This layer has material const ants which govern the stiffness across it and has zerothickness.
该层的材料常数用劲度常数来描述，其层厚为零。
2
Considering that the crack thickness is usually very small, it can be taken as a'surface defect' with zerothickness.
根据裂纹的特点，可以把它近似为一个没有厚度的面缺陷，其作用由分布在裂纹面上的等效电流偶极子层代替。
3
Based on the study of features of sheet metal parts and ZeroThickness Hypothesis, a new mechanism of naming and identifying topological entities of a feature model is proposed in this paper.