Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : December 22, 2018 - December 24, 2018
This paper discusses evaluation of fatigue life of low carbon steel, type 400 steel under proportional and non-proportional multiaxial random loading. Fatigue tests were carried out using a hollow cylinder specimen at room temperature and an electrical servo controlled hydraulic fatigue testing machine for push-pull and reversed torsion loading, of which maximum push-pull loading and torque are r50 kN and r500 Nm, was employed as testing machine. In the test, three types of stress paths, a push-pull, a reversed torsion and a circle were employed. The circle loading is a cyclic loading combing the push-pull and the reversed torsion loading in which axial and shear stress waveforms have 90 degrees phase difference. In addition, these fatigue tests were carried out by using random waveform which simulate actual using situation of construction machine. From the obtained test results, evaluation method combined IS (Itoh-Sakane) method, rain flow method and modified Miner's rule was effective. In Miner's rule, by considering reduction in fatigue limit due to non-proportional loading, the evaluation method was also effective. From observations of specimen surface afterthe constant amplitude tests around the fatigue limit, the validity of these evaluation method under non-proportional multiaxial random loading was clarified.
