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#15685, Numerical Simulation of the Heat Dissipation During the Fatigue Test

Fatigue is an irreversible process which is accompanied by the heat dissipation which is significant when the transition from anelastic (irreversible but recoverable) to inelastic (irreversible and unrecoverable) strains happens. It has been accepted as a more appropriate damage indicator.
The evaluation of the heat dissipation needs to capture appropriate features from the surface of the specimen by using thermography techniques.
It should be noted that the energy dissipation is highly sensitive to the inner material status and its estimation is crucially influenced by the environmental conditions. Any simplifications on either the heat equation or the temperature profile acquisition from the real condition of the fatigue test will certainly cause deviations not only from the exact phenomenon of the energy dissipation but also between each approach’s prediction. Therefore, experimentally estimation of the heat dissipation via thermography-based approached is almost associated with some errors. One way to detect the dissipation is building up a reliable numerical model that would help to simulate the thermal variations and draw some considerations on the quality of the measurements or the effectiveness of the analyzed thermal components.
This paper is mainly focused on the numerical modeling of the heat dissipation. It can provide valuable insights about the shape and location of the heat sources produced during the cyclic loading and the error associated with thermographic measurements, which are the main goals of this work. The thermal finite element simulation is performed by COMSOL Multiphysics software. The model has the capability to simulate a constant or a cyclic heat source which is a representative of the heat generated during the fatigue test. It is validated by both the experimental data and analytical data from one-dimensional heat equation solution.

Mohammad Zaeimi   Politecnico di Bari
Rosa De Finis   Politecnico di Bari
Davide Palumbo   Politecnico di Bari
Umberto Galietti   politecnico di Bari