Multiaxial Fatigue Damage Parameter and Life Prediction without Any Additional Material Constants

Zheng-Yong Yu,Shun-Peng Zhu,Qiang Liu,Yunhan Liu

doi:10.3390/ma10080923

Zheng-Yong Yu, Shun-Peng Zhu + Show 2 more

Open Access

https://doi.org/10.3390/ma10080923

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Abstract

Based on the critical plane approach, a simple and efficient multiaxial fatigue damage parameter with no additional material constants is proposed for life prediction under uniaxial/multiaxial proportional and/or non-proportional loadings for titanium alloy TC4 and nickel-based superalloy GH4169. Moreover, two modified Ince-Glinka fatigue damage parameters are put forward and evaluated under different load paths. Results show that the generalized strain amplitude model provides less accurate life predictions in the high cycle life regime and is better for life prediction in the low cycle life regime; however, the generalized strain energy model is relatively better for high cycle life prediction and is conservative for low cycle life prediction under multiaxial loadings. In addition, the Fatemi–Socie model is introduced for model comparison and its additional material parameter k is found to not be a constant and its usage is discussed. Finally, model comparison and prediction error analysis are used to illustrate the superiority of the proposed damage parameter in multiaxial fatigue life prediction of the two aviation alloys under various loadings.

Highlights

Hot engine section components such as turbine discs and blades are often subjected to complex multiaxial cyclic loads, and their life evaluation is of great importance for ensuring the reliability and structural integrity of aero engines [1,2,3,4]
It is necessary to develop a simple and efficient multiaxial fatigue life prediction damage parameter without any additional material constants that are applicable for a variety of metal materials and loading conditions
Model with an additional material parameter is widely recognised to have a good life prediction ability, which is introduced for model comparison

Summary

Introduction

Hot engine section components such as turbine discs and blades are often subjected to complex multiaxial cyclic loads, and their life evaluation is of great importance for ensuring the reliability and structural integrity of aero engines [1,2,3,4]. The multiaxial fatigue life prediction models can be summed up into the following categories: the equivalent stress/strain models, energy-based criteria, damage mechanics-based models [18,19,20,21] and critical plane approaches [22,23,24]. It is necessary to develop a simple and efficient multiaxial fatigue life prediction damage parameter without any additional material constants that are applicable for a variety of metal materials and loading conditions. Chu’s model averages the contribution from tensile behavior and shear behavior and provides an average crack direction of 22.5◦ as the critical plane [24,33] This cannot really reflect the multiaxial fatigue of various load paths. The primary focus of the current work is to present a simple and efficient multiaxial fatigue damage parameter that is able to predict fatigue life under various load paths.

Fatemi–Socie Model

Proposed Multiaxial Fatigue Damage Parameter

Materials and Multiaxial Fatigue Data

Discussion on the Additional Material Parameter of the FS Model

Model Validation and Comparison

5.5.Conclusions