Constitutive modelling and its application to stress-relaxation age forming of AA6082 with elastic and plastic loadings

2021 ◽  
Vol 295 ◽  
pp. 117168
Author(s):  
Qi Rong ◽  
Zhusheng Shi ◽  
Yong Li ◽  
Jianguo Lin
Keyword(s):  
Stress Relaxation ◽  
Constitutive Modelling

scholarly journals Constitutive Modelling of Polylactic Acid at Large Deformation Using Multiaxial Strains

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2967
Author(s):  
John Sweeney ◽  
Paul Spencer ◽  
Glen Thompson ◽  
David Barker ◽  
Phil Coates
Keyword(s):  
Steady State ◽  
Stress Relaxation ◽  
Strain Hardening ◽  
Small Strain ◽  
Limited Range ◽  
Constitutive Modelling ◽  
True Stress ◽  
Final Strain ◽  
Transverse Stresses

Sheet specimens of a PLLA-based polymer have been extended at a temperature near to the glass transition in both uniaxial and planar tension, with stress relaxation observed for some time after reaching the final strain. Both axial and transverse stresses were recorded in the planar experiments. In all cases during loading, yielding at small strain was followed by a drop in true stress and then strain hardening. This was followed by stress relaxation at constant strain, during which stress dropped to reach an effectively constant level. Stresses were modelled as steady state and transient components. Steady-state components were identified with the long-term stress in stress relaxation and associated with an elastic component of the model. Transient stresses were modelled using Eyring mechanisms. The greater part of the stress during strain hardening was associated with dissipative Eyring processes. The model was successful in predicting stresses in both uniaxial and planar extension over a limited range of strain rate.

Constitutive modelling of compression and stress relaxation in pine pellets

2019 ◽  
Vol 130 ◽  
pp. 105370 ◽  
Author(s):  
Simon Klinge Nielsen ◽  
Hamid Rezaei ◽  
Matthias Mandø ◽  
Shahab Sokhansanj
Keyword(s):  
Stress Relaxation ◽  
Constitutive Modelling

Rate-dependent shear deformation of ductile acrylic adhesive and its constitutive modelling

2004 ◽  
Vol 218 (6) ◽  
pp. 623-629 ◽  
Author(s):  
M Takiguchi ◽  
S Izumi ◽  
F Yoshida
Keyword(s):  
Flow Stress ◽  
Stress Relaxation ◽  
Early Stage ◽  
Deformation Behaviour ◽  
Constitutive Modelling ◽  
Shear Tests ◽  
Adhesive Resin ◽  
Acrylic Adhesive ◽  
Rate Dependent ◽  
Lap Shear

Recently, new types of structural adhesive with high ductility, as well as high strength, have been developed and put on the market. Such high ductile adhesives usually have strong rate sensitivity in their flow stress. In order to investigate the rate-dependent deformation behaviour of an acrylic adhesive, tensile lap shear tests were performed at various crosshead speeds at room temperature. Stress relaxation tests were also performed. In the tensile lap shear tests, it was found that the shear flow stress of the adhesive resin increased remarkably with increasing shearing speed. In the stress relaxation tests, the stress decreased rapidly at the early stage, and it gradually approached an asymptotic stress value. In order to describe such rate-dependent deformation characteristics of adhesive resin, a viscoplastic constitutive model is presented in this paper. The shear stress-strain responses, as well as stress relaxation behaviour, predicted by the present model agree well with the corresponding experimental results.

scholarly journals Experimental studies and constitutive modelling of AA6082 in stress-relaxation age forming conditions

2017 ◽  
Vol 207 ◽  
pp. 293-298 ◽  
Author(s):  
Q. Rong ◽  
Z. Shi ◽  
X. Li ◽  
X. Sun ◽  
Y. Li ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Experimental Studies ◽  
Constitutive Modelling

Stress Relaxation and the Formation of Silicides in the Process of the Crystallization of NI-NB Films on SI

1991 ◽  
Vol 49 ◽  
pp. 898-899
Author(s):  
N. Rozhanski ◽  
V. Lifshitz
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Integrated Circuits ◽  
Direct Evidence ◽  
Alloy Film ◽  
Diffusion Barriers ◽  
Effective Barrier

Thin films of amorphous Ni-Nb alloys are of interest since they can be used as diffusion barriers for integrated circuits on Si. A native SiO2 layer is an effective barrier for Ni diffusion but it deformation during the crystallization of the alloy film lead to the appearence of diffusion fluxes through it and the following formation of silicides. This study concerns the direct evidence of the action of stresses in the process of the crystallization of Ni-Nb films on Si and the structure of forming NiSi2 islands.

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