scholarly journals A Thermoelastic Stress Analysis General Model: Study of the Influence of Biaxial Residual Stress on Aluminium and Titanium

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 671 ◽  
Author(s):  
Francesca Di Carolo ◽  
Rosa De Finis ◽  
Davide Palumbo ◽  
Umberto Galietti
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Analysis ◽  
Thermoelastic Stress ◽  
Order Theory ◽  
Thermoelastic Stress Analysis ◽  
Thermoelastic Effect ◽  
Isotropic Materials ◽  
Model Study ◽  
Thermoelastic Equation

All the studies on the thermoelastic behaviour of materials, including the revised higher order theory on the thermoelastic effect, are based on several assumptions that limit the application of such theory to the cases of isotropic materials in the presence of uniaxial residual stresses and undergoing uniaxial applied loads. These assumptions lead to some discrepancies in the description of the real thermoelastic behaviour of materials in the presence of residual stresses. In this work, by rewriting the thermoelastic equation in a different way, it was possible to study the behaviour of homogeneous and non-isotropic materials undergoing any loading conditions and residual stresses. Firstly, the error made by the calibration procedures of thermoelastic stress analysis (TSA) data in the presence of residual stresses has been investigated. Then, a statistical analysis was carried out to determine the minimum value of residual stress which would lead to significant and measurable variations in the thermoelastic signal. The simulations involved two non-ferrous metals: AA6082 and Ti6Al4V, which exhibit a specific thermoelastic behaviour.

scholarly journals The interaction of fatigue cracks with a residual stress field using thermoelastic stress analysis and synchrotron X-ray diffraction experiments

2017 ◽  
Vol 4 (11) ◽  
pp. 171100 ◽  
Author(s):  
Khurram Amjad ◽  
David Asquith ◽  
Eann A. Patterson ◽  
Christopher M. Sebastian ◽  
Wei-Chung Wang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Crack Tip ◽  
Thermoelastic Stress ◽  
Thermoelastic Stress Analysis ◽  
X Ray Diffraction ◽  
Cold Expansion ◽  
X Ray ◽  
Stress Zone ◽  
Plastic Zones

This article presents an experimental study on the fatigue behaviour of cracks emanating from cold-expanded holes utilizing thermoelastic stress analysis (TSA) and synchrotron X-ray diffraction (SXRD) techniques with the aim of resolving the long-standing ambiguity in the literature regarding potential relaxation, or modification, of beneficial compressive residual stresses as a result of fatigue crack propagation. The crack growth rates are found to be substantially lower as the crack tip moved through the residual stress zone induced by cold expansion. The TSA results demonstrated that the crack tip plastic zones were reduced in size by the presence of the residual compressive stresses induced by cold expansion. The crack tip plastic zones were found to be insignificant in size in comparison to the residual stress zone resulting from cold expansion, which implied that they were unlikely to have had a notable impact on the surrounding residual stresses induced by cold expansion. The residual stress distributions measured along the direction of crack growth, using SXRD, showed no signs of any significant stress relaxation or redistribution, which validates the conclusions drawn from the TSA data. Fractographic analysis qualitatively confirmed the influence on crack initiation of the residual stresses induced by the cold expansion. It was found that the application of single compressive overload caused a relaxation, or reduction in the residual stresses, which has wider implications for improving the fatigue life.

A review of the general theory of thermoelastic stress analysis

2003 ◽  
Vol 38 (5) ◽  
pp. 405-417 ◽  
Author(s):  
G Pitarresi ◽  
E. A Patterson
Keyword(s):  
Stress Field ◽  
General Theory ◽  
Stress Analysis ◽  
Experimental Technique ◽  
Surface Stress ◽  
Thermoelastic Stress ◽  
Thermodynamic Theory ◽  
Thermoelastic Stress Analysis ◽  
Thermoelastic Effect ◽  
Insight Into

Thermoelastic stress analysis (TSA) is now a well-known experimental technique providing information on the surface stress field in structures. Many studies have assessed the potential of the technique for a number of applications and some useful and detailed reviews of these investigations are available, focusing mainly on the experimental aspects related to the measurement of the thermoelastic signal. In this work, instead, a complete and detailed insight into the origins of the various forms of the equations describing the thermoelastic effect is given with reference to the concepts of the thermodynamic theory of a continuum. A discussion on the theory leading to the thermoelastic effect law is intended to give a useful overview of the applications and real limitations of TSA.

The Potential for Assessing Residual Stress Using Thermoelastic Stress Analysis: A Study of Cold Expanded Holes

2012 ◽  
Vol 53 (2) ◽  
pp. 299-317 ◽  
Author(s):  
A. F. Robinson ◽  
J. M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete
Keyword(s):  
Residual Stress ◽  
Stress Analysis ◽  
Thermoelastic Stress ◽  
Thermoelastic Stress Analysis
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