A novel two-scale nonlinear damage accumulation model for vibration fatigue life prediction

Abstract

Vibration is the main factor causing high cycle fatigue. The macro-response stress and strain of the structure under the excitation of vibration load are generally in the elastic stage. However, fatigue failure still occurs due to long-term cyclic load, which is unexplainable by the macro-plastic accumulation method. Therefore, a two-scale nonlinear damage accumulation model is proposed for vibration fatigue based on the physical characteristics of multi-scale fatigue damage evolution. In this model, two-scale elastic-plastic constitutive equations based on the equivalent inclusion theory are built, and a two-stage damage accumulation strategy with two critical damages is designed. A resonance fatigue life prediction algorithm is established based on the proposed model, and a validation test is carried out using the cantilever beam made of GH4169 alloy. The results show that the deviation between the vibration fatigue life prediction and test results is within a scatter band of factor 2, indicating that the two-scale nonlinear damage accumulation model is effective in the vibration fatigue region.