant strain amplitude, incremental step tests, and random inputs are demonstrated.

scholarly journals A General Temperature-Dependent Stress–Strain Constitutive Model for Polymer-Bonded Composite Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1393
Author(s):  
Xiaochang Duan ◽  
Hongwei Yuan ◽  
Wei Tang ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Composite Materials ◽  
Constitutive Model ◽  
Model Parameters ◽  
Temperature Dependent ◽  
Stress Strain ◽  
Proposed Model ◽  
Single Temperature ◽  
Testing Data ◽  
Bonded Composite ◽  
Tension And Compression

This study develops a general temperature-dependent stress–strain constitutive model for polymer-bonded composite materials, allowing for the prediction of deformation behaviors under tension and compression in the testing temperature range. Laboratory testing of the material specimens in uniaxial tension and compression at multiple temperatures ranging from −40 ∘C to 75 ∘C is performed. The testing data reveal that the stress–strain response can be divided into two general regimes, namely, a short elastic part followed by the plastic part; therefore, the Ramberg–Osgood relationship is proposed to build the stress–strain constitutive model at a single temperature. By correlating the model parameters with the corresponding temperature using a response surface, a general temperature-dependent stress–strain constitutive model is established. The effectiveness and accuracy of the proposed model are validated using several independent sets of testing data and third-party data. The performance of the proposed model is compared with an existing reference model. The validation and comparison results show that the proposed model has a lower number of parameters and yields smaller relative errors. The proposed constitutive model is further implemented as a user material routine in a finite element package. A simple structural example using the developed user material is presented and its accuracy is verified.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

The Constitutive Model for High Temperature Flow Behavior of SiC/6168Al Composite

2015 ◽  
Vol 1089 ◽  
pp. 37-41
Author(s):  
Jiang Wang ◽  
Sheng Li Guo ◽  
Sheng Pu Liu ◽  
Cheng Liu ◽  
Qi Fei Zheng
Keyword(s):  
Constitutive Model ◽  
Hot Deformation ◽  
Flow Behavior ◽  
Type Equation ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Stress Strain ◽  
Hollomon Parameter ◽  
Proposed Model ◽  
Relationship Of

The hot deformation behavior of SiC/6168Al composite was studied by means of hot compression tests in the temperature range of 300-450 °C and strain rate range of 0.01-10 s-1. The constitutive model was developed to predict the stress-strain curves of this composite during hot deformation. This model was established by considering the effect of the strain on material constants calculated by using the Zenter-Hollomon parameter in the hyperbolic Arrhenius-type equation. It was found that the relationship of n, α, Q, lnA and ε could be expressed by a five-order polynomial. The stress-strain curves obtained by this model showed a good agreement with experimental results. The proposed model can accurately describe the hot flow behavior of SiC/6168Al composite, and can be used to numerically analyze the hot forming processes.

Generation of Cyclic Stress-Strain Curves for Sheet Metals

2000 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
High Strength ◽  
Cyclic Stress ◽  
Bending Moments ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Material Parameters

Abstract The main objective of this paper is to generate cyclic stress-strain curves for sheet metals so that the springback can be simulated accurately. Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.

A multiaxial stress-strain analysis for proportional cyclic loading

1993 ◽  
Vol 28 (2) ◽  
pp. 125-133 ◽  
Author(s):  
A Navarro ◽  
M W Brown ◽  
K J Miller
Keyword(s):  
Strain Analysis ◽  
Hysteresis Loops ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Strain Hardening Exponent ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Flow Equations ◽  
Deformation Response ◽  
Tubular Specimens

A simplified treatment is presented for the analysis of tubular specimens subject to in-phase tension-torsion loads in the elasto-plastic regime. Use is made of a hardening function readily obtainable from the uniaxial cyclic stress-strain curve and hysteresis loops. Expressions are given for incremental as well as deformation theories of plasticity. The reversals of loading are modelled by referring the flow equations to the point of reversal and calculating distances from the point of reversal using a yield critertion. The method has been used to predict the deformation response of in-phase tests on an En15R steel, and comparisons with experimental data are provided. The material exhibited a non-Masing type behaviour. A power law rule is developed for predicting multiaxial cyclic response from uniaxial data by incorporating a hysteretic strain hardening exponent.

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