报告题目： CMC Design Chain from Testing to Modeling – Characterization and Simulation of Mechanical Behavior of Ceramic Matrix Composites
Because of their favorable mechanical properties at high temperature and comparatively low density, Ceramic Matrix Composites (CMCs) have received considerable attention for aerospace defense, energy and environmental applications in the recent years. Currently, extensive research is being done on CMCs for their applications in “hot-zone” structures, as a replacement for metal alloys. The global CMC market is growing at a rapid rate. Geographically, the market is dominated by the USA, with a majority share of approx. 60 percent followed by the rest of the world. The market was valued at around one billion US$ in 2013 and is expected to grow at a Compound Annual Growth Rate (CAGR) of about 10 percent until 2018. The Global CMC market is driven by many growth factors. Increased demand from the Aviation industry is one of the major drivers in the Global CMC market. The Leap program initiated by GE Aviation is the major trend being witnessed by the Global CMC market. Increased economic development and growth of the Aviation sector in China has led to an increased demand for CMC in China. Despite the presence of several drivers, the Global CMC market is facing some challenges. The dearth of global demand is hindering the growth of this market. As most of the demand is being generated from developed nations, especially the US and west European, manufacturers are finding it difficult to expand geographically. In addition, the premium pricing of CMC-based products is a major challenge for vendors in the Global CMC market.
The application of CMCs strongly depends on the precise prediction of the failure behavior under real loading conditions. Therefore a comprehensive modeling approach is necessary which describes experimental testing results dependent on microstructure and fiber orientation as well as local defects like delamination or voids. The deterministic simulation presentedhere is based on a design chain consisting of non-destructive investigation of microstructure, inverse laminate theory for definition of laminate properties, finite element modeling for calculation of critical stresses and strains, definition of failure criteria, and resulting failure prediction considering effects of defects. Experimental data from all-oxide composite WHIPOX as well as from C/C-SiC processed via liquid silicon infiltration are used in order to proof the design chain. It is shown that in-plane strength and stiffness of WHIPOX can be predicted precisely considering any fiber orientation. The impact of interlaminar defects on failure prediction is shown on C/C-SiC composites. Here defects are implemented in the finite element model considering microstructural information from computer tomography and ultrasonic inspection. With use of fracture mechanical data damage evolution and valid failure prediction is possible and design and optimized engineering of CMC components is achievable.