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Constitutive modeling of aluminum foam and finite element implementation for crash simulations.

机译：泡沫铝的本构模型和碰撞模拟的有限元实现。

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摘要

In the past decades metallic foams have been increasingly used as filler materials in crashworthiness applications due to their relatively low cost and high capacity of energy absorption. Due to the destructive nature of crashes, studies on the performance of metallic foams using physical testing have been limited to examining the crushing force histories and/or folding patterns that are insufficient for crashworthiness designs. For this reason, numerical simulations, particularly nonlinear finite element (FE) analyses, play an important role in designing crashworthy foam-filled structures. An effective and numerically stable model is needed for modeling metallic foams that are porous and encounter large nonlinear deformations in crashes.;In this study a new constitutive model for metallic foams is developed to overcome the deficiency of existing models in commercial FE codes such as LS-DYNA. The new constitutive model accounts for volume changes under hydrostatic compression and combines the hydrostatic pressure and von Mises stress into one yield function. The change of the compressibility of the metallic foam is handled in the constitutive model by allowing for shape changes of the yield surface in the hydrostatic pressure-von Mises stress space. The backward Euler method is adopted to integrate the constitutive equations to achieve numerical accuracy and stability. The new foam model is verified and validated by existing experimental data before used in FE simulations of crushing of foam-filled columns that have square and hexagonal cross-sections.
机译：在过去的几十年中，金属泡沫由于其相对较低的成本和较高的能量吸收能力而在防撞性应用中越来越多地用作填充材料。由于碰撞的破坏性，使用物理测试对金属泡沫的性能进行的研究仅限于检查压碎力历史和/或折叠模式，这些不足以进行耐撞性设计。因此，数值模拟，尤其是非线性有限元（FE）分析，在设计耐撞泡沫填充结构中起着重要作用。需要一种有效且数值稳定的模型来建模多孔且在碰撞中遇到较大非线性变形的金属泡沫。；本研究中，开发了一种新的金属泡沫本构模型，以克服商业有限元代码（例如LS）中现有模型的不足-戴娜新的本构模型考虑了静水压力下的体积变化，并将静水压力和von Mises应力组合为一个屈服函数。通过允许静水压力-冯·米塞斯应力空间中屈服面的形状变化，在本构模型中处理金属泡沫的可压缩性变化。采用后向欧拉方法对本构方程进行积分，以实现数值精度和稳定性。在用于具有正方形和六边形横截面的泡沫填充柱的破碎的有限元模拟之前，新的泡沫模型已通过现有的实验数据进行了验证和验证。

著录项

  • 作者

    Bi, Jing.;

  • 作者单位

    The University of North Carolina at Charlotte.;

  • 授予单位 The University of North Carolina at Charlotte.;
  • 学科 Engineering General.;Engineering Materials Science.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2012
  • 页码 143 p.
  • 总页数 143
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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