Mechanical Behaviour of Stainless Steels under Dynamic Loading: An Investigation with Thermal Methods
AbstractStainless steels are the most exploited materials due to their high mechanical strength and versatility in producing different alloys. Although there is great interest in these materials, mechanical characterisation, in particular fatigue characterisation, requires the application of several standardised procedures involving expensive and time-consuming experimental campaigns. As a matter of fact, the use of Standard Test Methods does not rely on a physical approach, since they are based on a statistical evaluation of the fatigue limit with a fixed probabilistic confidence. In this regard, Infra-Red thermography, the well-known, non-destructive technique, allows for the development of an approach based on evaluation of dissipative sources. In this work, an approach based on a simple analysis of a single thermographic sequence has been presented, which is capable of providing two indices of the damage processes occurring in material: the phase shift of thermoelastic signal φ and the amplitude of thermal signal at twice the loading frequency, S2. These thermal indices can provide synergetic information about the mechanical (fatigue and fracture) behaviour of austenitic AISI 316L and martensitic X4 Cr Ni Mo 16-5-1; since they are related to different thermal effects that produce damage phenomena. In particular, the use of φ and S2 allows for estimation of the fatigue limit of stainless steels at loading ratio R = 0.5 in agreement with the applied Standard methods. Within Fracture Mechanics tests, both indices demonstrate the capacity to localize the plastic zone and determine the position of the crack tip. Finally, it will be shown that the value of the thermoelastic phase signal can be correlated with the mechanical behaviour of the specific material (austenitic or martensitic). View Full-Text
Share & Cite This Article
De Finis, R.; Palumbo, D.; Galietti, U. Mechanical Behaviour of Stainless Steels under Dynamic Loading: An Investigation with Thermal Methods. J. Imaging 2016, 2, 32.
De Finis R, Palumbo D, Galietti U. Mechanical Behaviour of Stainless Steels under Dynamic Loading: An Investigation with Thermal Methods. Journal of Imaging. 2016; 2(4):32.Chicago/Turabian Style
De Finis, Rosa; Palumbo, Davide; Galietti, Umberto. 2016. "Mechanical Behaviour of Stainless Steels under Dynamic Loading: An Investigation with Thermal Methods." J. Imaging 2, no. 4: 32.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.