Parametric Instability Analysis and Experiment of Laminated Composite Shell

摘要

The parametric instability of graphite/epoxy laminated composite shell was investigated analytically and experimentally. The dynamic system of the laminated composite shell was derived based on the finite element modeling and the Lagrange's equation. The normalized modal expansions of the composite shells were then applied to obtain a dynamic equation of Mathieu's type, which contains parametric excitation terms. In experiment an electromagnetic device, acting like a spring with alternating stiffness, was used to excite the laminated shell parametrically in the transverse direction. The instability regions of the composite shell were identified by the transition curves, which were functions of the modal parameters of the composite shell and the position, the stiffness of the electromagnetic device attached on the composite shell. The experimental results were found to agree well with the analytical ones.