Abstract
The goals of this research were to: (1) develop a model to represent the displacement field surrounding two interacting, parallel edge cracks; and (2) use this model to investigate the influence of crack separation and relative crack length on the interaction effects of the two cracks. Constitutive equations and strain-displacement relations were applied in conjunction with the combined Westergaard-Schwarz approach to obtain both u and v displacement field models of the multiple crack system. A local collocation analysis procedure was used, along with geometric moir6 experiments and finite element models, to both verify the validity of the model and investigate the interaction effects of the two cracks. Results were obtained for cases in which the length of one crack was kept fixed while the length of the second crack and the distance between the two cracks were varied. Experimental results were verified by comparing reconstructed and experimental moir6 fringe patterns while numerical results were verified by comparing J-integrals predicted through finite element analyses to those calculated through the analysis procedure. Comparison between experimental and numerical results demonstrated the applicability of the displacement field model to the geometry of interest. In addition, an examination of the results indicated that the relative crack length of the two cracks has a pronounced effect on opening mode stress intensity factors while the degree of crack separation has little or no effect for the crack separations studied. Although the interaction between the two cracks does introduce shear mode loading at the crack-tips, no significant effects were observed due to changes in either the relative crack length or crack separation.
Keener, Todd Whitney (1996). The displacement field characterization of two interacting parallel edge cracks in a finite body. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -K44.