Abstract:

In order to set up life prediction equation of CP-type test, in accordance with current computational method of SEP or SRP, low cycle fatigue （PP-type） test and CP-type test must be conducted.However, the present paper shows that by the direct use of CP-type test and its data, but without using PP-type test data, and parameters in the life prediction equation of CP-type test can be obtained, based on method of least square and numerical optimization .This method, thus, saves test cost and simplifies procedures for establishing the equation of SEP model. It also lays the foundation for applying SEP model to conditions which can only be performed by CP-type tests, and expands the applicable range of SEP thereby.

Key words: strain energy, CP-type test, optimizing computation, life prediction