Effects of interface and tensile properties in the dynamic fracture of layered structures

Finite element modeling of crack extension under impact was performed to st udy the suitability of layered composite structures in plasma-facing and pr imary wall structures for ITER and other fusion devices. The layers may con sist of dissimilar metal alloys, each of which performs a necessary design function for sputtering resistance, heat removal, and structural integrity. Several layered structures with varying material properties were modelled using finite element analysis. Compared to monolithic solid bars with the s ame mechanical properties, layered structures with frictional interfaces di ssipate more energy before a pre-crack normal to the interface can propagat e. For these layered structures, there is an optimum for the coefficient of friction that provides maximum resistance to crack extension. (C) 1999 Els evier Science B.V. All rights reserved.