请教ABAQUS对单元特征长度的定义

mantuoluocat

在建模中遇到单元的特征长度的问题。请问ABAQUS中单元的特征长度是如何定义的啊？我找了两个版本的manual对特征长度的介绍，还是不理解。请各位大侠帮忙啊。谢谢。—ßR‡ KµÁØforums.simwe.com
附：定义一：The definition of the characteristic length is based on the element geometry: for beams and trusses we use the integration point length; for shell and planar elements we use the square root of the integration point area; for solid elements we use the cube root of the integration point volume. This definition of the characteristic length is used because the direction in which fracture occurs is not known in advance. Therefore, elements with large aspect ratios will have rather different behavior depending on the direction in which they crack: some mesh sensitivity remains because of this effect, and elements that have aspect ratios close to unity are recommended.—ßR‡ KµÁØforums.simwe.com
定义二：—ßR‡ KµÁØforums.simwe.com
The definition of the characteristic length depends on the element geometry and formulation: it is a typical length of a line across an element for a first-order element; it is half of the same typical length for a second-order element. For beams and trusses it is a characteristic length along the element axis. For membranes and shells it is a characteristic length in the reference surface. For axisymmetric elements it is a characteristic length in the r–z plane only. For cohesive elements it is equal to the constitutive thickness. This definition of the characteristic length is used because the direction in which fracture occurs is not known in advance. Therefore, elements with large aspect ratios will have rather different behavior depending on the direction in which they crack: some mesh sensitivity remains because of this effect, and elements that have aspect ratios close to unity are recommended.—ßR‡ KµÁØforums.simwe.com