嵌入多层黏弹性胶膜复合材料阻尼工字梁的多目标设计优化

针对嵌入多层黏弹性胶膜的复合材料阻尼工字梁,传统的混合单元法在进行结构动态分析与设计优化时存在很大困难的问题,采用基于离散层理论的多层梁单元建模分析复合材料阻尼工字梁.通过对正交各向异性铺层和腹板进行等效处理的方法,对工字梁凸缘嵌入单层阻尼层模型进行参数化分析;分别对嵌入多层或单层阻尼层的模型建立多目标优化模型,优化目标为模态损耗因子和固有频率最大化,设计变量为阻尼层层数（厚度）及其嵌入位置;应用多目标遗传算法进行优化求解.结果表明：基于离散层理论的阻尼梁单元计算精度好且易于优化,对于嵌入单层较厚阻尼和嵌入多层较薄阻尼的复合材料工字梁,获得的阻尼效果与动刚度损失基本相当,但对于高阻尼的方案,前者比后者的动刚度损失更大.

Multi-objective design optimization on composite damping I-shaped beam with cocured embedded viscoelastic layers

As to the issue that it is difficult to analyze and achieve design optimization on composite damping I shaped beam with embedded multi layer viscoelastic films by traditional hybrid finite element model, multi layer beam element based on layerwise theory is used to analyze composite damping I shaped beam. Parametrization analysis is performed on I shaped beam embedded with single damping layer in each flanges; two multi objective optimization models are established for the models with multi layer or single layer damping layer, of which the optimization objectives are maximization of modal loss factor and natural frequency and the design variables includes damping layer number(thickness) and the embedded location; the optimization is solved by multi objective genetic algorithm. The results indicate that the computation has good precision and is easy to be optimized by damping beam element based on layerwise theory, the composite I shaped beam embedded with one thicker layer has similar damping performance and dynamic stiffness loss compared with the one that is embedded multiple thinner layers, but the former may loss more stiffness than the latter when the damping is high.