轻质弱辐射的阻尼夹芯复合材料圆柱壳的优化设计

基于三维弹性理论,对阻尼夹芯复合材料圆柱壳在简谐点力作用下的振动声辐射进行优化研究。建立了以总质量、基频和模态阻尼为优化目标的多目标函数优化模型,对纤维层和芯层厚度分布和铺层方式进行优化设计;经与其他文献及"有限元+边界元"法得到的结果对比,验证了三维弹性理论的计算结果的有效性;分析了三明治夹芯圆柱壳的振动和声辐射的影响因素,发现芯层中面线位置高于整壳中面线时有利于提高基频,降低声辐射功率;且随着铺层角的增加,固有频率呈抛物线型变化趋势,模态阻尼比则逐渐减小。经优化设计,声功率一阶共振频率向高频方向偏移20 Hz,最大声功率降低11.66 dB,200 Hz以下的低频段,声功率峰值密度明显降低。

Optimization for composite cylindrical shells with light and weak-radiation damping sandwich

The vibration and acoustic radiation of composite cylindrical shells with damping sandwich (CCSDS) activated by pointed harmonic force were studied based on Three-dimensional elastic theory (TDET). A multi-objective function optimization model was built, whose Optimization objectives were total mass, fundamental frequency and model damping. The model was used to optimize the thickness distribution of fiber and sandwich layer as well as the modes of lay-up. The effectiveness of TDET was confirmed after compared with the results of other literatures and “FE-BE” method. The influencing factors for vibration and acoustic radiation of CCSDS were analyzed. It is revealed that when the sandwich layer’s median line is higher than the whole shell’s, it is favorable for increasing the fundamental frequency and reducing acoustic radiation power. With the increasing of lay-up angle, the natural frequency changes in the shape of parabola and modal damping ratio decreases gradually. After optimization, the first modal frequency of acoustic radiation power shifts to higher frequency by 20Hz and maximum acoustic power decreases by 11.66dB. The peak value density decreases apparently in the low-frequency stage of under 200Hz.