含分层损伤复合材料等三角形格栅加筋板的起裂和扩展过程研究

Study on delamination onset and growth process for composite advanced isogrid stiffened structures(AGS)

对在压缩载荷下先进复合材料等三角形格栅加筋板结构(AGS)后屈曲阶段的分层起裂和扩展过程进行了研究。基于一阶剪切变形理论和Von-Karman几何非线性关系,提出了AGS结构后屈曲有限元分析模型;基于总能量释放率准则,并利用虚裂纹闭合法(VCCT)及自适应网格的生成和移动技术分析了分层损伤的扩展过程,在分析过程中考虑了分层前缘的接触效应。并通过典型算例,讨论了不同的初始分层尺寸、肋骨刚度对等三角形格栅加筋板结构的分层起裂和扩展过程的影响,通过与具有相同几何尺度的正交格栅加筋板结构的比较,说明等三角形格栅加筋板结构具有较高的抗分层能力。本文方法和所得结论对AGS结构的承载能力预测和设计将具有参考价值。

A numerical method was developed to study the delamination onset and growth characteristics during the post-buckling process for the delaminated composite advanced isogrid stiffened plates subjected to a uniform axial compressive load. A finite element post-buckling analysis model was established based on the first-order shear deformation theory in conjunction with Von- Karman geometrically nonlinear theory. The total energy release rate criterion combined with the virtual crack closure technique and the self-adaptive grid moving technology were used to analyze the delamination growth process, considering the contact effect of front contours of the delamination. By some numerical examples, the effects of radius of delamination and rib stiffness upon the delamination growth process were discussed. Comparing the results between the isogrid and the orthogrid stiffened plates with the same dimensions shows that the isogrid stiffened plate has good resistance ability against delamination onset and growth. The analysis method and conclusions provided in the paper would be valuable to estimate the load capability and optimal design for composite advanced grid stiffened structures.