Serhat Gokhan
Max Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart, Germany.
Materials (Basel). 2021 Jun 10;14(12):3203. doi: 10.3390/ma14123203.
This study concerns optimizing the eigenfrequencies of circular cylindrical laminates. The stiffness properties are described by lamination parameters to avoid potential solution dependency on the initial assumptions of the laminate configurations. In the lamination parameter plane, novel response contours are obtained for the first and second natural frequencies as well as their difference. The influence of cylinder length, radius, thickness, and boundary conditions on the responses is investigated. The lamination parameters yielding the maximum response values are determined, and the first two mode shapes are shown for the optimum points. The results demonstrate that the maximum fundamental frequency points of the laminated cylinders mostly lie at the inner lamination parameter domain, unlike the singly curved composite panels. In addition, the second eigenfrequency shows a nonconvex response surface containing multiple local maxima for several cases. Moreover, the frequency difference contours appear as highly irregular, which is unconventional for free vibration responses.
本研究关注于优化圆柱层合板的固有频率。通过层合参数来描述刚度特性，以避免潜在的解对层合板构型初始假设的依赖性。在层合参数平面中，获得了一阶和二阶固有频率及其差值的新型响应轮廓。研究了圆柱长度、半径、厚度和边界条件对响应的影响。确定了产生最大响应值的层合参数，并给出了最优点处的前两种振型。结果表明，与单曲率复合材料面板不同，层合圆柱的最大基频点大多位于内层合参数域。此外，在几种情况下，二阶固有频率显示出包含多个局部最大值的非凸响应面。而且，频率差轮廓显得高度不规则，这对于自由振动响应来说是不常见的。
