Original scientific paper

Application of Thermography in Analysis of Fatigue Strength of Materials and Structures

Lovre Krstulović Opara

Abstract

Thermography is becoming more and more relevant method in industry and as a research tool. It is an accepted method in many fields where non-destructive testing is carried out. In this paper focus was on evaluation of stress concentrations and fatigue of metal structures. Three thermographic methods: Thermoelastic stress analysis, Risitano method and acquisition of plastification zone and fracture propagation, are addressed and compared with results of classical cyclic testing of Al2024 alloy specimens. Specimens with three types of stress concentrator are used; 3 mm triangular notch, R3 mm circular notch, and a hole with 6 mm diameter. All thermographic methods showed high level of coincidence with classical fatigue tests. Thermoelastic stress analysis provides first stress invariant field for cyclic loaded sample, revealing stress concentrations near notches. Risitano method, from thermal dissipations at various levels of cyclic load, estimates dynamic strength of materials. Fast cooled middle-wave infrared cameras enable locating and tracing material plastification and fracture propagation. The outcomes of all evaluated methods are in accordance with each other.

Keywords

Thermoelastic stress analysis; Risitano method; plastification; fracture propagation; fatigue, cyclic loading

Hrčak ID:

148795

URI

https://hrcak.srce.hr/148795

Publication date:

1.6.2013.

Article data in other languages: croatian

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