Thermal stress distributions and optimization on stress reductions with or/and without linearly graded interlayers

Features of thermal stress modifications by linearly graded interlayers (LGIs) are far beyond straightforward. This work adopts an analytical solution for thermal stress distributions in multilayer systems to carefully study two fundamental problems: thermal stress fields in a bilayer structure and detailed features of stress modifications due to an extra LGI. Results show that LGIs modify thermal stresses on contact and free surfaces in various ways. Such variations make the characteristics of stress reductions by using LGIs complicated. Five categories of stress variation patterns are classified, each of which provides a criteria of choosing an optimized interlayer thickness to reduce thermal stresses. The results serve as guidelines for structure designs and optimizations for thermal stress reductions.