Determining fatigue limits with thermal analysis of static traction tests

• Published in: Fatigue & fracture of engineering materials & structures Vol. 36; no. 7; pp. 631 - 639
• Main Authors: Risitano, A., Risitano, G.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.07.2013; Blackwell; Wiley Subscription Services, Inc
• Subjects: Applied sciences; Exact sciences and technology; Fatigue; Fatigue failure; Fatigue life; Fatigue limit; IR images; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; mono-axial static test; Nonlinearity; RMR; Static electricity; Stress strain curves; Stress-strain relationships; Stresses; Structural steels; Tests; Thermal energy; Traction; Mechanical properties; Fatigue; IR images; Fatigue limit; mono-axial static test; RMR
• ISSN: 8756-758X; 1460-2695
• DOI: 10.1111/ffe.12030

ABSTRACT This work evaluates the limit stress of the thermo‐elastic phase of deformation by thermo‐analysing the surface of a specimen during a static traction test. By adding a temperature curve measured over a small area of the surface to the classical stress–strain curve, it is possible to evaluate a limit temperature T0 that is coincident with the beginning of the curve's nonlinear trend. The corresponding stress value is as estimation of the fatigue limit of the component under analysis. The authors derive an expression to evaluate temperature during a mono‐axial static traction test. As an example, temperature curves recorded during traction tests performed on two notched steel specimens are reported and compared with this proposed expression. The change to the linearity in the temperature curve during the static traction test is evident in these examples and the corresponding stress value is an estimation of the fatigue limit of the component under analysis.