Abstract The effect of the parameters of the Johnson and Cook material model on the direct impact crushing behaviour of a layered 1050 H14 aluminium corrugated structure was investigated numerically in LS-DYNA at quasi-static (0.0048 m s−1) and dynamic (20, 60, 150 and 250 m s−1) velocities. Numerical and experimental direct impact tests were performed by lunching a striker bar onto corrugated samples attached to the end of the incident bar of a Split Hopkinson Pressure Bar set-up. The numerical impact-end stress-time and velocity-time curves were further compared with those of rigid-perfectly-plastic-locking (r-p-p-l) model. Numerical and r-p-p-l model impact-end stress analysis revealed a shock mode at 150 and 250 m s−1, transition mode at 60 m s−1 and quasi-static homogenous mode at 20 m s−1. The increase of velocity from quasi-static to 20 m s−1 increased the numerical distal-end initial peak-stress, while it almost stayed constant between 20 and 250 m s−1 for all material models. The increased distal-end initial peak-stress of strain rate insensitive models from quasi-static to 20 m s−1 confirmed the effect of micro-inertia. The numerical models further indicated a negligible effect of used material models on the impact-end stress of investigated structure. Finally, the contribution of strain rate to the distal-end initial peak-stress of cellular structures made of low strain rate sensitive Al alloys was shown to be relatively low as compared with that of strain hardening and micro-inertia, but it might be substantial for the structures constructed using relatively high strain rate sensitive alloys.

中文翻译：

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细胞壁材料应变和应变率硬化行为对铝多层波纹芯动态压碎响应的影响

摘要 在 LS-DYNA 中，在准静态 (0.0048 ms−1) 和动态 (20, 60 , 150 和 250 ms−1) 速度。数值和实验直接冲击测试是通过将撞杆放在波纹样品上进行的，这些样品连接到分体霍普金森压力杆装置的入射杆末端。将数值冲击端应力-时间和速度-时间曲线与刚-完美-塑性-锁定 (rppl) 模型的数值进行了比较。数值和 rppl 模型冲击端应力分析揭示了 150 和 250 m s-1 处的冲击模式、60 m s-1 处的过渡模式和 20 m s-1 处的准静态均匀模式。速度从准静态增加到 20 m s-1 增加了数值远端初始峰值应力，而对于所有材料模型，它几乎在 20 到 250 ms-1 之间保持不变。应变率不敏感模型的远端初始峰值应力从准静态增加到 20 ms-1，证实了微惯性的影响。数值模型进一步表明所用材料模型对所研究结构的冲击端应力的影响可以忽略不计。最后，与应变硬化和微惯量相比，应变率对低应变率敏感铝合金蜂窝结构的远端初始峰值应力的贡献相对较低，但可能很大对于使用相对高应变率敏感合金构造的结构。