低サイクル疲労下における複数疲労き裂進展の相互作用に関する研究

概要

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The interaction of crack growth on multiple ended fatigue cracks is examined with the coupled compact tension specimens of 0.45% C carbon steel under high cyclic stresses. The crack propagation behaviour of coupled specimens fatigued under the stress ratio of 0.05 and 0.7 is compared with that of single specimen. The deviation of crack propagation rate from the stable relation between the rate and ΔK of a single specimen is found to take place with the difference of crack closure and the onset of the ratcheting extension of specimens. The crack growth acceleration is affected by another specimen coupled because of the incomplete reversal of plastic deformation in ratcheting deformation. Based on the theoretical prediction of an interaction curve for crack growth of a coupled specimen, it is concluded that multiple ended fatigue cracks under high cyclic stresses propagate with a mechanism such that the increment of total strain energy release per cycle in a body including some cracks is distributed to each crack with the ratio of the strain constraint factor.
社団法人日本機械学会の論文
1987-10-00