Mode I fracture initiation in limestone by strain energy density criterion

Calculation of the crack tip parameters in the holed‐cracked flattened Brazilian disk (HCFBD) specimens under wide range of mixed mode I/II loading

“…showed that the fracture path in the SCB samples under mixed mode loading can be predicted in good agreement with the experimental results when the non‐singular term T is taken into account. Ayatollahi and Sedighiani demonstrated also that the classical SED criterion can provide good estimates for the mode I fracture behavior of Guiting limestone obtained from the SCB and CCCD specimens by considering the T‐stress term in calculation of strain energy density. Furthermore, some researchers showed that the third terms of Williams series expansion have considerable influence on predicting the fracture resistance and fracture trajectory of the quasi‐brittle materials under mixed mode loading .…”

Application of artificial neural network for predicting crack growth direction in multiple cracks geometry

“…The student's t test result from correlation coefficient (r) of the test data sets are found to be 16.039 against the tabulated value of 2.86 for 99.5% confidence level and 19 degree of freedom for s-s-s-2 network architecture. Since t > t 0.995, 19 , it indicates that the correlation coefficient is significantly greater than zero at a 0.01 level. Similar tests were conducted for other combinations also.…”

“…The crack growth direction for two edge cracks on one side with initial conditions a 1 /a 2 = 1, H/a ≥ 1 and S/a = 0 is found to be less than 10 • . According to MTS [4,19], SED [15][16][17][18], DET [36] criterion, the crack extension angle  0 remains less than 10 • for K I /K II >10. This indicates that crack grows mostly under the influence of mode I and the effect of mode II stress intensity factor is about 1/10th of mode I and hence the effect of mode II is negligible as compared to mode I.…”

“…These effects have been investigated experimentally by the technique of photoelasticity in both mode I and mode II loading conditions. Ayatollahi and Sedighiani [19] studied the effect of T-stress on the critical mode I stress intensity factor of brittle and quasi-brittle materials. The minimum strain energy density criterion was revisited to take the effect of T-stress into account.…”

Fracture behaviour of notched round bars made of PMMA subjected to torsion at −60°C

“…Therefore, proposed fracture criteria are based on critical values of some macroscopic stresses [1], critical virtual cracks [2][3][4][5], non-local averaged parameters [6], stress intensity factors [7][8][9][10][11][12], notch rounding approach [13,14], strain energy density (SED) [15][16][17][18][19][20][21], J-integral [22,23] and Cohesive Zone Models [24][25][26][27][28][29].…”