Fatigue Analysis of Composite Structures

Abstract

Composite materials are finding increased use in structural application, a micromechanics theory based on the analysis of repeating cell in a fiber-reinforced material is reviewed to get composite properties. The analysis leads to the prediction of overall behavior of various types of composites from the known material properties of fiber and matrix on average basis. The capability of the theory in providing the response of elastic, thermal, and strength is demonstrated. This method is well known as “Method of cells”.

The same approach of repeating cell is used in inverse micromechanics. The analysis is used to predict the behavior of various fibers from the known material properties of matrix and lamina. The various properties of fiber predicted are elastic, thermal and strength properties.

In the present study, developed inverse micromechanical model along with the model available for micromechanics to predict the properties of fiber and lamina, which provides the basic properties required for stress analysis and fatigue analysis of Composite.

The fatigue life and the mechanical properties of composite materials depend on many factors including the matrix material, fiber material, volume fractions, fiber orientation, moisture content, porosity, applied stress, strain rate, and stress amplitude.

The fatigue behavior of composites has been shown to be highly dependent on the stress ratio, R; and the frequency of applied cyclic load f. The Jayantha’s model is used to predict the fatigue behavior of a composite material using S – N curve approach. This covers the overall fatigue analysis of “Composite analyzer”, “Composite Fatigue Analysis” as a part of “E-Composite” and then “E-Fatigue”.

The results are compared with other methods micromechanical and macromechanical models for lamina properties and fatigue life with experimental results available in literature.