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Energy dissipation by axial crushing of tubes.

机译:通过轴向挤压管子来消耗能量。

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摘要

This study investigates the nature of energy dissipation in axial crushing of High Molecular Weight High Density Polyethylene (HMW/HDPE) circular tubes. In the process, formulas are developed for the prediction of peak and mean crushing loads including the effects of strain-hardening, strain-rate, and inelastic behavior. Possibility of using nested tubes for optimal performance as energy dissipation device is considered.;The prediction of peak axial crushing load of tubes is carried out by buckling and post-buckling analyses. The equivalent column approach is used in buckling analysis, and inelastic and strain-hardening effects are considered.;An upper-lower bound method is proposed to predict the mean crushing load. The upper bound of axial crushing load of tubes is predicted by post-buckling analysis, whereas the lower bound is predicted by plastic analysis. The mean axial crushing load is taken as the average of upper and lower bounds of the axial crushing load. It is found that the mean crushing load is affected not only by tube's geometric parameter, ;HMW/HDPE was found to be a strain-rate sensitive material and the constitutive relationship for it can be expressed either by Cowper and Symonds' equation or, in the logarithmic form. The strain rates of tubes in axial crushing in both circumferential and axial directions were found to be significant and hence needed to be accounted for in the prediction of effective strain rate. It was also found that strain rate does not vary linearly with the loading speed, as multiple folds are formed simultaneously under a high loading speed.;Energy dissipation characteristics of a group of nested tubes was found to be superior to that of a simple tube. The honeycomb arrangement avoids global buckling of long tubes, and concentrically nested tubes with different lengths enhance the mean crushing load and reduce the peak crushing load improving energy dissipation efficiency. The honeycomb structure with nested tubes is proposed for energy dissipation devices. The honeycomb structure with nested tubes is considered to be best suited for optimal design of energy dissipation devices based on axial crushing of tubes. Further study of this topic is needed.
机译:这项研究调查了高分子量高密度聚乙烯(HMW / HDPE)圆管轴向破碎过程中能量耗散的性质。在此过程中,开发了用于预测峰值和平均破碎载荷的公式,其中包括应变硬化,应变速率和非弹性行为的影响。考虑了使用嵌套管以获得最佳性能作为能量消散装置的可能性。;通过屈曲和后屈曲分析来预测管子的峰值轴向挤压载荷。屈曲分析采用等效柱法,考虑了非弹性和应变硬化效应。提出了一种上限-下限法来预测平均破碎载荷。通过屈曲后分析预测管的轴向挤压载荷的上限,而通过塑性分析预测下限。平均轴向破碎负荷取为轴向破碎负荷的上下限的平均值。发现平均破碎载荷不仅受管的几何参数影响; HMW / HDPE被认为是应变率敏感材料,并且其本构关系可以通过Cowper和Symonds方程或对数形式。发现管在圆周方向和轴向方向上的轴向破碎中的应变率是显着的,因此需要在有效应变率的预测中加以考虑。还发现应变率不随加载速度线性变化,因为在高加载速度下会同时形成多个褶皱。一组嵌套管的能量耗散特性要优于简单管。蜂窝状布置避免了长管的整体弯曲,并且不同长度的同心嵌套管提高了平均破碎负荷并降低了峰值破碎负荷,从而提高了能量消耗效率。提出了带有嵌套管的蜂窝结构用于能量消散装置。带有嵌套管的蜂窝结构被认为最适合基于管轴向挤压的能量消散装置的优化设计。需要对该主题进行进一步研究。

著录项

  • 作者

    Luo, Xiaohui Charlie.;

  • 作者单位

    Vanderbilt University.;

  • 授予单位 Vanderbilt University.;
  • 学科 Engineering Civil.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 103 p.
  • 总页数 103
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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