Cyclic Stress-Strain and Constitutive Behaviors of SAC-Bi-Ni-Sb Solder Alloys During Fatigue Testing

2020 ◽  
Author(s):  
Mohd Aminul Hoque ◽  
Mohammad Ashraful Haq ◽  
Md Mahmudur Chowdhury ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Fatigue Testing ◽  
Cyclic Stress ◽  
Solder Alloys ◽  
Stress Strain

Critical Entropy Threshold: An Irreversible Thermodynamic Theory of Fatigue

2012 ◽  
Author(s):  
P. W. Whaley
Keyword(s):  
Fatigue Damage ◽  
Fatigue Testing ◽  
Tensile Tests ◽  
Cyclic Stress ◽  
Irreversible Thermodynamic ◽  
Fatigue Properties ◽  
Microplastic Deformation ◽  
Polycrystalline Materials ◽  
Model Parameters ◽  
Stress Strain

A theoretical model for material fatigue is described using irreversible thermodynamics to quantify fatigue damage by the generation of microplastic entropy. The microplastic entropy generated quantifies the microplastic deformation, commonly accepted as the mechanism of fatigue damage in polycrystalline materials. A stochastic model for microplastic deformation is utilized to calculate the expected values of tensile stress–strain, cyclic stress–strain, microplastic strain energy density and the microplastic entropy generated. When the cumulative microplastic entropy generated in cyclic loading exceeds the critical microplastic entropy threshold calculated from tensile tests, failure occurs. Calculated fatigue life with 99% tolerance limits (99% confidence) compares favorably to data for 6061-T6 aluminum rod and sheet specimens. Model parameters are determined from tensile tests and simple cyclic tests, decreasing the high cost of fatigue testing for parameter identification. This new theory has the potential to significantly decrease the cost of characterizing the fatigue properties of new materials.

Cyclic stress-strain response of porous aluminum

1990 ◽  
Vol 6 (2) ◽  
pp. 207-230 ◽  
Author(s):  
Han C. Wu ◽  
Paul T. Wang ◽  
W.F. Pan ◽  
Z.Y. Xu
Keyword(s):  
Cyclic Stress ◽  
Strain Response ◽  
Stress Strain ◽  
Porous Aluminum
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