Reliability of the chevron-notch technique for fracture toughness determination in glass

摘要: Abstract The applicability of the chevron-notch (CN) three-point bending test for determining fracture toughness (KIc) borosilicate glass was studied. As-received specimens with straight sharp notch were also tested in comparison purposes. It found that both chevron and notched specimen geometries equally suitable determination terms average values data variability according to Weibull Student's t-statistics. Further testing CN geometry showed annealing at a temperature (550 °C) higher than transformation led lower value KIc. difference mean (0.75 0.64 MPam1/2 before after annealing, respectively), ascribed different level compressive residual stresses samples. t-test applied confirm statistical significance KIc measured. These results demonstrate technique is well-suited reproducible accurate glass.