M. Kikuchi et alii, Frattura ed Integrità Strutturale, 34 (2015) 318-325; DOI: 10.3221/IGF-ESIS.34.34 318 Focussed on Crack Paths Crack growth simulation in heterogeneous material by S-FEM and comparison with experiments Masanori Kikuchi Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan Yoshitaka Wada 3-4-1, Kowakae, Higashi-Oosaka, Oosaka, 577-0818, Japan Yulong Li Northwestern Polytechnical University, 127 Youyi Xilu, Xian 710072 Shaanxi, P.R.China A BSTRACT . Fully automatic fatigue crack growth simulation system is developed using S-version FEM (S- FEM). This system is extended to fracture in heterogeneous material. In the heterogeneous material, crack tip stress field becomes mixed mode condition, and crack growth path is affected by inhomogeneous materials and mixed mode conditions. Stress Intensity Factors (SIF) in mixed mode condition are evaluated using Virtual Crack Closure Method (VCCM). Criteria for crack growth amount and crack growth path are used based on these SIFs, and growing crack configurations are obtained. Three crack growth problems are simulated. One is crack growth in bi-materila made of CFRP plate and Aluminum alloy. Initial crack is located in CFRP plate, and grows toward Aluminum alloy. Crack growing direction changes and results are compared with experimental one. Second problem is crack growth in bi- material made of PMMA and Aluminum alloy. Initial crack is located in PMMA plate and parallel to phase boundary. By cahnging loading conditions, several cases are simulated and compared with experimental ones. In the experiment, crack grows into pahse boundary and grow along it. This case is simulated precisely, and the effect of pahse boundary is discussed. Last case is Stress Corrosion Cracking (SCC) at Hot-Leg Safe-End of Pressurized Water Rreactor. This location is made of many kinds of steels by welding. In some steel, SCC does not occur and in other steel, SCC is accelerated. As a result, small surface crack grows in complicated manner. K EYWORDS . Heterogeneous Material; S-FEM; Fatigue; SCC; VCCM. I NTRODUCTION atigue crack growth is important problem for the integrity of structures. To avoid catastrophic accident, predictions of crack growth path and fatigue life are key technologies. As fatigue crack growth occurs in complicated structures, these predictions have met serious difficulties. FEM is usually used for these predictions, F