High cycle fatigue life prediction and reliability

Authors: Junhong Zhang Jiewei Lin Guichang Zhang Hai Liu

Publish Date: 2012/12/07

Volume: 18, Issue: 6, Pages: 456-464

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Abstract

Based on the nonlinear continuum damage model CDM developed by Chaboche a modified model for high cycle fatigue of TC4 alloy was proposed Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature Then the material parameters needed in the CDM were obtained by the fatigue tests and the stress distribution of the specimen was calculated by FE method Compared with the linear damage model LDM the damage results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM By applying the CDM developed in this study to the life prediction of aeroengine blades it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles Finally the Cox proportional hazard model of survival analysis was applied to the analysis of the fatigue reliability The Cox model takes the covariates into consideration which include diameter weight mean stress and tensile strength The result shows that the mean stress is the only factor that accelerates the fracture process

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