Time-Dependent Cyclic Deformation and Failure Behavior and Its Damage Coupled Simulation for Solder Alloy 63Sn-37Pb

2005 ◽  
Vol 297-300 ◽  
pp. 881-886 ◽  
Author(s):  
Xianjie Yang ◽  
Qing Gao
Keyword(s):  
Solder Alloy ◽  
Failure Criterion ◽  
Cyclic Deformation ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Time Dependent ◽  
Failure Behavior ◽  
Deformation And Failure ◽  
Viscoplastic Model ◽  
Dependent Behavior

The tests of 63Sn-37Pb under cyclic strain and stress were conducted to investigate the material’s time-dependent behavior. A damage-coupled viscoplastic model and its failure criterion are proposed. The prediction of the proposed viscoplastic model implies that the model can describe the cyclic strain and cyclic stress ratcheting behavior, and the fatigue lives very well.

Creep and Dilatancy Behavior of Rock Salt around Underground Caverns

2012 ◽  
Vol 629 ◽  
pp. 418-422
Author(s):  
S. Nazary Moghadam ◽  
H. Mirzabozorg ◽  
A. Noorzad ◽  
K. Nazokkar
Keyword(s):  
Finite Element ◽  
Rock Salt ◽  
Time Dependent ◽  
Finite Element Analyses ◽  
Volume Changes ◽  
Viscoplastic Model ◽  
Dependent Behavior ◽  
Underground Caverns ◽  
Finite Element Procedure ◽  
Stress And Deformation

In the present paper, the time-dependent behavior of a salt cavern was analyzed using finite element method. A viscoplastic model considering inelastic volume changes was utilized to describe the time-dependent mechanical behavior of rock salt. The model was then implemented in a finite element procedure to analyze the stress and deformation of rock salt around an underground cavern using an axisymmetric representation. Finally, finite element analyses results were compared with those obtained by a viscoplastic model neglecting inelastic volume changes.

Constitutive Modeling on Time-Dependent Deformation Behavior of 96.5Sn-3.5Ag Solder Alloy Under Cyclic Multiaxial Straining

2006 ◽  
Vol 129 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Xianjie Yang ◽  
Yan Luo ◽  
Qing Gao
Keyword(s):  
Solder Alloy ◽  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Back Stress ◽  
Time Dependent ◽  
Model Parameters ◽  
Stress Evolution ◽  
Deformation Properties ◽  
Strain Paths ◽  
Cyclic Straining

Based on the time dependent multiaxial deformation behavior of 96.5Sn-3.5Ag solder alloy, a constitutive model is proposed which considers the nonproportional multiaxial cyclic deformation properties. In the back stress evolution equations of this model, the nonproportionality which affects the back stress evolution rate is introduced. The approach for the determination of model parameters is proposed. The model is used to describe the time-dependent cyclic deformation behavior of 96.5Sn-3.5Ag solder alloy under cross, rectangular, rhombic, and double-triangular tensile–torsion multiaxial strain paths at different strain rates with different dwell time. The comparison between the predicted and experimental results demonstrates that the model can satisfactorily describe the time-dependent multiaxial cyclic deformation behavior under complicated nonproportional cyclic straining.

scholarly journals Correlation of Structural Ceramic Time Dependent Failure Data

1986 ◽  
Author(s):  
Lewis R. Swank
Keyword(s):  
Stress Rupture ◽  
Time Dependent ◽  
Failure Behavior ◽  
Flexural Stress ◽  
Failure Data ◽  
Dependent Behavior ◽  
Structural Applications ◽  
Rupture Data ◽  
Dependent Failure ◽  
Fast Fracture

Today there is a rapidly growing interest in the use of ceramics for structural applications. In applying structural ceramics it is necessary to estimate the time dependent failure behavior of the material. An analytical method is required to utilize flexural fast fracture and stress rupture data to predict the time dependent behavior of complex structures. This paper proposes an empirical equation to correlate the data. The proposed equation is applied to flexural and spin disk data. The flexural data correlate reasonably well. The spin disk data correlate well if the assumption is made that the stress in the flexural stress rupture specimens of the data base are those of steady state creep.

scholarly journals Generalized Relaxation Behavior of Rock Under Various Loading Conditions Using a Constant Linear Combination of Stress and Strain

2021 ◽  
Vol 9 ◽  
Author(s):  
Hailong Zhang ◽  
Yang Tang ◽  
Seisuke Okubo ◽  
Shoujian Peng ◽  
Cancan Chen
Keyword(s):  
Linear Combination ◽  
Control Method ◽  
Relaxation Behavior ◽  
Time Dependent ◽  
Feedback Signal ◽  
Failure Behavior ◽  
Stress And Strain ◽  
Loading Conditions ◽  
Underground Structures ◽  
Dependent Behavior

Time-dependent behavior has been demonstrated to be an essential factor in determining the long-term stability of underground structures. Creep and relaxation experiments are commonly used to investigate time-dependent behavior by subjecting rock to constant stress and strain. However, both stress and strain of in-situ rock masses are likely to change with time, a phenomenon known as generalized relaxation that has not been thoroughly investigated. In this study, a newly proposed control method with a constant linear combination of stress and strain as a feedback signal is used in compression and tension tests to investigate generalized relaxation behaviors of rocks. The results showed that the stress and strain of generalized relaxation are dependent on values of α, which represented generalized relaxation direction. The isochronous curves are enclosed within stress–strain curves of different loading conditions. The variation of stress (∆σ) and strain (∆ε) increases with increasing stress level and decreases with increasing confining pressure. Also, ∆σ and ∆ε in region II are smaller than in regions I and III. Furthermore, by performing brittle rock tests, complete generalized relaxation curves are obtained; three stages are observed, which are similar to conventional creep and relaxation behavior. Finally, the time and generalized relaxation failure behavior of Class I and Class II rock are discussed. The study is a valuable resource for gaining a comprehensive understanding of the time-dependent behavior of rocks and improving the stability and safety of underground structures.

Experimental Study on Uniaxial Time-Dependent Cyclic Deformation of POM/PTFE Blends

2011 ◽  
Vol 306-307 ◽  
pp. 1653-1657
Author(s):  
Zhi Wu Zhu ◽  
Xu Liu ◽  
Guo Zheng Kang ◽  
Li Xun Cai
Keyword(s):  
Cyclic Deformation ◽  
Volume Fraction ◽  
Stress Amplitude ◽  
Hold Time ◽  
Cyclic Strain ◽  
Peak Stress ◽  
Stress Rate ◽  
Time Dependent ◽  
Peak Strain ◽  
Ratcheting Strain

The uniaxial time-dependent cyclic deformation of POM/PTFE blends was studied experimentally under the stress-controlled and strain-controlled loading. The volume fraction of PTFE in the POM/PTFE blends was 20%. It was shown that the creep behavior of POM/PTFE blends is better than that of POM. In the cyclic strain-controlled experiments, the responded stress amplitude has a close relationship with the applied strain amplitude and strain rate. As a result of stress relaxation, the responded stress amplitude decreases as the hold time at peak strain increases. Ratcheting occurs in the blends subjected to asymmetric stress-controlled cyclic loading, and the ratcheting strain depends on the applied stress amplitude and stress rate. Hold time at peak stress and low stress rate lead to an increased ratcheting strain. The POM/PTFE blends will fail as the hold time at peak stress is longer than a critical value.

scholarly journals Viscoelastic-Viscoplastic Modelling of the Scratch Response of PMMA

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
G. Kermouche ◽  
N. Aleksy ◽  
J. M. Bergheau
Keyword(s):  
Experimental Study ◽  
A Priori ◽  
Constitutive Models ◽  
Young Modulus ◽  
Element Model ◽  
Time Dependent ◽  
Viscoplastic Model ◽  
Solid Polymers ◽  
Dependent Behavior ◽  
In Series

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.

A unified viscoplastic description of 63Sn-37Pb solder alloy under cyclic straining and stressing

2004 ◽  
Vol 218 (9) ◽  
pp. 909-920 ◽  
Author(s):  
X J Yang ◽  
C L Chow ◽  
K J Lau
Keyword(s):  
Constitutive Model ◽  
Solder Alloy ◽  
Deformation Behaviour ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Strain Rates ◽  
Viscoplastic Deformation ◽  
Stress Tests ◽  
Cyclic Tension ◽  
Cyclic Straining

A unified viscoplastic constitutive model for the fatigue life prediction of solder alloy 63Sn-37Pb is presented. The model incorporates the strain rate effect, the creep-plastic interaction and the dwell time effect under cyclic strain and stress loading. The applicability of this constitutive model is examined with cyclic strain tests with different strain rates, and cyclic stress tests under different stress waveforms in order to verify the progressive viscoplastic deformation of 63Sn-37Pb solder alloy. The investigation reveals that the material constants in the constitutive model can be determined by performing simple tests such as creep and cyclic tension-compression loading. The predictions using the constitutive model are found to agree well with the experimental results of the solder alloy under different loading. The agreement demonstrates that the model can satisfactorily describe the viscoplastic deformation behaviour under cyclic strain loading or stress loading.

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