scholarly journals Constitutive modelling of a T74 multi-step creep ageing behaviour of AA7050 and its application to stress relaxation ageing in age formed aluminium components

2017 ◽  
Vol 207 ◽  
pp. 281-286 ◽  
Author(s):  
Jing-Hua Zheng ◽  
Catrin M. Davies ◽  
Jianguo Lin ◽  
Ran Pan ◽  
Chen Li
Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2967
Author(s):  
John Sweeney ◽  
Paul Spencer ◽  
Glen Thompson ◽  
David Barker ◽  
Phil Coates

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.


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

Author(s):  
M Takiguchi ◽  
S Izumi ◽  
F Yoshida

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.


2017 ◽  
Vol 207 ◽  
pp. 293-298 ◽  
Author(s):  
Q. Rong ◽  
Z. Shi ◽  
X. Li ◽  
X. Sun ◽  
Y. Li ◽  
...  

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