Effects of the limited region of K-dominance in the mixed-mode delaminating beam test specimen
- Lawrence Berkeley National Lab., CA (United States); and others
The mixed-mode delaminating beam is a widely used test geometry designed to measure the fracture resistance of bimaterial interfaces under mixed-mode loading conditions. In the present work, linear-elastic finite-element analyses are employed to determine the complex stress intensity factor, K, for an interfacial crack in this sample; results are found to confirm those of previous studies. However, the numerical results further reveal that the region of K-dominance near the crack tip is very limited, extending merely {approximately} 1/100 to 1/1000 of the sample height, about an order of magnitude smaller than for other common fracture-mechanics test samples. Analyses performed for this specimen geometry modified to include a thin sandwiched interlayer also indicate a very limited region of K-dominance, extending {approximately}1/20 of the height of the sandwiched layer from the crack tip for very thin sandwiched layers. Examples of the use of this specimen in the evaluation of the fracture toughness of ceramic joints are cited from the literature and comparisons are made between the size of the K-dominant region and the extent of crack tip plasticity. Based on these comparisons, the predictive power of linear-elastic fracture mechanics for common bimaterial couples and specimen dimensions using this geometry is challenged.
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 539141
- Report Number(s):
- CONF-9604124--
- Country of Publication:
- United States
- Language:
- English
Similar Records
J-integral for a semi-elliptical surface crack at a bimaterial interface
Accuracy assessment of the singular-field-based mode-mix decomposition procedure for the prediction of delamination