冲击载荷作用下颗粒材料动态力学响应的近场动力学模拟

发布时间：2018-12-26 14:46

【摘要】：颗粒材料在冲击载荷作用下的动态力学行为是学术界关注的热点问题.新近问世的近场动力学(peridynamics)理论将材料视为由大量有限体积和有限质量的物质点组成,基于非连续性和非局部作用假定建模,建立空间积分形式的运动方程,自然适应于颗粒材料动态力学行为的描述与分析.发展了描述颗粒间接触作用的物质点尺度的排斥力模型,考虑近场动力学方法中非局部长程力特征,改进了近场动力学中的初始微观弹脆性(prototype microelastic brittle,PMB)模型的本构力函数,并消除了原PMB模型中存在的"边界效应"问题.计算分析了冲击载荷作用下碳化钨陶瓷颗粒体系的动态力学响应,得到了不同冲击速度下颗粒体系的冲击波速,PD计算结果与试验结果高度一致;通过颗粒物质点尺度作用描述单颗粒尺度的接触作用,很好地再现了颗粒的转动与平动、颗粒挤压变形以及颗粒破碎等现象;刚性冲击板附近同时存在严重的颗粒破碎与轻微的颗粒损伤,远离冲击板的部分颗粒出现破损,且颗粒破碎主要是由颗粒间挤压、碰撞以及相对滑动剪切作用造成的.研究结果表明,所发展的计算模型和分析方法能很好地反映颗粒材料动态力学行为,具有广泛的应用价值.
[Abstract]:The dynamic mechanical behavior of granular materials under impact loads is a hot issue in academic circles. The recently developed (peridynamics) theory of near-field dynamics regards materials as consisting of a large number of points of matter of finite volume and finite mass. Based on the assumption of discontinuity and nonlocal interaction, the equations of motion in the form of spatial integral are established. It is naturally adapted to the description and analysis of dynamic mechanical behavior of granular materials. The repulsive force model at point scale for describing the contact between particles is developed. The constitutive force function of the initial microscopic elastic-brittle (prototype microelastic brittle,PMB) model in near-field dynamics is improved by taking into account the non-local long term force characteristics of the near-field dynamic method. The "boundary effect" problem in the original PMB model is eliminated. The dynamic mechanical response of tungsten carbide ceramic particle system under impact load is calculated and analyzed. The shock wave velocity of the particle system under different impact velocities is obtained. The calculated results of PD are in good agreement with the experimental results. The particle size function is used to describe the contact action of single particle scale, which can well reproduce the phenomena of particle rotation and translational motion, particle extrusion deformation and particle breakage. There are serious particle breakage and slight particle damage in the vicinity of rigid impact plate, and some particles far away from the impact plate are damaged, and the particle breakage is mainly caused by squeezing between particles, collision and relative sliding shear. The results show that the developed computational models and analytical methods can well reflect the dynamic mechanical behavior of granular materials and have wide application value.
【作者单位】：河海大学力学与材料学院工程力学系;
【基金】：国家自然科学基金(11372099,11132003,51179064) 江苏省自然科学基金(BK20151493)资助项目
【分类号】：O347.7

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