爆炸载荷下正弦曲边三维负泊松比夹芯板的动态响应和吸能特性

Dynamic response and energy absorption properties of sinusoidally curved three-dimensional negative Poissonʼs ratio sandwich panels subjected to blast loading

具有优异能量吸收特性的负泊松比结构在抗爆炸冲击防护领域有广阔的应用前景。为进一步提升夹芯板的抗爆性能,提出了一种在X、Y方向力学特性相同的正弦曲边三维负泊松比夹芯板用于防爆保护。采用数值模拟方法,对夹芯板在空爆载荷下的动态响应和吸能特性进行了研究,分析了夹芯板塑性拉伸和弯曲对背面板变形模式和轴向偏转分布的影响,并探究了爆炸距离、炸药质量、面板厚度和芯层关键结构参数对夹芯板变形和能量吸收的影响。结果表明,在空爆载荷下,夹芯板的动态响应过程可分为芯层压缩、整体变形和自由振动3个阶段。后面板在纵向(X方向)和横向(Y方向)上的抗变形能力无明显差异。随着炸药质量增加和爆炸距离减小,夹芯板的后面板中心位移增加,芯层吸能占比减小。此外,采用薄前面板和厚后面板的夹芯板可以提高芯层的吸能占比。当分别增加相同的前、后面板厚度时,前面板厚度对减小后面板中心位移的影响更显著。当芯层厚度从0.6 mm减小至0.2 mm时,后面板中心位移减小49.0%,总能量吸收增加86.7%;芯层振幅从0.2 mm增大至1.0 mm时,后面板中心位移减小20.7%,总能量吸收大致不变;芯层高度从10 mm增大至18 mm时,后面板中心位移减小88.3%,总能量吸收增加56.9%;芯层宽长比从0.56减小至0.2时,后面板中心位移减小39%,总能量吸收增加47.4%。

The remarkable energy absorption properties of the negative Poissonʼs ratio structure offer extensive prospects for applications in blast protection.However,the existing in-plane configurations of two-dimensional auxetic honeycomb cores always represent anisotropic behavior.To further enhance the blast resistance of sandwich panels,a three-dimensional sinusoidal curved-edge sandwich panel with a negative Poissonʼs ratio effect in both the X and Y directions for blast protection was proposed.The dynamic response and energy absorption characteristics under air blast load were studied by numerical simulation.Deformation modes and axial deflection distribution caused by plastic stretching and bending of the back face sheet were investigated in detail.The effects of stand-off distance(SOD),explosive mass,panel thickness,and key geometric parameters of the core layer on deformation and energy absorption were discussed.The results show that the dynamic response process of the sandwich panel can be divided into three stages:core compression,overall deformation,and free vibration.Moreover,it is found that there is no significant difference in the ability to resist deformation of the sandwich structure along the longitudinal(X)and transverse(Y)directions.As the TNT mass increases and the SOD decreases,the central displacement of the back face sheet of the sandwich panel increases,leading to a decrease in the energy absorption ratio of the core layer.Furthermore,utilizing a sandwich panel with a thin front panel and a thick back panel can increase the energy absorption proportion of the core layer.When increasing the thickness of the front and back panels by the same amount,the thickness of the front panel has a more significant effect on reducing the center displacement of the back panel.When the core thickness decreases from 0.6 mm to 0.2 mm,the back panel center displacement decreases by 49.0%,and the total energy absorption increases by 86.7%.As the core amplitude increases from 0.2mm to 1.0mm,the back panel center displacement decreases by 20.7%,with the total energy absorption remaining roughly constant.With an increase in core height from 10mm to 18mm,the back panel center displacement decreases by 88.3%,and the total energy absorption increases by 56.9%.Furthermore,a decrease in core aspect ratio from 0.56 to 0.2 results in a 39%reduction in back panel center displacement and a 47.4%increase in total energy absorption.The results of this study can guide the design of energy-absorbing protection for sandwich panels.