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对季节性积雪的力学性能的研究,主要目的是应用于雪崩的释放和雪崩的控制。但也应用于一些不甚重要的问题,如运载工具在雪上的运动,雪的清除,雪上建筑等。这项研究工作主要需要:①本构方程,即应力张量同运动之间的关系,②断裂判据,它限制本构方程的有效范围。二者都可以根据连续统理论和结构理论的观点来得到。借助现代连续统理论,可以研究雪的非线性特性和对应力及应变历史的强烈依赖关系。当引进热力学量时,可以更深入地了解变形和断裂过程。大的初始变形率可引起小的耗散、弹性行为和脆性断裂,而当耗散机制可以发展时,会发生塑性断裂。结构理论的优点在于可从物理上直接深入了解变形机制,其缺点则是只能考虑宏观地作用于雪样上的简单应力状态。详细叙述了不同的方法:对于低密度雪,链(一系列承受应力的冰粒)的概念或颈部增长模型(考虑冰粒间的键中的应力集中);对于高密度雪,孔隙崩坍模型(雪被理想化为含有空气穴的材料)。应用结构本构方程来计算雪的应力波。所记录的声发射指出了晶粒间的键的断裂,这些声发射可用来构造本构方程。结构破坏理论以串联的微元来模拟脆性断裂,其中最弱的链环引起整个物体的断裂;而并联的微元模拟塑性断裂,其中一个微元的断裂仅导致应力的重新分布,并且仅在载荷增加到充分?
The main purpose of the research on the mechanical properties of seasonal snow is to apply avalanche release and avalanche control. But also applies to some less important issues, such as vehicle movement in the snow, snow removal, snow construction. The main work of this research need: (1) constitutive equation, the relationship between stress tensor and motion, (2) fracture criterion, which limits the effective range of the constitutive equation. Both can be obtained from the perspective of continuum theory and structural theory. With modern continuum theory, one can study the nonlinear behavior of snow and its strong dependence on the history of stress and strain. When thermodynamic quantities are introduced, the deformation and fracture processes can be better understood. Large initial deformation rates can cause small dissipation, elastic behavior, and brittle fracture, and plastic fracture occurs when the dissipation mechanism can develop. The advantage of structure theory is that it can directly understand the deformation mechanism directly from physics. The disadvantage is that it can only consider the simple stress state that acts macroscopically on snow samples. Different methods are described in detail: the concept of a low-density snow chain (a series of stress-bearing ice particles) or a model of neck growth (taking into account stress concentrations in the bonds between ice particles); for high-density snow and void collapse models (Snow is idealized as a material containing air pockets). The constitutive equation of structure is used to calculate the stress wave of snow. The recorded acoustic emission indicates the breaking of the bonds between the grains that can be used to construct the constitutive equation. The theory of structural failure simulates brittle fractures in series of elements, where the weakest linkages cause the entire object to fracture; and the parallel micromorphic plastic fractures, in which fracture of one element leads to only a redistribution of stress, Load increased to full?