The effect of impact loadingon crack propagation in forgedsteel EA4T

This paper presents the results of the experimental and analytical investigation carried out using a steel forged material، EA4T، subjected to impact loading conditions within the strain rate domain101-103 (1/s). The standard three point bend test specimens manufactured according to ASTM 399 standard were subjected to impact loadlevels correspondingto preset defined impact energy levels by applying the Izod impact testing equipment. The specimens were also modeled and the loading condition was simulated using the finite element commercial software، ABAQUS v6. 11. Both the experimental findings and the finite element analysis results indicated that the crack initiation conditions were satisfied when the impact energy applied to the specimen reached a specifiedlevel. It was found that for a lower level of applied impact energy، the impact loading resulted in improving the fatigue characteristic of the material. In contrast، application of the higher impact energy caused the crack to propagate further. The other finding of the study was that increasing the plastic zone size decreased the crack propagation rate (da/dE).