Experimental Methodology for Thermo-Mechanical Stress Analysis

The experimental analysis of stresses in thermo-mechanical problems is fundamental for the design and evaluation of the mechanical behavior of structures, frames and various machine elements that operate under mechanical and thermal loads. It is also essential for complementing and validating analytical and numerical studies. This paper proposes an experimental methodology that allows the determination of plane states of stress—mechanical, thermal, and thermo-mechanical—based on the experimental measurement of thermo-mechanical deformation states at a surface point. Based on the theory of linear mechanical elasticity and applying the principle of superposition, plane thermo-mechanical constitutive models are developed, and methods are proposed that allow the thermal and mechanical variables in the models to be experimentally decoupled. The methodology was validated by thermal, mechanical and thermo-mechanical tests carried out on test specimens made of three materials: steel, aluminum and brass. The results show effectiveness in decoupling and solving the analytical models corresponding to the plane, mechanical, thermal, and thermo-mechanical states of stress. The maximum deviations obtained between the stresses provided by the formulated models and the experimental results were a maximum of 4% in most cases.