Bridging of Finite Element Models at sample and component level for UHTCMCs (Masterarbeit)

Abstract

The modeling of Ultra High Temperature Ceramic Matrix Composites (UHTCMC) is important to material science because of the relevance of this class of materials on an increasing number of aerospace applications. The ultimate interest of the engineers and scientists lies on the macrostructural properties of the final component. This level is studied using homogenized material properties, which are governed by the various and complex interactions on the microscale level. In this work a microstructural model based on Finite Element method simulations was mapped out. The focus of the work was the simulation of samples subjected to transverse tensile loading, having undergone temperature treatment. Given as the morphology of the microstructure dictates some of the most important features of the overall behavior, randomly generated microstructures were adopted to study the effects of voids and cracks in the matrix properties, thus using a computational methodology to describe the probabilistic strength distribution. Computational results were obtained on the effect of thermal load (cooling after the sintering process) on crack formation and ultimately on the stiffness of the composite. A baseline material with reference properties for future research was presented. A working model on the scale of a test coupon which employs the obtained results is presented, linking the macrostructural scale to the microstructural Representative Volume Element.