Vibration response experimental verification and fatigue analysis of thin-walled structures to thermal-acoustic loads
SHA Yundong;WANG Jian;ZHAO Fengtong;LUO Li;Liaoning Key Laboratory of Advanced Measurement and Test Technology for Aviation Propulsion System,Faulty of Aerospace Engineering,Shenyang Aerospace University;
Metallic thin-walled structure under thermal-acoustic environment shows complex nonlinear vibration response characteristics of large deflection,affecting fatigue performances and life of structure.Thermal-acoustic responses of superalloy thin-walled rectangular plates with four edges clamped were calculated by combining finite element method and reduced order modal method.Research showed that buckling structures could exhibit snapthrough motions which were decided by relative strength between thermal loads and acoustic loads,and stress cycle showed a triangular distribution.The Miner linear accumulative damage theory was employed in conjunction with improved rain flow counting method and Morrow mean stress model to calculate thermal-acoustic fatigue life.From pre-buckling to critical buckling,the damage level of stress cycle increased significantly from 10-5 to 10-4,and with the increase of temperature,the fatigue life showed a trend of decrease at first and then increase.The thermal-acoustic experiment of thin-walled structure was carried out to makeacomparison between the results of simulation and experiment.Results showed that the deviation of structural modal frequencies was less than 1 Hz,and strain responses of calculation and experiment results had a good alignment,validating the effectiveness of calculation method and model to thermal-acoustic responses.
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