Thermal Stress in Functionally Graded Plates with a Gradation of the Coefficient of Thermal Expansion Only

Baytak T. , Bulut O.

EXPERIMENTAL MECHANICS, 2022 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Doi Number: 10.1007/s11340-021-00818-2
  • Keywords: Functionally graded plates, Laminated composites, Photoelasticity, Stress concentration, Finite element analysis, Thermal stress, THERMOELASTIC ANALYSIS, RESIDUAL-STRESSES, FINITE-ELEMENT, FGM PLATES, FRACTURE


Background Experimental thermal stress analyzes of functionally graded materials should be performed accurately to validate existing numerical and analytical analyzes. The variation of stress concentration at the tip of a surface cavity should be investigated for long-term structural design. Objective In this study, an experimental and numerical model is developed to understand the thermal stress distribution in a functionally graded plate where only the coefficient of thermal expansion is graded. Methods Three-dimensional photoelasticity was used for experimental work with mechanical modelling of thermal expansion. An analytical solution for the thermal stress in a free plate was derived to validate the experimental and numerical analysis using finite element software. Results The stress concentration at the tip of the cavity changes with variation in tip radius and tip-to-interface distance, as shown experimentally. The stress at the tip of the cavity decreased when a mid-layer was added to a two-layered composite plate. An analysis of a particular substrate coated with a material whose coefficient of thermal expansion is graded with respect to two different functions shows that the optimum gradation should lie between the parabolic and linear functions. Conclusions The developed experimental and numerical models are very practical for the objective of thermal stress analysis in functionally graded plates. The stress concentration is reduced by coating the plate with a functionally graded material.