ELASTIC-PLASTIC INVESTIGATION ON EFFECTIVENESS OF TWO DIMENSIONAL FUNCTIONALLY GRADED MATERIALS IN REDUCTION OF THERMAL STRESSES

Abstract

The two-dimensional functionally graded materials, (2D-FGMs) have been introduced in order to reduce the thermal stresses in machine elements that are subjected to severe thermal loading. No work was found that investigated the elastic-plastic stress analysis for 2D-FGMs. In the current work, a 3D finite element model of 2D-FGM plates made of ZrO2, 6061-T6 and Ti-6Al-4V with temperature dependent material properties has been proposed to perform such analysis. An elastic plastic stress-strain relation based on the rule of mixture of the 2D-FGM has been introduced. Also, a 3D finite element model of conventional FGM plates, of ZrO2/Ti-6Al-4V and ZrO2/6061-T6, with temperature dependent material properties has been proposed for the investigation of these plates too. Then, elastic-plastic stress analysis of the considered four plates (two conventional FGMs and two 2D-FGMs) under the same thermal loading was carried out. It was found that heat conductivity of the metallic constituents of FGM has great effect on the temperature distributions. Minimum temperatures variation and minimum stresses can be obtained using ZrO2/6061-T6/Ti-6Al-4V 2D-FGM. Also, the results indicate that only ZrO2/6061-T6/Ti-6Al-4V 2D-FGM can stand with the adopted severe thermal loading without cracking or fracture.