船体水下近距非接触爆炸损伤计算之两步迭代法

船体水下近距非接触爆炸产生的破口计算过程复杂，涉及船体板架、武器装药和爆距方位等诸多因素，工程实践中通常应用经验公式求解。基于舰船遭受定向型战斗部攻击、毁伤面近似垂直于毁伤轴和爆炸过程瞬时发生满足近似能量守恒基本条件，根据爆炸冲击波初始动能与爆炸作用区域结构塑性变形能等量传递的假设，给出了计算方法。考虑了附着加强筋的船体壳板等效厚度对抵御冲击波毁伤的影响，运用爆炸冲击波作用下船体壳板产生的极限应变超过板材动态极限应变导致壳板开裂这一基本原理，设计了两步迭代法计算流程，给出了简捷易用的迭代计算表格。针对4种典型装药当量冲击波作用下，5～20 m长度舱段，11 m以内爆炸距离，6和8 mm这2种典型厚度船体壳板遭受爆炸冲击受损情况进行了768组数据计算。引入平面拟合方程，通过判断截平面相似度分析，给出了计算方法的适用性判据，探讨了计算参数的适用范围，以保证两步迭代法能够客观反映水下近距非接触爆炸的实际破坏效果。结合经验公式计算结果和破损舰船受损实测数据，对该方法进行了检验，实践表明：两步迭代法易于工程实践且具有较好的准确性。

A two-step iterative method for damage calculation of a ship hullsubjected to underwater close-up non-contact explosion

The calculation of the break of ship hull caused by underwater close-range non-contact explosion is a complex process, involving many factors such as the hull frame, weapon charge, explosion distance and orientation, etc., so empirical formulas are usually used in engineering design. If the ship is attacked by a directional warhead, it is usually assumed that the damage surface is approximately perpendicular to the damage axis, and the explosion process instantaneously meets the basic condition on approximate energy conservation, then the calculation method is proposed according to the assumption that the initial kinetic energy of the explosion shock wave is equally transmitted to the plastic deformation energy of the structure in the explosion action area. Considering the effect of the equivalent thickness of the hull shell-plate attached with stiffeners on the resistance to shock wave damage, and using the fundamental principle that cracking of the shell plate will take place when the ultimate strain of the hull plate under the action of explosion shock wave exceeds the dynamic ultimate strain of the plate, the calculation flow of the two-step iterative method is designed, and a simple and easy-to-use iterative calculation table is given. 768 sets of data are calculated for the damage of hull shell-plates with the typical thicknesses of 6 mm and 8 mm under the action of four typical charge equivalent shock waves, with an explosion distance within 11 m, acting on a compartment with 5-20 m span. By introducing the plane fitting equation, the applicability criterion of the calculation method is given by judging the similarity analysis of the section plane, and the valid range of the calculation parameters is discussed to ensure that the two-step iteration method can objectively reflect the actual damage effect of the underwater short-range non-contact explosion. Combined with the calculation results of empirical formulas and the measured data of damaged ships, the method is verified. The practice shows that the two-step iterative method is easy for engineering practice and has good accuracy.