Vibration Of Composite Shallow Shells Research Articles

Analysis for Vibration of Laminated Shallow Shells with Non-Uniform Curvature

Despite a large number of technical papers on vibration of composite shallow shells, all the previous papers have dealt with shallow shells with uniform curvature to avoid difficulty in the analysis. Recent composite products, however, require various surface designs of thin panels from the viewpoint of industrial design, for example, in the fender and door panel designs of commercial vehicles. The present study proposes an analytical method to deal with vibration of shallow shells with non-uniform curvature. An interpolating function is introduced to represent the required surface shape and the corresponding curvature is derived as a function of the position (x,y). The obtained curvature is substituted into the total potential energy of the shell, and the procedure is shown to derive a frequency equation in the Ritz method. Numerical examples clarifies the effects of non- uniform curvature on the natural frequencies and mode shapes.

Effects of general laminations and boundary constraints on vibration of composite shallow shells

This paper presents a comprehensive parametric study on the essential effects of symmetric and unsymmetric fibre orientations on vibration of thin, composite double curved (cylindrical, spherical and hyperbolic paraboloidal) shallow shells with arbitrary and complex boundary constraints. The precise strain and kinetic energy integral expressions for the laminates are formulated by using the extremum energy principle with no restrictions on the number of laminations and fibre orientations. A versatile and flexible general method of solution for vibration of composite laminates is developed. Convergence and comparison studies are reported to verify the consistency and accuracy of this analysis method. New results are presented for simply supported and fully clamped laminated shells with multiple laminations, symmetric and unsymmetric stacking sequences for two types of composite materials. The influence of fibre angles and stacking sequences on vibration mode shapes is also illustrated.