Dynamic Response of Laminated Composite Plates

Abstract

HE classical method of separation of variables combined with the Mindlin-Goodman procedure1 is employed to analyze the dynamic response of an infinitely long simplysupported composite plate under a uniform dynamic pressure, P0, on the upper surface of the plate. Two cases of dynamic pressures are considered; 1) the magnitude of the uniform pressure remains unchanged, and 2) the magnitude of the uniform pressure increases linearly as a function of time and then remains constant. Numerical results for eight layer granite/epoxy and glass/expoxy composites with (0/0/0/ — 0) s and (#/ — 0/0/0)5 stacking sequences are evaluated. Dynamic response characterized in terms of normal displacement, bending stress, interlaminar shear stress, and interlaminar normal stress are evaluated and compared with the corresponding quantities obtained statically (i.e., a dynamic load factor is established). It is observed that the dynamic values are consistently twice the corresponding static values for Case 1, and varies from one to two times the corresponding static values for Case 2. Contents The equations of motion, including transverse shear deformation and rotary inertia, for an infinitely long laminated composite plate under cylindrical bending are given in Ref. 2. The solution to the governing equations in terms of separation of variables in conjunction with the Mindlin-Goodman procedure] is also presented in Ref. 2. In the present paper the interlaminar shear stress TXZ is determined by integrating the equation of motion (1) with respect to z using the condition Txz(±h/2,t) = 0 and the condition of continuity at the interfaces. Once rxz(k) is determined the interlaminar normal stress ozz (k) can also be determined by integrating the equations of motion