【作者】 张龙；

【导师】 郭力；

【作者基本信息】 东南大学 ， 工程力学， 2015， 硕士

【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。更多还原

【Abstract】 Laminated composite plates have been widely used in aerospace, automobile and other branches of engineering due to their superior thermal and mechanical properties. However, Large temperature changes generally occur in the fabrication, processing as well as service exposure of laminated composite plates. Due to the mismatch in material properties between adjacent layers, the temperature changes will result in internal thermal stresses during fabrication cooling down as well as service thermal loads. These stresses may be large enough to induce large deformation and even cause fiber fracture, debonding arid matrix failure of laminated structures. Thus, the accurate prediction of the thermal stress distributions is a key issue for laminated composite plates exposed to a thermal environment.Firstly, the research status of laminated composite plates theories is reviewed in detail and the advantages and disadvantages of various theories are compared and summarized. A research work called global-local higher-order shear deformation theory, can accurately predict the transverse shear stress components of laminated composite plates subjected to mechanical loads without any post processing. This theory has achieved a good balance on the efficiency and precision. Therefore, this paper will be based on the global-local higher-order shear deformation theory.Secondly, the global-local higher-order shear deformation theory is deduced in detail. By employing displacement continuity conditions at interfaces, transverse shear stress continuity conditions and free surface stress boundary conditions, the number of the displacement variables is reduced to 11. The equilibrium equations are obtained by using the principle of virtual displacements, and results are computed by using Navy’s technique, aiming at establishing the theoretical foundation for the ensuing chapters.The temperature field and the three-dimensional linear elastic solutions have been summarized firstly. With applying Navier’s technique, analytical solutions in terms of a double trigonometric series for simply supported laminated plates subjected to thermal loads are presented. The thermal analysis of 0° 90°/ 0°and 0°/core/0° simply supported laminated plates under thermal load with constant, linear and nonlinear temperature profile by solving the heat conduction equation are analyzed. Comparison of the present results with those of the three-dimensional theory of elasticity and the available plate theories confirms the efficiency and accuracy of the proposed theory. Two different profiles of temperature have been compared on laminated composite plates:(1) the linear one; (2) the nonlinear profile obtained by solving the heat conduction problem. Results reveal that a wrong temperature profile gives an erroneous thermal load for the analysis of laminated composite plates.Analytical solutions in terms of a double trigonometric series for simply supported laminated plates subjected to thermo-mechanical loads are presented and the three-dimensional linear elastic solutions of laminated composite plates subjected to thermo-mechanical loads are summarized.The mechanical and thermal-mechanical analysis of 0° 90°/0 °simply supported laminated plates are analyzed. Comparison of the present results with those of the three-dimensional theory of elasticity and the Abaqus finite element solution confirms the efficiency and accuracy of the proposed theory.Finally, the fiber orientations and stacking sequence of laminated composite plate are optimum designed to reduce the transverse shear stress. The Optimization design is divided into two steps:The first step aims to optimize the fiber orientation,and designs 6 kinds of typical fiber orientations; The second step designs eight different stacking sequence scheme on the basis of the first step, aiming to optimize the stacking sequence.更多还原