SEDL / STP / STP1220-EB / STP14625S

Interpretation of Warm Prestress-Induced Fracture Toughness Based on Crack-Tip Constraint

Shum, DKM
Development Staff, Oak Ridge National Laboratory, Oak Ridge, TN

Pages: 20    Published: Jan 1995

Download this paper for $25 PDF (320K)          View License Agreement
Abstract

This study explores the possibility of using J-Q-related crack-tip constraint concepts to provide a basis for both the interpretation of warm prestress (WPS)-induced fracture toughness and its transferability to structural applications. A finite-element boundary-layer formulation based on small-scale yielding (SSY), remote mode I K-dominant assumptions is adopted. Effects of WPS-induced crack-tip constraint are quantified in terms of deviation in either the opening-mode or the mean stress component of the WPS crack-tip fields relative to the reference K-dominant SSY state associated with monotonic-loading conditions. Over the range of WPS load-paths considered the WPS-induced crack-tip constraint closely resembles a spatially varying hydrostatic stress field. Interpretation and transferability of WPS fracture toughness under SSY conditions are specified in terms of the unload and reload ratio.