Dynamic Response of Laminated FRP Composite Made Cracked Spherical Shells Subjected to Free Vibration

Abstract

Three dimensional finite element analyses based modelling and simulation technique has been developed in the present research to study the dynamic response of laminated FRP composite made spherical shell structures along with interlaminar through-the- thickness cracks. The developed fracture model has been yielding results in close agreement with literature. Interlaminar cracks of similar sizes have been considered at edge and internal locations in order to study their effect on natural frequency of vibration of the cantilevered spherical composite shell structure. Cracks have been simulated in different locations from the clamped towards the free edge in order to study their effect on free vibration of the laminated shell structure. Interlaminar cracks have been observed to be reducing the natural frequency of vibration of the shell structures to a great extent, hence affecting the stiffness of the structure. However, for similar damage size and locations, edge-cracked composite spherical shells are comparatively stiffer than the edge-cracked spherical shell structures. Both the edge and internal cracks emanating towards the free edge of the shell structure are comparatively safe as the natural frequency of vibration is marginally affected. However, the fractures emanating towards clamped edge are more deteriorating towards the dynamic response of the composite shell structure.