Vibration and Fatigue Analysis of Composite Materials

Abstract

Along with the advance of science and technology, composite materials including laminated composite plates have been widely used in various engineering Held such as in aeronautic, astronautic .auto- industries, submarine engineering, nuclear technology .and also for the fine construction such as circuit boards in electronic packages, thereby creating considerable interest in their analysis. It is inevitable to determine properties or lamina from known properties of fiber and matrix, natural frequencies, no. of cycles to failure as a pan to ensure the safe design of the component. As an alternative for determination of properties of lamina by experimental method which is expensive, method of cells is widely used. In the present work an algorithm is developed to determine properties of lamina from known properties of fiber and matrix. An algorithm is also developed for determinations of natural frequency of plates made of composite materials with various boundary conditions. Results so obtained are compared by performing analysis using ANSYS, Fatigue failure of composite material has always been an important problem in the application of composite structures. The fatigue behavior of composite materials is conventionally characterized by S - N curve or damage mechanisms. For every new material with a new lay-up, altered constituents or different processing procedure, a whole new set fatigue life tests has to be repeated. An algorithm is developed that includes the effect of stress ratio(R) and load frequency (f) for the prediction of fatigue life and residual strength of composite structures.