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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (1): 224811-224811.doi: 10.7527/S1000-6893.2020.24811

• Solid Mechanics and Vehicle Conceptual Design • Previous Articles     Next Articles

Fatigue experiments and lifetime for post-impact sheets of aluminum-alloys(AAs) under block spectrum loading

ZHANG Yibo1, CHEN Di2, CHENG Zhengqiang2, SHEN Peiliang1, XIONG Junjiang2   

  1. 1. Airframe Integration Department, Shanghai Aircraft Design and Research Institute, Shanghai 201210, China;
    2. School of Transportation Science and Engineering, Beihang University, Beijing 100083, China
  • Received:2020-09-29 Revised:2020-11-30 Online:2022-01-15 Published:2020-11-27
  • Supported by:
    National Natural Science Foundation of China(51875021)

Abstract: Tests of low velocity impact are performed on the sheets of AAs 2524-T3 and 7075-T62, respectively, with four different impact forces, and static and fatigue experiments are conducted on the intact and post-impact sheets under static tensile, constant amplitude and block spectrum loading. The impact-dent size, static and fatigue properties, and spectrum-loading life are determined, with the effect of impact on fatigue characteristics and damage mechanism analyzed and discussed from fractographic and experimental observations. An S-N-Kt surface model is proposed to depict fatigue characteristics for fatigue lifetime prediction of post-impact sheets subjected to block spectrum loading. A new concept is applied for experimental data and a reasonable agreement obtained between the theoretical and experimental results, demonstrating the effective and practical use of the developed surface model. A nonlinear elastic-plastic FE model based on the Johnson-Cook constitutive equation is generated to model the residual stress patterns and stress concentration around the impact-dent, and fatigue lives of post-impact sheets of AAs 2524-T3 and 7075-T62 subjected to block spectrum loading are predicted from the S-N-Kt surface model. Good agreements have been achieved between predictions and experiments.

Key words: fatigue, low velocity impact, aluminum-alloy sheet, lifetime, block spectrum loading

CLC Number: