A Comprehensive Study on Crack Tip Parameters of Modified Ring Specimen for Mixed-Mode Fracture Toughness Tests on Brittle Materials

作者：Pakzad R^*; Ayatollahi M R^*

来源：Geotechnical Testing Journal, 2016, 39(1): 144-156.

DOI：10.1520/GTJ20150071

• modified ring specimen
• mixed-mode loading
• finite element analyses
• fracture parameters

Modified ring (MR) specimen was suggested for investigating the mixed-mode (I/II) fracture behavior of brittle materials by rotating the crack orientation with respect to the loading direction. Crack tip fracture parameters (K-I, K-II, and T stress) of MR were calculated for different geometric dimensions. To verify the numerical modeling procedure, two sets of comparisons were drawn between the results of prior studies on MR Mode I fracture behavior and those of this study, showing good agreement between the results. Through some graphs, the effects of geometric parameters on Y-I, Y-II, and T* (dimensionless crack tip parameters) and also on beta(II) (pure Mode II crack angle) were studied. In addition, the biaxiality ratio (B), as an influential factor in the generalized maximum tangential stress (GMTS) criterion, was calculated for the whole range of mode mixity in the MR specimens. Next, fracture behavior of the specimen was discussed by means of the GMTS criterion in terms of the results obtained for the biaxiality ratio (B). At the end, as an appendix, the entire results obtained for Y-I, Y-II, T*, and beta(II) were presented.

• 出版日期2016-1