T-stress evaluations of mixed mode I/II fracture specimens and T-effects on mixed mode failure of aluminium

Abstract

B y aid of Eshelby's theoretical development, and through the use of a direct line integration procedure for the evaluation of the required path-independent integrals. T-stress calculations have been carried out on a number of mixed mode loading configurations. These involved the obliquely cracked SEN specimen, chosen as a test case, and, from the testing point of view, more suitable Arcan specimen and a version of the CTS specimen. Generally excellent agreement was found between the present results and those of previous investigators. However, results obtained under mixed-mode conditions using direct comparison of field quantities showed large discrepancies, suggesting such methods may be hazardous. A study of the T-stress term in conjunction with mixed-mode failure of aluminium 7075-T6 was also conducted. In applying the numerical results on previously reported experimental data, along with complementary experiments performed under vanishing T-stress conditions it was, however, found that the observed geometry and size dependence could not be explained by this additional term.

Analysis of experimental factors in elastic–plastic small specimen mixed‐mode I‐II fracture mechanical testing

“…where σ fs and τ fs denote the tensile and shear flow stresses, respectively. Because a blunting line defines the state between deformation and crack extension, one can, based on micromechanical considerations on factors controlling the rupture process, write a blunting line as a combination of mixed‐mode fracture criteria (combination of maximum shear and hoop stress criteria for non‐linear elastic material using the modified HRR field; for background see Refs [23,24]): 25…”

Quantification of constraint effects in fracture mechanism transition for cracked structures under mixed mode loading

“…Loading continued until the maximum load was achieved when fracture occurred. The failure type, tensile or shear, was identified by examination of the fracture surfaces: tensile‐type fracture gave a rough surface while shear‐type fracturegave a smooth, shiny surface 1,18,19 . Accordingly, loading the long crack specimen in the first, second and third loading holes result in tensile‐type fracture while for short crack specimens just the first two loading holes lead to tensile‐type fracture.…”

An investigation on the effects of equal channel angular pressing on the mixed‐mode fracture toughness and mechanical properties of 6063 aluminium alloy

“…The mixed-mode SIFs were obtained from the following equations 39 : Mixed-mode fracture toughness is noted as K t when calculated versus fracture load.…”