【作者】 王堃；

【导师】 唐立强；

【作者基本信息】 哈尔滨工程大学 ， 固体力学， 2009， 硕士

【摘要】 随着科学技术的发展,在军事工程、建筑工程和航天航空材料工程提出许多有待于解决的复杂问题,需要从微观、细观以及宏观等不同层次上深入认识材料和结构的力学行为。在爆炸力学中,通常采用球形孔洞膨胀理论模型研究爆炸力学中一些问题。这是由于该模型具有对称性、简便明确,易于给出爆炸过程中物理量的分布,从而揭示材料的变形本质。采用球形孔洞膨胀模型研究爆炸力学问题,大多采用弹塑性模型,由于岩石中存在着随机分布的微裂纹,用损伤力学的方法研究材料在爆炸过程中的变形机理是十分重要的。认为材料的损伤区中仅存在径向应力σr,而球向应力σθ=0,只是损伤的极端情况。考虑到塑性区和弹性区对损伤变形的限制,从连续介质损伤力学的角度,深入研究爆炸过程中损伤区的变形状态,更具有理论意义和工程应用前景。在本文中,首先从连续介质损伤力学的热力学内变量理论出发,通过引入一个带损伤内变量的自由能函数,构造了损伤材料的本构方程。其次,在球对称条件下,推导出求解损伤区场量的控制方程和边界条件,再次通过数值计算得出球形孔洞膨胀的应力和位移分布,为进一步研究塑性—损伤—弹性爆炸模型提供参考依据。最后讨论了球形孔洞膨胀问题研究的发展趋势。本文从损伤力学角度,对球形孔洞膨胀问题进行较深层次的研究工作,这会使人们更深刻地认识材料(结构)的变形本质,为理论研究和工程应用奠定基础。更多还原

【Abstract】 With the development of science and technology, many complicated problems are presented in areas of military engineering, architectural engineering and material engineering of aerospace, it need to understand the mechanical behavior of material and structure deeply from different levels such as microscopic view and macroscopic view, In explosion mechanics, it usually adopts the spherical cavity expansion model to research some issues because of the symmetry of the model, it is very simple and specific, which can given the distribution of physical quantity conveniently, thus it reveal the essence of material deformation.Using the spherical cavity expansion model to research explosion problem, the elastic-plastic model is adopted mostly. It is important that using the damage mechanics method to research the deformation mechanism of material during the explosion process, because there are many microcracks distributing randomly in rocks. It is a extreme case that considered only radial stress is transferred and circumferential stress is zero. Considering the restriction of elastic region and plastic region, researching the deformation state of damage region deeply in explosion process, it have more theoretical significance and more application prospect on engineering.In this paper, first, starting form the thermodynamics internal variable theory of the continuous medium damage mechanics, construct the damage constitutive equations by introduced free energy function with damage internal variable. Secondly, this paper deduced governing equations and boundary conditions that based on the assumption of spherical symmetry for solving the field quantities of damage region, and get the distribution of displacement and the distribution of stress to provide the reference for researching the elastic-cracked-plastic model furtherly. At last, this paper discuss the research prospect of spherical cavity expansion problem.This paper research the spherical cavity expansion problem on deeper level, it makes people recognizes the deformation essence of material(or structure), and lay a foundation for theoretical research or engineering application.更多还原