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FATIGUE CRACK GROWTH UNDER MODE II LOADING
Author(s) -
Wang M. O.,
Hu R. H.,
Qian C. F.,
Li J. C. M.
Publication year - 1995
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1995.tb00867.x
Subject(s) - materials science , crack closure , fracture mechanics , paris' law , crack growth resistance curve , crack tip opening displacement , austenite , mode (computer interface) , composite material , cruciform , alloy , bifurcation , structural engineering , metallurgy , microstructure , engineering , physics , nonlinear system , quantum mechanics , computer science , operating system
— The behavior of fatigue crack growth for low and medium carbon steels, an austenitic stainless steel and an aluminum alloy under pure Mode II loading was investigated experimentally, using cruciform specimens. The results show that under pure Mode II loading, fatigue crack propagation has three possibilities, namely, bifurcation into two branches, propagation along the original Mode II direction, and the mixture of these two situations, depending on the material. The growth rate da/dN vs. Δ K II relation for Mode II propagation is similar to a Pans type law for Mode I growth. Fractographic observations by optical microscopy and SEM were made also on all specimens tested. When a crack branched, striations parallel to the crack front which were often associated with Mode I fatigue crack growth were observed and long marks parallel to the crack propagation direction were also found for slanted fracture surfaces. When a crack propagated along the original Mode II direction, many frictional marks parallel to the crack propagation direction were observed.