Experimental and numerical investigations of crack behavior and life prediction of 18Cr2Ni4WA steel subjected to repeated impact loading

• The repeated impact tests were conducted using notched and unnotched specimens.
• The simulation method of progressive failure under repeated impacts was provided.
• The notch sensitivity and crack growth rate in repeated impacts was investigated.
• The features of energy absorption per impact versus impact number are provided.
• An empirical formula was proposed to predict the number of impacts to failure.

To predict the residual life of structure under repeated impacts, the crack behavior of standard specimens with and without notch were studied experimentally and numerically. The history of crack propagation and energy absorption was recorded, and the fracture surface appearance was observed experimentally. A energy-based life prediction method for repeated impacts was proposed and validated by experiments, which includes the effects of strain rate and cumulative damage. It is found that structures under repeated impacts are extremely sensitive to notch or crack. With the increasing number of impacts, both the ratio of plastic energy to elastic energy raises and finally approaches to infinite at fracture.