隔板增强复合材料泡沫夹芯梁剪切性能研究

发布时间：2018-03-16 07:32

本文选题：复合材料夹芯梁　切入点：泡沫夹芯　出处：《南京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：泡沫夹芯复合材料结构具有质量轻、强度大、刚度大等显著优点,目前已经应用于航天航空、船舶等领域。本文所研究的隔板增强泡沫-复合材料夹芯梁是由常温共固化成型的夹芯板切割而成,以玻璃纤维复合材料作为面层和隔板,以PU泡沫为芯材；隔板增强型式有三种,分别为横隔板增强、纵向隔板增强以及双向隔板增强。在横向剪切荷载作用下,泡沫夹芯梁的主要破坏模式为芯材剪切破坏和界面剥离破坏,采用隔板增强方法,将隔板、泡沫夹芯和面层形成有机整体,有利于夹芯梁的界面构造。本文通过试验研究、理论分析和数值模拟,对隔板增强复合材料泡沫夹芯梁三点弯作用下的受剪性能进行了研究,主要研究内容及结论如下：(1)通过三点弯剪切试验,测定泡沫密度为150kg/m3的横隔板增强夹芯梁的剪切性能,通过与无增强夹芯梁进行对比,分析横隔板增强对夹芯梁抗剪性能的影响,以及不同横隔板间距的不同影响效果。(2)在泡沫密度为150kg/m3的横隔板增强夹芯梁的剪切性能研究基础上,选择两种有效的横隔板间距,进一步测量泡沫密度为60kg/m3的横隔板增强夹芯梁的剪切性能,并与无增强夹芯梁进行对比,详细分析横隔板增强对夹芯梁抗剪性能的增强效果及局限；同时,鉴于横向隔板增强方式在抗剪性能上的局限,对另外两种不同方向的隔板增强：纵向与双向隔板增强的夹芯梁进行三点弯试验。(3)基于Hoff理论分析夹芯结构,采用Timoshenko梁理论,考虑弯曲变形和剪切变形的共同影响,通过几何法和能量法,推导横隔板增强梁在线弹性段的挠度和刚度；同时,采用三种不同的破坏准则或者破坏模式的对应公式得到极限承载力的简化计算公式,对横隔板及纵向隔板增强的夹芯梁进行承载力分析,运用UNSYS有限元建模,将其结果与理论解及试验值进行比较分析。
[Abstract]:The foam sandwich composite structure has many advantages, such as light weight, high strength, high stiffness and so on. It has been used in aerospace and aviation at present. In the field of ship and so on. The membrane reinforced foam-composite sandwich beam studied in this paper is cut from the sandwich board of common solidification molding at room temperature. The glass fiber composite material is used as the surface layer and the partition board, and the pu foam is used as the core material. There are three types of strengthening type of diaphragm, which are transverse diaphragm strengthening, longitudinal diaphragm strengthening and bidirectional diaphragm strengthening. Under transverse shear load, the main failure modes of foam sandwich beams are core shear failure and interface stripping failure. By using the method of partition reinforcement, the partition, foam sandwich and surface layer are formed as an organic whole, which is beneficial to the interface structure of the sandwich beam. In this paper, by means of experimental study, theoretical analysis and numerical simulation, The shear behavior of composite foam sandwich beam reinforced by diaphragm under three point bending is studied. The main contents and conclusions are as follows: 1) the shear behavior of sandwich beam reinforced by transverse partition with foam density of 150 kg / m ~ 3 is measured by three-point bending shear test. By comparing with the non-reinforced sandwich beam, the influence of transverse diaphragm reinforcement on the shear resistance of sandwich beam and the different effects of different transverse diaphragm spacing on the shear behavior of sandwich beam reinforced by transverse diaphragm with foam density of 150 kg / m ~ 3 were analyzed. Two effective transverse spacers were selected to further measure the shear behavior of sandwich beams with foam density of 60 kg / m ~ 3, and compared with those of non-reinforced sandwich beams. This paper analyzes in detail the enhancement effect and limitation of transverse diaphragm reinforcement to the shear resistance of sandwich beam, and in view of the limitation of shear performance of transverse diaphragm reinforcement, Three point bending tests are carried out on the sandwich beams reinforced by longitudinal and bidirectional separators in two different directions. Based on the Hoff theory, the sandwich structure is analyzed. The Timoshenko beam theory is adopted to consider the joint effects of bending deformation and shear deformation. Through geometric method and energy method, the deflection and stiffness of the elastic section of the beam strengthened by transverse diaphragm are deduced, and the simplified formula of ultimate bearing capacity is obtained by using three different failure criteria or the corresponding formula of failure mode. The bearing capacity of sandwich beams reinforced by transverse and longitudinal separators is analyzed. The results are compared with theoretical solutions and experimental values by using UNSYS finite element method.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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