摘要:
常规武器的战斗部主要由柱形装药和壳体两部分组成,而壳体会影响爆炸波的峰值以及衰减规律,因此明确混凝土中带壳装药爆炸应力波的衰减规律是结构抗爆设计需解决的问题。本文基于Kong-Fang混凝土材料模型和LS-DYNA中的多物质ALE算法,开展了CF120混凝土中带壳柱形装药爆炸波衰减规律的数值模拟研究。首先基于课题组前期开展的柱形装药埋置爆炸试验,对数值算法和材料模型参数进行验证;在此基础上主要分析了完全封闭爆炸和部分埋置爆炸条件下装药形状和壳体厚度对峰值应力的影响规律;最后利用数值模拟数据拟合出混凝土中带壳柱形装药爆炸波峰值应力的计算公式。研究结果表明:带壳装药爆炸近区,长径比越大,峰值应力越大,远区则相反,且壳体越厚,峰值应力越大,但存在一个阈值;并通过定义长径比系数、壳厚比系数以及峰值应力耦合系数定量描述了装药形状、壳体厚度和埋深对峰值应力的影响规律,且建立的爆炸波峰值应力计算公式可实现对不同长径比、不同壳体厚度和不同装药埋深的带壳柱形装药爆炸波峰值应力的快速预测,可为结构抗爆设计提供依据。
Abstract:
The warhead of conventional weapons is usually composed of a cylindrical charge and a metal case, in which the metal case can affect the attenuation law of peak stress induced by explosion. Therefore, it is important for the blast-resistant design to clarify the attenuation law of stress waves in CF120 concrete induced by cylindrical cased charge explosion. Based on the Kong-Fang concrete material model and the Multi-material Arbitrary Lagrangian Eulerian (MM-ALE) algorithm available in the LS-DYNA, the attenuation law of stress waves in concrete subjected to cylindrical cased charge explosion was numerically investigated in this paper. Firstly, the numerical algorithm and material model parameters were validated against two sets of cylindrical charge explosion tests. Then a series of fully enclosed and partially buried cylindrical charge explosion numerical models were established, in which different aspect ratios, shell thicknesses, and charge buried depths were considered as to analyze the influence of charge shape and shell thickness on stress waves in concrete. Finally, an empirical formula for peak stress of compression wave in concrete induced by cylindrical cased charge explosion was presented based on curve-fitting the numerical data. Numerical results demonstrated that the larger the aspect ratio, the higher the peak stress in the near region, while the opposite law holds for the far region. Besides, increasing the shell thickness will make the peak stress higher, but there is a threshold. The influence of charge shape, shell thickness, and charge buried depth on the peak stress can be quantified by defining the length-diameter ratio, thickness-diameter ratio, and coupling factor of peak stress. The empirical formula for peak stress of compression wave in concrete was demonstrated valid for varied aspect ratio, shell thickness, and charge buried depth, which can provide a reliable reference for blast-resistant design to estimate the peak stress induced by cylindrical cased charge explosion.