A fractional viscoplastic model to predict the time-dependent displacement of deeply buried tunnels in swelling rock

2021 ◽  
Vol 129 ◽  
pp. 103901
Author(s):  
Geng-Yun Liu ◽  
You-Liang Chen ◽  
Xi Du ◽  
Rafig Azzam
Keyword(s):  
Time Dependent ◽  
Viscoplastic Model ◽  
Swelling Rock

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
Keyword(s):  
Stainless Steel ◽  
Room Temperature ◽  
Kinematic Hardening ◽  
Constitutive Models ◽  
Experimental Results ◽  
Time Dependent ◽  
Dominant Factor ◽  
Superposition Model ◽  
Viscoplastic Model ◽  
Reasonable Description

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.

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.

Observed and calculated pore pressures and deformations induced by an earth balance shield

1993 ◽  
Vol 30 (3) ◽  
pp. 476-490 ◽  
Author(s):  
X. Yi ◽  
R. Kerry Rowe ◽  
K.M. Lee
Keyword(s):  
Finite Element ◽  
Numerical Technique ◽  
Field Measurements ◽  
Time Dependent ◽  
Creep Tests ◽  
Viscoplastic Model ◽  
Pore Pressures ◽  
Triaxial Creep ◽  
Consolidation Analysis ◽  
Triaxial Creep Tests

The observed pore pressures and deformations induced by an earth balance shield used to construct the Furongjiang sewer tunnel in soft saturated ground in Shanghai, China, are briefly described. A numerical technique for predicting these pore pressures and deformations is outlined. This approach adopts a coupled viscoplastic-consolidation analysis to describe the time-dependent deformations and strain-hardening behaviour of the soil using parameters obtained from triaxial creep tests. A comparison is then made between numerical results and the results of field measurements, and it is shown that there is encouraging agreement between the calculated and observed response. Key words : tunnelling, finite element, settlements, viscoplastic model, consolidation, field measurement.

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.

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.

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