PARAMETER ANALYSIS FOR TIME-DEPENDENT LOW-CYCLE FATIGUE LIFE

Temperature and strain rate dependences of low-cycle fatigue life can be represented by a modified Larson-Miller parameter. The parameter P is written by P = T(logN(25)-Alog epsilon + B), where T is temperature , N-25 is fatigue life, epsilon is strain rate, and A and B are consta nts. In the analysis, each data of several kinds of engineering materi als from ferritic steels to austenitic stainless steels are used. Thes e are the authors original data published in the documents of NRIM Fat igue Data Sheets. The result of 304 stainless steel has been compared with statistical analysis result by Diercks adopted in a design code. The fatigue life curves represented by the proposed parameter analysis fitted well test data in high-cycle region as well as ones in low-cyc le region.