過大荷重後の疲労き裂伝ぱの遅延挙動の体積力法による解析

概要

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By using the extended body force method, a simulation analysis of fatigue crack propagation was carried out to investigate the delaying effects of overloads on fatigue crack propagation. It is shown that the transitional behavior of fatigue crack propagation after overloads can be demonstrated by the analytical results of the plasticity induced crack closure. The crack closure behavior after overloads was explained simply by taking into account the changes in δ^<max>_<tip> and δ_<R,tip> during the transitional process, where δ^<max>_<tip> is the crack tip opening displacement at the fully loaded state and δ_<R,tip> is the total thickness of the stretched meterial remaining on the upper and lower surfaces at the crack tip. The retardation of crack propagation due to overloads was discussed quantitatively based on the results of the present calculation. For the single peak overloads the δ^<max>_<tip> just after the peak overload is proposed to correlate the number of delay cycles for various combinations of load levels.
社団法人日本機械学会の論文
1986-09-25