Method of evaluating the cyclic fracture toughness of low-carbon steels

Abstract

In recent ye a r s , s e v e r a l organizat ions have conducted a large number of studies involving evaluation of the r e s i s t ance of s tee l to c r a c k growth under cycl ic loading (cyclic f r ac tu re toughness). The volume of such studies is i nc reas ing both in the USSR and abroad. It should be noted that no common method for obtaining and analyzing expe r imen ta l data has yet gained acceptance. This c i r cums tance is a ser ious obstacle to rapidly ac cumulat ing resu l t s lending t hemse lves to unambiguous in terpre ta t ion . Fatigue c r ack growth ra te has been studied on both spec imens and actual s t ruc tu res . All of the t e s t s have been conducted at a const2.nt m a x i m u m load, i .e . , with an ampli tude of s t r e s s intensi ty f ac to r that cont inuously i n c r e a s e s during c r a c k growth.