Study on Optimum Design of an Intelligent Composite Plate with Heat Resistance

(1)通过压电热弹性分析和数值模拟，建立了由两层压电层粘结的耐热结构层构成的复合板的热弹性位移智能控制系统。当未知加热温度作用于底部自由面时，从中间压电层上感应的电势分布推断出作用于顶部压电层的瞬时电势分布，从而控制底部表面的弹性位移。(2)在由多个压电层粘结的具有热阻的结构层组成的复合板中，论证了一个优化设计问题。当通过对每个压电层施加电势来控制底部自由表面上的热致弹性位移时，每个压电层的厚度是在应力约束下确定的，从而使所施加的最大电势最小。采用基于拟牛顿法的神经网络，得到了合理的设计结果。提出了一种基于平面应力条件的简便求解方法，并对压电圆板的热弹性问题进行了分析。基于平面应力解的数值结果与由先前导出的精确三维解得到的结果吻合较好。平面应力公式比三维公式简单得多。将平面应力解应用于多层复合板，认为可以大大减少数值计算所需的执行时间，从而提高智能函数的响应。

(1) In a composite plate constructed of a structural layer with heat resistance onto which two piezoceramic layers are bonded, an intelligent system of controlling a thermoelsatic displacement is developed by means of piezothermoelastic analyses and numerical simulations. When a transient unknown heating temperature acts on the bottom free surface, it is inferred from the electric potential distribution induced on the middle piezoceramic layer, and then a transient electric potential distribution applied to the top piezoceramic layer which controls the elastic displacement on the bottom surface is determined.(2) In a composite plate consisting of a structural layer with heat resistance onto which multiple piezoceramic layers are bonded, an optimum design problem is demonstrated. When the thermally induced elastic displacement on the bottom free surface is controlled by applying an electric potential to every piezoceramic layer, the thickness of each piezoceramic layer is determined subject to stress constraints so that the maximum applied electric potential is minimized. Employing neural networks based on the quasi-Newton method, appropriate design results are obtained. Re-optimum design of the multi-layered composite plate is also demonstrated by relaxing the stress constrains.(3) A convenient solution technique based on the plane-stress conditions is proposed and then thermoelastic problems of piezoceramic circular plates are analyzed. Numerical results based on the plane-stress solution are in good agreement with those derived from a previously derived exact three-dimensional solution. The Plane-stress formulations are much simpler than the three-dimensional formulations. Applying the plane-stress solution to the multi-layered composite plate, it is considered that the executing time required to numerical calculations will be considerably reduced and thus response of an intelligent function will be improved.