In order to improve the crashworthiness of thin-wall structure,an improved Johnson-Cook material constitutive model was proposed.Combined with numerical calculation and intelligent algorithm,the thin-wall open-hole structure optimization design of aviation aluminum alloy was carried out.Firstly,the static and dynamic compression tests of 7150-T6 aviation aluminum alloy are carried out,and the results show that the material has significant strain rate sensitivity.Secondly,based on the static and dynamic mechanical properties of materials,an improved Johnson-Cook model is proposed,and the experimental results show that the model can better describe the dynamic mechanical behavior of materials.Thirdly,combined with the improved constitutive model and the split Hopkinson pressure bar experiment,an effective and reliable finite element model of the axial impact of thin-walled circular tube Hopkinson bar is established,and the influence of rectangular holes with equal distance on crash-resistance and maximum peak load of thin-walled circular tube members are discussed.Finally,genetic algorithm is used to carry out the multi-objective optimization design of aviation aluminum alloy thin-walled circular tube with open hole,and the optimization results are verified by experiments.The results show that the improved J-C model can well describe the plastic flow stress characteristics of 7150-T6 aviation aluminum alloy under different strain rates,and the optimized open-hole circular tube has good crash resistance and stable deformation mode,which can provide an effective way for design and performance research of thin-walled structure.
关键词
7150-T6航空铝合金/结构优化/Johnson-Cook本构模型修正/SHPB试验
Key words
7150-T6 aviation aluminum alloy/structure optimization/Johnson-cook constitutive model modification/SHPB experimental
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