A note on the use of the thermal response to deformation as a damage assessment tool

The choice of thermal analysis to evaluate the monoaxial fatigue strength on materials and mechanical components

“…Based on the results obtained in the dynamic field, the authors carried out static tensile tests on different materials and mechanical components and compared the results with those obtained from fatigue testing. As indicated by thermoelastic theory, and confirmed by tests previously performed on steel and composite specimens, 56–66 the thermal variations for tensile stress are negative and linearly decreasing with the applied load (Figure 8, phase 1). The gradient of the curve inverts the sign and the thermal variations become positive in the plastic phase, as previously demonstrated.…”

“…The gradient of the curve inverts the sign and the thermal variations become positive in the plastic phase, as previously demonstrated. 56–58 It is also possible to distinguish the variation in the slope of the thermal response in the elastic field (phase 2). The applied load, in fact, produces local plastic deformations, which are great enough to affect the thermal behavior.…”

Combined experimental methods to assess the fatigue limit

“…Many researchers have performed different methodologies to detect the fatigue parameters using thermography in rapid tests and, consequently many procedures were defined to assess the fatigue and fracture limit, applying single load or a sequence of incremental loading steps [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].These procedures allow assessing the fatigue life [5], the cumulative damage [14], and finally, the fatigue limit under the application of simple static loading also [20][21][22][23]. The latter method is based on the limit of the linear thermoelasticity as the starting of the fatigue process [24,25].…”