We present models using a dislocation density to characterize a crack to investigate the behavior of a straight crack approaching the interface of a bimaterial system. Three cases of the crack approaching the interface of a bimaterial system are considered: a semi-infinite crack under concentrated loading, a finite crack under concentrated loading, and a finite crack under uniform pressure. The formulations of the model for investigating these cases lead to a system of singular integral equations. A collocation method is used to solve this system of singular integral equations. The effects of the orientation of the crack, the distance between the crack and the interface, and the material properties of the constituents of the systems, $\alpha$,$\beta$, are investigated. In each case the energy release rate, the stress intensity factors, and the probable angle of subsequent crack propagation from the pre-existing crack tip nearest the interface are computed. We find that for $\alpha$ $>$ 0 the crack in the lower material tends to curve away from the interface. Increasing the values of $\alpha$ or $\beta$ gives a greater curvature of the crack path. For $\alpha$ $<$ 0 the crack in the lower material tends to curve toward the interface and decreasing the values of $\alpha$ or $\beta$ gives a greater curvature of the crack path.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-8094 |
| Date | 01 January 1991 |
| Creators | Chen, Borliang |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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