Constitutive Modeling for Uniaxial Time-Dependent Ratcheting of SS304 Stainless Steel

2007 ◽  
Vol 340-341 ◽  
pp. 817-822 ◽  
Author(s):  
Guo Zheng Kang ◽  
Qian Hua Kan ◽  
Juan Zhang ◽  
Yu Jie Liu

Based on the experimental results of uniaxial time-dependent ratcheting behavior of SS304 stainless steel at room temperature and 973K, three kinds of time-dependent constitutive models were employed to describe such time-dependent ratcheting by using the Ohno-Abdel-Karim kinematic hardening rule, i.e., a unified viscoplastic model, a creep-plasticity superposition model and a creep-viscoplasticity superposition model. The capabilities of such models to describe the time-dependent ratcheting were discussed by comparing with the corresponding experimental results. It is shown that the unified viscoplastic model cannot provide reasonable simulation to the time-dependent ratcheting, especially to those with certain peak/valley stress hold and at 973K; the proposed creep-plasticity superposition model is reasonable when the creep is a dominant factor of the deformation, however, it cannot provide a reasonable description when the creep is weak; the creep-viscoplastic superposition model is reasonable not only at room temperature but also at high temperature.

1983 ◽  
Vol 105 (4) ◽  
pp. 250-256 ◽  
Author(s):  
J. R. Ellis ◽  
D. N. Robinson ◽  
C. E. Pugh

This paper describes two biaxial experiments which investigated time and rate effects in the yield and deformation behavior of type 316 stainless steel at room temperature. The first experiment was aimed at determining the effect of probing rate on small-offset yield behavior. The primary aim of the second experiment was to investigate time-dependent flow after loading beyond initial yield. An additional aim was to investigate the effect of radial (3 σ12 = σ11) and nonradial preloads on the yield and hardening behavior. The first experiment showed that for the limited range investigated, 100 to 500 με/min, the probing rate had little effect on yield behavior. The small differences observed in the size and position of certain yield surfaces were shown to be related to the sequence in which the yield loci were determined. The second experiment showed that yield surfaces suffered considerable distortion from their initial near-circular form after both radial and nonradial preloads beyond initial yield. It also showed that the hardening behavior was predominantly kinematic for both types of preload. The strain-time data obtained after the preloads in this experiment showed characteristics typical of creep curves. A transient flow period was observed with high initial strain rates diminishing one or two orders of magnitude during the 0.5-h hold periods. This means that in detailed mechanical modeling of this material, careful attention should be given to time-dependent effects, even at room temperature.


Author(s):  
A. S. Zaki ◽  
H. Ghonem

Abstract This paper describes the cyclic accumulative plastic strain in a polycrystalline material when subjected to loading conditions promoting ratcheting behavior. For this purpose, a unified viscoplastic constitutive model based on non-linear kinematic hardening formulation is implemented. Identification of the model parameters was carried out using an experimental program that included monotonic, cyclic and relaxation testing. Simulation of the material response using the proposed model is compared with experimental results for the same loading. This comparison is used to evaluate the model validity.


2012 ◽  
Vol 151 ◽  
pp. 721-725
Author(s):  
R. Suresh Kumar ◽  
P. Chellapandi ◽  
C. Lakshmana Rao

Mechanical behavior of the austenitic stainless steel under monotonic and cyclic loading at room temperature has been mathematically predicted. Materials like SS 316 LN exhibit cyclic hardening behavior under cyclic loading. Based on the characteristics of yield surface, cyclic hardening can be classified into isotropic and kinematic hardening. Armstrong-Frederic model is used for predicting the kinematic hardening of this material. It is basically a five parameter, nonlinear kinematic hardening model. Cyclic tests for various ranges were carried out to derive the isotropic material parameter required for modeling. Kinematic hardening material parameter required for modeling were computed based on both monotonic tension and torsion tests. By using these parameters the developed program is able to model the mechanical behavior of austenitic stainless steel under monotonic and cyclic loading conditions at room temperature. Comparison of the predicted results with the experimental results shows that the kinematic hardening material parameters derived from the monotonic torsion tests were in good agreement than that of the monotonic tension tests. Also it is recommended to use more material parameter constitutive models to improve the accuracy of the mathematical predictions for the material behavior under cyclic loading.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
G. Kermouche ◽  
N. Aleksy ◽  
J. M. Bergheau

This paper aims at understanding how to model the time-dependent behavior of PMMA during a scratch loading at a constant speed and at middle strain levels. A brief experimental study is first presented, consisting of the analysis of microscratches carried out at various scratching velocities and normal loads. The loading conditions have been chosen in such a way that neither (visco)elasticity nor (visco)plasticity of the PMMA may be neglected a priori. The main analyzed parameter is the tip penetration depth measured during the steady state. Then, a finite element model is used to investigate the potential of classical elastic-viscoplastic constitutive models to reproduce these experimental results. It is mainly shown that these models lead to unsatisfying results. More specifically, it is pointed out here that the time-independent Young modulus used in such models is not suitable. To take into account this feature, a viscoelastic-viscoplastic model based on the connection in series of a viscoelastic part with a viscoplastic part is proposed. It is shown that it leads to more acceptable results, which points out the importance of viscoelasticity in the scratch behavior of solid polymers.


2021 ◽  
Vol 276 ◽  
pp. 122175
Author(s):  
Dafu Wang ◽  
Yunsheng Zhang ◽  
Jia Xiao ◽  
Tingjie Huang ◽  
Meng Wu ◽  
...  

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