Numerical analysis of temperature influence on deformation and effort of bimetallic element

Bimetallic elements consist of at least two, connected together, material layers. The materials have different coefficients of thermal expansion. An active layer of bimetallic elements has a greater thermal expansion coefficient, whereas a passive layer has a lower one. Therefore, deformation of bimetallic elements occurs due to a change in temperature. The simplest case of bimetallic elements is a strip, which bends in the shape of an arc. As a consequence of elements deformation, stresses appear in them. An important problem is optimization of each layer of the element to achieve certain characteristics of the system. The elements should work in an elastic domain in the entire operating range. The aim of the paper is to present both numerical and analytical results for three different bimetallic elements. The following pairs of materials are considered: invar – incoloy, steel – brass and aluminium – molybdenum subjected to uniform heating. An influence of temperature and active layer dimensions of the sample on deformation and stresses of each layer was developed. It was found that the stress value is close to zero, on the boundary of each layer, for characteristic deflections of the considered bimetallic elements. The results of numerical analyses were compared with a theoretical solution presented by Timoshenko. Numerical analyses were performed using the Finite Element Method implemented in the commercial software LS-Dyna.