DATA PROCESSING METHOD IN MATERIAL FATIGUE TEST

摘要

PURPOSE:To make it possible to evaluate the fatigue of a material in consideration of hysteresis energy by obtaining the plastic strain of each loop in the order of the strain peak values of the loops from the smaller value. CONSTITUTION:At first, a preset load having a random waveform is applied on a test piece 1. The data of strain which is applied on the test piece 1 and the data of the strain generated in the test piece 1 at this time are collected and stored in time series. Then, the stored strain data are searched, and the strain peak data of each loop formed in a stress-strain history curve is obtained and stored. Then, the central strain of the loop is obtained from the maximum stress value and the minimum stress value of the loop which are read out of the stored stress data. Thereafter, the strain value corresponding to the central stress is read out of the strain data, and the width of the plastic strain is obtained. Then, the width of the plastic strain is stored in correspondence with the peak value. The stress data and the strain data of the loop are changed into the same data outside the range wherein said data are present.