星型-箭头蜂窝结构的面内动态压溃行为

In-plane dynamic crushing of star-arrowhead honeycomb structure

  • 摘要: 基于内凹机制,将星型和双箭头蜂窝的微结构巧妙结合,提出了一种新型拉胀蜂窝模型(简称星型-箭头蜂窝(SAH))。基于该模型,采用ANSYS/LS-DYNA有限元分析软件对其在不同冲击速度和不同相对密度下的变形模式进行了数值模拟研究。结果表明,在星型蜂窝(SSH)中加入箭头蜂窝的微结构将会减弱较低速度下动态压缩SSH时出现的局部"颈缩"现象,使SAH靠近冲击端附近出现了明显的"菱形"变形带,并具有更长的平台区和更高的平台应力。此外,在不同冲击速度下SAH单位质量的吸能值均大于SSH。详细讨论了冲击速度和相对密度对SAH平台应力的影响规律,并给出了平台应力的经验计算公式。

     

    Abstract: A novel honeycomb was proposed by adding double arrowhead cells into star-shaped honeycomb (SSH), and named as star-arrowhead honeycomb (SAH). The dynamic crushing behaviors and energy absorption capacities of the evolved structure SAH were systematically studied by finite element method with the commercial software package ANSYS/LS-DYNA explicit code. Adding double arrowhead cells into SSH improves the localized necking deformation of SSH under the low-velocity impact, enhances plateau stress, and makes a rhombus-shape band forming near the impact end. The results of finite element simulations show that SAH can absorb much more energy per unit mass than SSH under different impact velocities. Furthermore, the effects of the relative density and the impact velocity on the plateau stresses of SAH were discussed, and the empirical formula of plateau stress of SAH is given.

     

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