On the Crack Propagation Behavior Under Varying Load : The Case for Al 2024-T 351 Alloy

Abstract

A simplified crack propagation model which takes into consideration the retardation effect was proposed in last report. It was confirmed that this model simulates the crack propagation behavior of SM58Q steel under quasi-random load very well. In the present report, the applicability of this model to Al 2024-T351 alloy was investigated to examine the possibility of application of this model to various kinds of materials. The conclusions obtained mainly were as follows ; (1) This model holds good to Al 2024-T351 alloy as to SM58Q steel, and range of applicability of this model to various kinds of material was increased. (2) The crack retardation effect in Al 2024-T351 alloy is greater than that in SM58Q steel. (3) In the quasi-random loading test, the smaller the load cycles in 1 block (ΔN) or the smaller the correlation factor (ρ) of random number, the greater the retardation effect becomes.