You need to read in detail the references I advise you. Model is must to analyze the fatigue characteristics of composite.
Fatigue of composite materials presents a tremendous challenge when one considers the number and variety of parameters that can possibly affect the governing mechanisms. It is worth noting that because of the large number of parameters in composite materials (constituent properties, ply orientations, woven and other complex architectures, etc.) the empirical path is highly inefficient. To lessen this challenge, framework in the form of fatigue life diagrams will allow assessment of the effects of constituent properties, such as fiber stiffness and matrix ductility, and provide guidelines for fatigue design as well as for developing mechanisms based life prediction models. As we know, fibers of different materials, e.g., glass, carbon and SiC, have different axial modulus and fail at different axial tensile strains. Similar Continuum damage mechanics concepts can be used to evaluate the degradation of composite materials under cyclic loading. You need to work with analytical model (damage accumulation model) to capture the unique characteristics of composite materials. Generally, to characterize the buckling of long laminated composite cylindrical shells, combined loads of axial compression and torsion can be examined on the basis of Flügge’s theory.
***Follow suit the detail study the reference site given below. First reference may be utmost useful for understanding of fatigue of composite materials.
Fatigue is the main failure mechanism for structures under cyclic loading. The fatigue behavior of one constituent may be significantly affected by the presence of other constituents and the interfacial regions between the fibers and matrix. The book chapter “Fatigue of Composite Materials” has some useful information which might be helpful in your quries. Please reade the chapter via the link: