Aim. Having pointed out that past research relies too much on empirical data, we try to explore what we believe to be a better method through somewhat more theoretical analysis. Sections 1 through 3 of the full paper explain in some detail the better method we explored. Its core consists of: (1) we utilize a constitutive relationship to express the stress-strain responses of high-density PUR (polyurethane) foams under uniaxial compression loading conditions; (2) we modify the constitutive relationship and derive eq. (4) in the full paper to do the numerical analysis of the missile's vertical water-entry impact. To validate the effectiveness of our method, we compare the effects of the different geometrical coefficients of the mitigator, the different densities of PUR foams and different water-entry velocities on dynamic cushioning performances. The comparison results, given in Figs. 4 through 9, show preliminarily that our method is more effective than the conventional method for accurately analyzing water-entry impact.%缓冲器可以减少和控制雷弹入水冲击载荷,提升空投雷弹的耐撞性和安全性.文中引进聚氨酯泡沫塑料在冲击加载条件下的本构关系式,代替传统的EPRC三段式经验模式,同时,为了满足整个时域的连续性和可计算性,对本构关系式进行相应的修正,然后参与雷弹入水冲击运动方程的数值计算.算例分析了垂直姿态入水情况下缓冲器的动态缓冲性能,同时分别对不同泡沫塑料的密度和入水速度下的缓冲效果进行分析,最后给出具有不同外型参数雷弹的入水冲击载荷规律.分析结果表明:与传统的经验方法相比,文中方法更符合实际情况,简便且通用性强,可以用于雷弹入水冲击的耐撞性结构设计和分析.
展开▼
