考虑Z向应力复合材料层压板渐进失效计算方法

发布时间：2019-04-01 18:21

【摘要】：纤维增强复合材料因其高模量、高强度、可设计性好等优点使其在航空航天领域越来越广泛的应用。同时其应用的部位也从次承力构件向主承力构件过渡,飞机上的舱门、整流罩、安定面等次承力构件成为最初采用复合材料的部位,目前机翼、机身等主承力构件也广泛采用了复合材料。复合材料应用的不断推广使得复合材料中厚板和厚板也开始被广泛的应用起来。经典层压板理论将结构看做平面应力问题不适用于分析不能忽略Z向应力的厚板。如何有效地预测复合材料厚板其强度和损伤过程变得至关重要。本文总结叙述了国内外学者在复合材料构件的强度分析方面的研究,分析了现有的各种复合材料强度分析理论的优缺点。本文提出一种考虑Z向应力的复合材料层压板渐进失效计算方法。采用用户材料子程序UMAT,编写了材料属性程序。应用该程序分别对无缺口复合材料厚板、含孔复合材料厚板以及复合材料V型缺口梁各建立有限元模型。模型将厚度方向总体视为一层,无需额外划分单元,单元数量得到了极大的简化。应用模型对这三类复合材料厚板进行数值分析,进行了应力分析,计算了其极限强度,并预测了无缺口复合材料厚板和含孔复合材料厚板的损伤扩展过程。模型厚度方向虽然只有一层单元,仍然能算出复合材料厚板每一单层的应力场。本文在简化模型,极大提高计算效率的基础上,准确的分析了每一单层的应力场,提高了厚板强度预测的精度。为进一步开展对各种不同铺层的中厚度尺寸试验件结构的强度预测奠定了基础,对深入了解其损伤扩展过程具有重要的参考价值。
[Abstract]:Fiber reinforced composites are more and more widely used in aeronautics and astronautics due to their high modulus, high strength and good design property. At the same time, the position of its application is also transitioned from the secondary bearing component to the main bearing component. The cabin doors, fairing cover, stabilizing surface and other secondary bearing components on the aircraft become the parts where the composite material was initially used, at present, the wings, Composite materials are also widely used in the main bearing components such as fuselage. The continuous application of composite materials makes the composite plate and plate become more and more widely used. The classical laminated plate theory considers the structure as a plane stress problem which is not suitable for the analysis of thick plates which cannot ignore Z-direction stress. How to predict the strength and damage process of composite thick plate is very important. In this paper, the domestic and foreign scholars' research on the strength analysis of composite members is summarized, and the advantages and disadvantages of the existing theories of strength analysis of composite materials are analyzed. A method for calculating progressive failure of composite laminate considering Z-direction stress is presented in this paper. The user material subroutine UMAT, is used to write the material attribute program. The finite element models of non-notched composite thick plate, perforated composite thick plate and composite V-notched beam are established by using the program. The model regards the thickness direction as a whole as a single layer and the number of elements is greatly simplified without the need for additional dividing elements. The model is applied to the numerical analysis of these three types of composite thick plates, the stress analysis is carried out, the ultimate strength is calculated, and the damage propagation process of the non-notched thick composite plates and the composite thick plates with holes is predicted. Although there is only one layer element in the thickness direction of the model, the stress field of each single layer of composite thick plate can still be calculated. On the basis of simplifying the model and greatly improving the calculation efficiency, the stress field of each single layer is analyzed accurately in this paper, and the precision of strength prediction of thick plate is improved. It lays a foundation for the strength prediction of the structure of different layers with medium thickness and size, and has important reference value for further understanding the damage propagation process of the specimens.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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