METHOD FOR ESTIMATING LIFE OF MATERIAL AND METHOD FOR ESTIMATING THERMAL FATIGUE LIFE OF MATERIAL

PROBLEM TO BE SOLVED: To provide a method for estimating a life of a material a structure of which is changed under an environment where it is used. SOLUTION: The method is to estimate a life of a material at least one of a characteristic and a strength of which is changed under a use environment. The method comprises a load information formation process wherein information including a relation of a size Q of a load impressed to the material and a cycle number N is obtained, a failure load information formation process wherein information including a relation of a size (failure strength) Q* of a load impressed when the material fails and the cycle number N is obtained based on the load information obtained in the load information formation process, and an estimation process wherein a life of the material is estimated from the load information of the material based on the failure load information. The method is suitable to estimate a thermal fatigue life of a material, e.g. an age-hardening type aluminum alloy containing Si which accompanies a structural change under the use environment and changes its characteristic or strength.