積層偏平シェルの基本振動数最大化と解の近似による影響について

抄録

The optimal design problem of free vibration is solved for laminated composite shallow shells of rectangular planform. The shelts have symmetric laminated construction and are supported by shear diaphragms along the edges. The first-order transverse shear deformation is assumed in the Donnell type shell theory to account for the thickness shear effect, and an approximate solution is presented for angle-ply laminates. A simplified formula is derived by neglecting inplane and rotational inertia terms. Analytical solutions with/without the inplane inertia terms from the classical thin shell theory are also shown. In numerical examples for two types of shell curvatures, e.g., circular cylindrical and spherical shells, fiber orientation angles which cause the maximized fundamental frequencies of the alternating angle-ply shells are determined, and effects of using the four different vibration solutions are discussed on the optimal frequencies and fiber orientation angles.