抄録
Fracture toughness tests on three-point and four-point mixed mode ( Mode I + Mode II ) bend specimens of an aluminum alloy A5083-0 have been conducted. The fractured surface and the cross section of the crack tip have been observed by a scanning electron microscope. For the four-point bend specimen, one corner of the crack tip was blunted and the other sharpened. the critical stretched zone width (SZWc) is different at the two corners, but the critical stretched zone length along the deformed tip (SZLc) has almost the same value for both Mode I and mixed mode conditions tested. The parameter SZL may be a useful elastic-plastic fracture parameter. A finite element analysis has been conducted to obtain the relationship between the J-integral and SZL, and the critical value of the J-integral under the mixed mode condition is discussed.
