【作者】 黄西成；

【导师】 朱建士； 陈裕泽；

【作者基本信息】 中国工程物理研究院 ， 工程力学， 2010， 博士

【摘要】 在武器工程结构设计中,最为常见的应用是轴对称结构的柱壳和球壳,这是两类最为典型的“高能效、低能耗”结构。对这两种结构在爆炸作用下的变形与破坏研究,一直以来在学术界和工程界就有浓厚的兴趣。在科学研究方面,由于壳体的动态破坏与材料在强动载荷下的变形和破坏机理密切相关,这些课题一直是固体力学中的一个重要研究领域,并且关联到材料力学、断裂力学、固体物理及爆炸力学等多种学科之间的相互交叉和渗透。因此,关于柱壳和球壳在爆炸作用下变形与破坏的研究,既具有重要的理论研究价值,又具有十分重要的工程意义。在这些研究中,最关注的是结构破坏,因为在大多数情况下,武器结构在作战过程或放能过程中,结构的损伤与破坏是最重要的过程之一,而且这种破坏过程直接关系到武器效应的发挥。关注这些过程的细节,是现代武器设计中最重要的环节之一。为了较全面认识爆炸作用下柱壳和球壳的破坏模式,加深理解结构动态破坏的具体细节,为物理设计和工程设计提供较为清晰的物理图像,应深入研究内爆与外爆加载下壳体的力学状态及破坏模式。围绕上述目的,本论文开展了如下几方面的研究工作：固体中的冲击波传播、内爆加载下柱壳应力状态与破坏模式、外爆加载下柱壳应力状态与破坏模式、内爆加载下球壳应力状态与破坏模式、外爆加载下球壳应力状态与破坏模以及两个基本实验以及物态方程与本构关系的相关性。①固体冲击压缩研究中的若干问题。基于连续介质力学基本理论,讨论了冲击动力学中的若干问题,如流体动力学近似、状态方程与本构方程的关联与本质、一维应力实验与一维应变实验、综合性实验与基础性实验等。②内爆加载下柱壳应力状态与破坏模式。分析了平面应变加载问题,为简化分析起见,先采用静力分析,并忽略体力,寻找柱壳内的应力和应变的分布规律,为破坏模式的定性分析提供理论基础。之后分析滑移爆轰下柱壳内的应力状态以及层裂发生的位置。采用数值模拟,分析了滑移内爆作用下柱壳向心汇聚运动中的应力状态以及破坏模式。③外爆加载下柱壳应力状态与破坏模式。采用数值模拟方法,分析了外爆加载下柱壳早期应力波传播、应力状态以及破坏模式；采用解析法分析了柱壳膨胀过程的应力状态以及破坏模式；介绍了柱壳膨胀的Mott统计断裂理论；对Gurson模型进行了详细的推导,给出了屈服函数、本构关系以及塑性应变的计算方法,以及Gurson模型中材料参数的识别方法。基于这些理论,将Gurson模型编写子程序并嵌入到HKS/Abaqus软件中,分析了柱壳膨胀断裂过程中的剪切型破坏。分析了外爆加载下厚壁柱壳的破坏模式。④内爆加载下球壳应力状态与破坏模式。进行了外压作用下球壳的弹性应力状态的静力分析,并对柱壳和球壳的应力状态进行了比较,尽管是静力学分析,但对于壳体后期的运动分析是有帮助的；之后进行了外压作用下球壳和柱壳的动力学分析比较,给出了两种典型结构在冲击作用下的应力状态比较；对内爆加载下球壳塌陷过程进行了理论分析,比较了材料参数和压力参数等对塌陷过程的影响；对外表面弱冲击和强冲击加载下球壳应力状态进行了数值分析,并对内爆加载下的球壳与一维应变平板接触爆炸加载以及柱壳内聚爆炸进行了比较。最后开展了内爆加载下球壳层裂的数值模拟。⑤外爆加载下球壳应力状态与破坏模。从理论方面分析外爆加载下球壳中的弹塑性球面应力波传播,并与一维应变波传播进行了比较；采用解析法分析了球壳膨胀过程中的应力状态以及失效模式；给出了球壳的膨胀破坏半径的近似分析以及参数的影响；给出了内部爆炸作用下球壳破裂时间的理论分析。采用数值分析法模拟了外爆加载下2169钢厚壁球的层裂破坏。更多还原

【Abstract】 In the weapon engineering design, the most common applications are the axisymmetric structures:cylindrical and spherical shells. These are typical structures of more energy efficient and less energy consumption. The investigation into the deformation and fracture of such structures imparts great interest among academic circles and engineering field. In scientific studies, the dynamic fractures of shells are closely bound up with deformation and fracture of materials under dynamic loading. These research subjects have become an important area of research in solid mechanics, and related with material strength, fracture mechanics, solid physics and explosion mechanics. Thus the studies on the deformation and fracture of cylindrical and spherical shells are of great worth of theoretical study, and also of great importance of engineering applications. In these studies, the structural fracture attract the most attention. This is because in most cases the structural damage and fracture are most important processes in attacking or releasing energy, and these processes concerns weapons effects. The careful attention to the detail process is the key node in modern weapon design.In order to understand comprehensively the failure modes of cylinder and sphere subjected to blasting loading, recognize thoroughly the details in the structural fractures, provide physics design and engineering design with clear physics image, the mechanical states and failure modes of shells subjected to implosive and explosive loading should be investigated deeply. For these purposes the following studies are performed in this dissertation: 1) shock wave propagation in solid,2)the stress state and failure modes of cylindrical shell subjected to implosive loading,3)the stress states and failure modes of cylindrical shell subjected to explosive loading,4)the stress states and failure modes of spherical shell subjected to implosive loading,5)the stress states and failure modes of spherical shell subjected to explosive loading,6) the two basic experiments and correlation between EOS and constitutive relations.1) Some problems in studies of shock compression of solid. On the base of the fundamental theory in continuum mechanics, some problems in studies of shock compression of solid are discussed, such as hydrodynanic approximation, relationship between equation of state and constitutive equation, and their essential distinction, one-dimensional stress and one-dimensional strain experiments, integrated and basic experiments.2) The stress state and failure modes of cylindrical shell subjected to implosive loading. Plan strain problem is analyzed. For simplification the static analysis, not considering body force, is performed. The static analysis can provide the distributions of stress and strain, and can also provide the theoretical principle for qualitative analysis of failure modes. Then the stress state and spall fracture of cylinder subjected to sliding detonation loadings are analyzed. By means of numerical modeling, the stress state and fracture modes of collapsing cylinder subjected to sliding detonation loadings are simulated.3) The stress state and failure modes of cylindrical shell subjected to explosive loading. The stress wave propagation, stress state and fracture modes of cylinder at early stage are analyzed using numerical modeling. The stress state and fracture modes of expanding cylinder are studied by analytical method. The Mott statistical fracture theory for cylinders is introduced. The Gurson model is derived in detail. The yield function, constitutive equation and plastic strain formula are presented. The approach of Gurson parameter identification is given. The user subroutine of Gurson model is embedded in HKS/Abaqus. By Gurson model, the shear fracture mode of expanding cylinder is simulated. The fracture modes of think-walled cylinder are analyzed.4) The stress state and failure modes of spherical shell subjected to implosive loading. The static analysis of elastic stress state of sphere under external pressure is performed. The comparison between stress state of cylinder and that of sphere is made. Although the analysis is static, yet it is helpful for analysis of shell at later phase. Then, the dynamic analysis and comparison are given. The collapsing process of spherical shell under implosive loading is analyzed, and the parametric influences, such as material parameter, pressure parameter, are studied. The stress states in sphere under weak and strong shocks are analyzed. The compression between one dimensional strain, cylinder and sphere are made. At last, the spalling of sphere subjected to implosive loadings are modeled numerically.5) The stress states and failure modes of spherical shell subjected to explosive loading. The spherical stress wave propagation in sphere under explosive loading is analyzed theoretically, and also compared with one dimensional strain wave. The failure modes are studied. The fracture radius and fracture time of sphere are given. The spalling of think-walled sphere made by SS21-6-9 subjected to internal explosion is modeled.更多还原