热环境中旋转运动功能梯度圆板的强非线性固有振动

研究热环境中旋转运动功能梯度圆板的非线性固有振动问题．针对金属－陶瓷功能梯度圆板，考虑几何非线性、材料物理属性参数随温度变化以及材料组分沿厚度方向按幂律分布的情况，应用哈密顿原理推得热环境中旋转运动功能梯度圆板的非线性振动微分方程．考虑周边夹支边界条件，利用伽辽金法得到了横向非线性固有振动方程，并确定了静载荷引起的静挠度．用改进的多尺度法求解强非线性方程，得出非线性固有频率表达式．通过算例，分析了旋转运动功能梯度圆板固有频率随转速、温度等参量的变化情况．结果表明，非线性固有频率随金属含量的增加而降低；随转速和圆板厚度的增大而升高；随功能梯度圆板表面温度的升高而降低．

EXPERIMENTAL INVESTIGATION AND NUMERICAL SIMULATION OF THE STRESS-STRAIN BEHAVIOR OF 2D WEAVE CERAMIC MATRIZ COMPOSITES

stress-strain behavior of 2D weave ceramic matrix composite is studied by experimental and theoretical method. 2D weave structure is simplified as crossply structure and fiber bundle undulation structure; Basing on matrix strength stochastic distributing theory and fiber failure stochastic distributing theory, stress-strain behavior and tangent tensile modulus related to applied load of unidirectional composite (0°ply) are obtained. Utilize the relationship of between crossply and unidirectional ceramic matrix composite stress-strain behavior, when their material is the same, one can obtain stress-strain behavior of crossply ceramic matrix composite. A two-dimensional analytical method is presented for fiber bundle undulation structure. Introduce composite strength model, the undulation structure is divided into sub-elements, in the meantime including linear behavior and non-linear behavior of sub-elements owing to off-axial loading. The failure analysis is carried out considering the failure of different sub-elements in fiber bundle undulation structure. Moreover，stress-strain behavior of undulation structure is obtained. Combine crossply and undulation structure’s stress-strain behavior, stress-strain behavior 2D weave ceramic matrix composite is gained; and theoretical result is well agreed with experimental result.