【作者】 赵凯；

【导师】 王肖钧；

【作者基本信息】 中国科学技术大学 ， 工程力学， 2007， 博士

【摘要】 成层式防护结构是当前我国人防工程的主要形式，在以空袭为主要打击手段的高科技战争背景下，如何改进成层式防护结构对各种导弹或航弹等武器爆炸后产生的冲击波的防护效果，是当前防护工程领域研究的重点课题。其中，利用应力波在分层介质中的传播原理对成层式防护结构的分层结构进行改造，进而分析爆炸波在结构中的传播规律以及结构的毁伤效应是本文的重点所在。其研究成果不但能够给成层式防护结构的改进和优化提供有益的理论和实践依据，而且对各种军事和民用中防护层的设计和推广有很大的参考价值，是一项极具学术意义和应用前景的课题。本文的主要研究内容如下：运用应力波在分层介质界面上的透反射原理，推导出弹性波在多层介质中的应力峰值和能量随材料波阻抗变化的传递规律，指出按照材料波阻抗软硬相间的排列顺序可以达到将透射波峰值和能量降低的最佳效果。利用一维差分程序模拟的分层介质中弹塑性应力波的传播规律表明，从硬材料到软材料的界面可以起到削弱应力波峰值和降低波的能量以及增加波形弥散的作用，其效果与界面两边材料的力学性能如波阻抗比、屈服强度比有关。通过对混凝土、黄土、沙土、泡沫混凝土等工程材料以及由它们构成的不同分层组合试件的SHPB冲击实验，在不同加载速率下，对各种材料或组合件的入射和透射应力峰值、能量进行了对比。结果显示，在一维应力或一维应变条件下，泡沫混凝土的抗冲击性能最好，黄土次之，混凝土和沙最差。多层组合试件的实验表明，分层材料中加入泡沫混凝土后其抗冲击吸能效果显著增加。采用国际通用动力学软件LSDYNA对SHPB实验进行数值模拟，计算结果和实验结果取得了一致，同时进一步研究了材料的本构对应力波传播的影响。以现行人防指挥工程为基准，采用1：4相似比，进行了几种不同分层防护结构的大比尺野外爆炸相似模拟试验，研究分层防护结构对爆炸波的衰减、阻尼和导向作用。试验分别采用平面装药加载和集团装药加载两种形式来模拟核爆和普通爆破航弹爆炸条件下防护结构所承受的冲击载荷。试验结果显示，平面装药加载下加入泡沫混凝土的多分层设置的人防工程对爆炸波峰值应力、应力冲量和震动加速度的衰减效果要明显优于分配层仅为沙的单层设置的人防工程。通过LSDYNA软件对集团装药加载下的模拟试验进行了数值模拟，进一步对现场爆炸试验进行了必要的补充分析，并采用数值模拟分析了相同冲量但强度和持续时间不同的载荷下，不同分层方式对人防结构的毁伤效应的影响。结果表明，分层总厚度相等的条件下，适当增加分层数目可以有效减小冲击载荷对结构的压、剪损伤和拉伸破坏，降低结构所受的冲击能量，尤其对于高强度、持续时间短的脉冲载荷，多分层防护结构的抗毁伤能力优势更为明显。更多还原

【Abstract】 At present, it forms a major project in the field of protection research how to improve the protection of layered protective structure, which is an important form of Civil Defense Construction in our country, against shock waves resulting from the explosion of some weapons, such as missiles, bombs and so on, under the background of high-tech war which is based mainly on attacking means of air raid. This dissertation emphasizes reforming the distribution layers of layered structure by making use of new energy-absorbing materials and transmission principles of stress waves in layered media, and further analyzing the transmission principles of explosive waves in construction and the destruction effect. As a project of great academic significance and application prospect, the research not only provides beneficial theory and practice so as to improve and optimize layered structure, but also can be used as reference while protection layers of both military and civil use are designed and popularized. The major contents of the dissertation are as following:By applying transmission and reflection principles of stress waves on the interface of layered media, it is derived mathematically that the peak value and energy of flexible waves change as wave impedance of material changes. It is also pointed out that the peak value and energy of transmission stress waves will reach an optimal decrease if different materials are arranged with the soft and hard wave impedance alternating with each other. As is showed by transmission principles of elastic and plastic stress waves in layered media, which is calculated by using finite difference method, the media interface of the soft and hard materials can exert effects on weakening the peak value and energy of stress waves, and strengthening the dispersion of stress waves. In addition, the effects relate to the mechanic performance of materials, such as ratio of wave resistance and yield stress, on both sides of the interface.With SHPB experiment on engineering materials such as concrete, soil, sand, foam and concrete, and different layered specimens made of them, comparing the stress peak value and energy of the input and transmission of different materials and combined specimens under different velocity loading, it is showed that foam concrete is the most impact-resistant, soil the second, and concrete and sand the worst. As also showed in the experiment of layered specimens, after a layered specimen is filled with foam concrete, the impact-resistance and energy-absorption will strengthen strikingly. Meanwhile, the dispersion of stress waves of layered materials strengthens as layers increase in number, which is more striking with high rate of strain. After numerical simulation of SHPB experiment via LSDYNA, international general dynamic software, the calculation result goes consistently with that of the experiment. Meanwhile, the experiment in this dissertation further studies effects the model of material constitution may exert on the peak value and energy of stress waves on transmission.Based on the actual Civil Defense Construction, applying the analogy ration of one to four, several analogy simulation experiments of large scale outdoor explosion with different layered forms protection construction are conducted, aiming at studying the weakening, resistance and directing effects of explosive waves resulting from layered protection construction. Applying plane and mass explosive load respectively, the experiment simulates the impact load on protection construction under the condition of nuclear and ordinary bomb explosion. It is showed that if a Civil Defense Construction with layered distribution in plane explosive load is inserted with foam concrete, it will be superior to which only with one distribution layer of sand in the weakening effect on the peak value stress, stress impulse and quake acceleration.After numerical simulation under mass explosive load via LSDYNA software, the explosion experiment on the spot is further supplemented and analyzed. In addition, applying numerical simulation, the experiment analyzes how different methods of layer forms affect the destruction of Civil Defense Construction with the same impulse intensity but different duration of load. The result shows that, under the condition of the same thickness of material, increasing the number of layers properly can weaken the press, the cutting damage and the destruction due to extension, and lower the impact energy on the construction effectively. In particular, multi-layered protection construction is rather striking in its advantage of destruction-resistance under high stress and low impulse load.更多还原