热—力作用下复合材料层合板的响应分析

发布时间：2018-11-26 14:22

【摘要】：复合材料由于其优良的力学物理性能已经广泛被应用于航空航天、船舶工程、建筑工程、车辆制造工业和机械工程等不同领域。然而在复合材料制造、加工和使用过程中往往会伴随有剧烈的温度变化,由于层合板层间材料属性的不同,层合板内部会产生显著的温度应力。这些温度应力会大到足以使结构产生过大的变形,甚至导致层合板结构纤维的断裂、剥离和基体的破坏。因此,为了最大限度的保证复合材料层合结构的安全可靠,准确预测热荷载作用下复合材料层合板中的应力分布情况是一个重要的科学问题。本文首先对层合板理论研究现状进行了详细综述,总结了各种理论的优缺点。其中整体-局部高阶剪切变形理论,对于复合材料层合板,此方法可以直接应用本构方程计算面内应力和横向剪切应力。该理论在效率和精度上取得了很好的平衡。因此,本文的工作基于此理论展开。其次详细推导了整体-局部高阶剪切变形理论,在整体-局部理论初始位移模式的基础上引入层问位移连续条件、横向剪切应力连续条件和自由面应力边界条件,得到仅含有11个整体位移未知量的整体-局部高阶剪切变形最终位移模式,为分析层合板在热荷载、力荷载、热-力荷载下的响应分析奠定了理论基础。针对热荷载作用下的层合板及夹层板结构响应分析,首先对层合板温度场和热荷载作用下三维线弹性解进行了整理和总结。应用Navier's双极数展开方法给出了四边简支层合板的解析解。对三层0。/90。/0。四边简支层合板和0。/core/0°四边简支层合板,分别计算了沿厚度均布热荷载、梯度分布热荷载、热传导求解分布热荷载作用下的响应,与其他学者公开发表的结果进行详细的对比,结果表明整体-局部高阶剪切变性理论对求解复合材料层合板热响应分析问题具有明显的优势。同时对比了热传导方程解出的温度场与线性假定温度场作用下层合板的热响应,结果显示一个不当的温度场的假定会导致层合板热响应的较大误差产生。在热荷载作用的基础上,给出热-力荷载作用下四边简支层合板的解析解,并对力荷载及热-力荷载作用下层合板三维线弹性解进行总结。数值算例重点对三层0。/90。/0。四边简支层合板在力荷载和热-力荷载作用下的典型算例进行研究,与其他学者公开发表的文献结果以及Abaqus有限元解进行了对比,验证了整体-局部高阶剪切变性理论求解复合材料层合板热-力荷载下响应分析问题的适用性和精确性。最后通过采取改变层合板铺层的方向、顺序的优化思路,对层合板进行铺层优化设计,达到减小层间应力,提高复合材料抵抗分层能力的目的。优化设计分为两步：第一步对铺设角度进行优化,设计了6种典型的铺设角度组合：第二步对铺设顺序进行优化,在第一步找到的较优铺设角度组合基础上,设计了新的8种不同铺层顺序方案。
[Abstract]:Composite materials have been widely used in aerospace, ship engineering, building engineering, vehicle manufacturing industry and mechanical engineering due to their excellent mechanical and physical properties. However, in the process of manufacturing, processing and using of composite materials, there are often severe temperature changes. Due to the different properties of laminated materials, significant temperature stress will occur in laminated plates. These thermal stresses will be large enough to cause excessive deformation of the structure, and even lead to the fracture, stripping and matrix destruction of laminated structure fibers. Therefore, in order to ensure the safety and reliability of composite laminates to the maximum extent, it is an important scientific problem to accurately predict the stress distribution in composite laminates under thermal loading. In this paper, the current situation of laminated plate theory is reviewed in detail, and the advantages and disadvantages of these theories are summarized. For laminated composite plates, the in-plane stress and transverse shear stress can be directly calculated by the constitutive equation. The theory achieves a good balance in efficiency and precision. Therefore, the work of this paper is based on this theory. Secondly, the global-local high-order shear deformation theory is derived in detail. Based on the initial displacement model of the global-local theory, the continuous condition of layered displacement, the continuous condition of transverse shear stress and the boundary condition of free surface stress are introduced. Finally, the final displacement model of global and local high-order shear deformation containing only 11 global displacement unknowns is obtained, which lays a theoretical foundation for the analysis of laminated plates under thermal load, force load and thermal-force load. According to the response analysis of laminated plates and sandwich plates under thermal load, the temperature field of laminated plates and the three-dimensional linear elastic solutions under thermal load are summarized. The analytical solution of simply supported laminated plates with four edges is given by using Navier's 's bipolar expansion method. Yeah, three layers, 0.r90.0.0.0.0.0.0.0.0.0.0. Four side simply supported laminated plates and 0./core/0 掳four side simply supported laminated plates are calculated, respectively. The thermal loads are distributed along the thickness, the thermal loads are distributed gradient, and the responses under the distributed thermal loads are solved by heat conduction. Compared with the published results of other scholars, the results show that the theory of global and local high order shear denaturation has obvious advantages in solving the thermal response analysis of composite laminated plates. At the same time, the thermal response of the laminated plate under the action of the temperature field calculated by the heat conduction equation is compared with that of the linear assumed temperature field. The results show that the assumption of an improper temperature field will lead to a large error in the thermal response of the laminated plate. Based on the effect of thermal load, the analytical solution of simply supported laminated plates with four edges under the action of thermal-force load is given, and the three-dimensional linear elastic solution of the laminated plate under the action of force load and thermal-force load is summarized. Numerical examples focus on the three layers of 0. / 90. The typical numerical examples of simply supported laminated plates with four edges subjected to force and thermal-mechanical loads are studied and compared with the results published by other scholars and the Abaqus finite element solution. The applicability and accuracy of the global-local high-order shear denaturation theory for the response analysis of composite laminated plates under thermal-mechanical loads are verified. Finally, by changing the direction and sequence of laminated laminates, the optimal design of laminated plates is carried out to reduce the interlaminar stress and improve the anti-delamination ability of composite materials. The optimization design is divided into two steps: the first step is to optimize the laying angle, and six typical laying angle combinations are designed; the second step is to optimize the laying sequence, based on the better laying angle combination found in the first step. Eight new schemes of different layering sequence are designed.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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