Lifetime Assessment for Multiaxial High-Cycle Fatigue Using Twin-Shear Unified Yield Criteria

Abstract

In this paper, a life prediction model associated with maximum principal stress and equivalent shear amplitude based on twin-shear unified yield criterion for multiaxial high-cycle fatigue is proposed. The equivalent shear amplitude is the normalized format of the equivalent shear amplitude based on clusters of yield criteria embodying Tresca and the linearization of Huber-von Mises, extending the application to metallic materials. Simultaneously, the effect of mean stress on multiaxial high-cycle fatigue is considered in the proposed model. As an assessment of the new prediction model, the criterion is compared with experimental data of aluminum alloy LY12CZ and carbon structural steel SM45C published in the relevant literature, which shows that most of the data are located within an error range of less than two times the data and are in good agreement with the experiment. Moreover, the proposed model is also compared with other models, such as McDiarmid, Liu, and Freitas, to validate its competitiveness.

Thermal Stress Compensation for an Aircraft Engine Duct System Based on a Structural Redesign of Tie Rods

“…Since the above-established model involves elastic-plastic deformation and contact problems, Static Structural and its built-in Newton-Raphson method [31][32][33][34][35][36][37] were used to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”

“…to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”

“…Meanwhile, since the tee is located in the middle of the duct system, the effects produced by the three branches were superimposed, leading to a very obvious concentration of secondary stress. Moreover, as shown in Figures 10-12, with the temperature changing from 315.56 °C to 537.78 °C, the stress concentration phenomenon became more to calculate the von Mises stress of the duct system [38][39][40][41][42][43], and stress calculation results were obtained under the characteristic operating conditions of the duct system [44].…”