Volume 37, Number 4, August 2019
|Page(s)||730 - 736|
|Published online||23 September 2019|
Damage Analysis and Experimental Study of Composite Structures with Initial Delamination
College of Shipbuilding Engineering, Harbin Engineering University, Harbin 150001, China
Composite laminates are prone to delamination during hot pressing and cooling, this delamination is one of the most important defects that affect the properties of composite structures, the formation and propagation of delamination in composite materials can significantly reduce the structural strength of composite materials and even lead to catastrophic failure. In this paper, the two parameters of the initial stratified position and the initial stratified diameter are selected to research the effects of these two parameters on the mechanical properties of composite laminates through numerical simulation and experiment, and concludes that the influence of initial delamination along the thickness direction on the average compression modulus and strain of the linear segment is small; the influence of delamination on the ultimate bearing capacity increases with the decrease of the distance between the delamination and the center plane. When the diameter of the delamination is in the range of 8%~20% of the effective area(18~44 mm), the influence on the average compression modulus, ultimate bearing capacity and strain of the linear segment is not obvious. When the diameter is increased to 27% of the effective length(60 mm), the above properties have changed greatly. And then, this paper introduces the bilinear controlled cohesive elements into the progressive failure method to calculate the ultimate load capacity of composite laminates, and demonstrate the accuracy of the simulation method by experiments.
复合材料层合板在热压成型以及冷却过程中容易出现分层缺陷，分层缺陷是影响复合材料性能最主要的缺陷形式之一，其在复合材料中的产生和扩展都会显著降低复合材料的结构强度甚至引发灾难性的破坏，所以复合材料的分层缺陷对于结构的可靠性有着十分重要的影响。以初始分层位置以及初始分层直径2个参数作为研究对象设计实验，通过数值模拟和试验得到两者对于复合材料层合板力学性能的影响规律，并得出以下结论：初始分层沿厚度方向位置对线性段平均压缩模量以及应变的影响较小，分层越接近中心面，对极限承载能力影响越大；当缺陷直径在有效作用区长度的8%~20%（18~44 mm）范围内时，对层合板线性段平均压缩模量、极限承载能力以及应变的影响变化不明显，当直径提升到有效作用区长度的27%（60 mm）时，以上性能均出现较大变化。另外，将双线性内聚力单元引入渐进失效方法计算层合板极限承载能力，通过试验结果与数值模拟的对比验证了算法的准确性。
Key words: initial delamination / compositelaminates / cohesive zone model / progressive damage / structural strength / numerical simulation / experiment / ultimate bearing capacity
关键字 : 初始分层 / 复合材料 / 内聚力模型 / 渐进失效
© 2019 Journal of Northwestern Polytechnical University. All rights reserved.
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