Quantifications of crack constraint effects in an austenitic steel

• DOI: 10.1007/bf00033722
• Publication Date: 2004-11-03T11:13:39Z
• Authors: Huang Yuan; Guoyu Lin; Alfred Cornec
• Keywords: 0203 mechanical engineering; 02 engineering and technology

In this paper we studied the quantitative assessment of the constraint effects at the crack-tip fields in an austenitic stainless steel (X6CrNi1811). The J-Q annulus was verified in two-dimensional crack fields under both small-scale and general vielding conditions. Four different geometries with shallow through deep cracks were studied. It has been shown that the Q values versus the J-integral are strongly dependent on the stress-strain curve. J-T gives an accurate description of the crack-tip state only at low load. In three-dimensional crack analysis, the stress fields tend towards the plane stress solution in both thick and thin specimens. The specimen thickness thus plays a key role in characterisation of the three-dimensional crack-tip fields. The second terms in the three-dimensional stress fields depend on distance to the tip and to the free edge-surface of the specimen. It has been shown that the stress triaxiality at the crack tip is essentially a linear function of Q. In the CT specimens examined, Q locally characterises the stress triaxiality at the three-dimensional crack-tip front fields.