Kamel, S.; Wimpory, R.C.; Hofmann, M.: The Effects of Constraint and Compressive or Tensile Residual Stresses on Brittle Fracture. In: Proceedings of the ASME Pressure Vessels and Piping Conference, July 26-30, 2009, Prague, Czech Republic. Vol. 5New York: American Society of Mechanical Engineers, 2010. - ISBN 978-0-7918-4368-0, p. 305-313
10.1115/PVP2009-77191
Abstract:
Residual stress is a key feature in components containing defects which can affect the crack driving force and alter the crack tip constraint to give a modified fracture toughness. In this paper experimental and numerical investigations are performed on ‘C’ shape fracture mechanics specimens, extracted from a high strength low alloy tubing steel, to examine the effects of constraint and tensile or compressive residual stress on brittle fracture. The residual stress is introduced into the specimens by a tensile or compressive mechanical pre-load to produce, respectively, a compressive or tensile residual stress in the region where the crack is introduced. Neutron diffraction measurements are performed on the pre-loaded specimens prior to introduction of a crack, and compared with predictions of the residual stress from finite-element analysis, using tensile properties derived at room temperature. Fracture toughness tests are carried out on the as received (non-preloaded) and pre-loaded specimens and the effect of residual stress on crack driving force and constraint is evaluated using the two-parameter J-Q approach.