BEHAVIOR OF STRESS SINGULARITIES NEAR THE FREE-EDGE OF CFC TZM BOND INTERFACE UNDER TRANSIENT HIGH HEAT-FLUX LOADING/

A duplex divertor component composed of dissimilar materials experienc es considerable thermal stresses under fusion operation conditions, du e to the mismatch of the thermal expansion. The stress states near the free edge of the bond interface are very critical because stress inte nsification occurs and sometimes stress singularities exist. The fract ure mechanical approach can be applied to characterize the behavior of these singular stress fields. A semi-analytical procedure is employed to describe the stress singularity in terms of the stress intensity f actor. Since some of critical fusion operating situations are coupled with the transient thermal flow, it is important to assess the design requirements for transient thermal loads. The applicability of the cur rent approach to a non-harmonic temperature field generated by a trans ient thermal load is discussed. The stress intensity factors are calcu lated for various transient high heat flux loads. The effect of the te mperature gradient at the interface on the stress singularity and on t he interfacial stress is investigated quantitatively. (C) 1998 Elsevie r Science S.A.