Low cycle fatigue stress-strain relation model of cyclic hardening or cyclic softening materials

Low cycle fatigue tests were carried out by the authors using a number of fatigue specimens of LY12CZ aluminum alloys, annealed 40CrNiMoA alloy steels and BHW35 pressure vessel steels which are of monotonic cyclic hardening or softening property, respectively. The concept of cyclic hardening or softening factor was proposed and the quantitative description was made with respect to the cyclic hardening or softening process. The stress-strain relation model of its process was presented. The test results are in agreement with the above model. (C) 1996 Elsevier Science Ltd.