Modeling of compressive failure in fiber reinforced composites

The classical results of compressive strength in ®ber reinforced composites are brie¯y reviewed. The microbuckling analysis by Rosen (1965) and the Argon-Budiansky analysis for kink band formation (Argon, 1972; Budiansky 1983) are discussed and their results are rederived by using a new generalized Timoshenko beam model which is developed for a two-dimensional periodic matrix±®ber±matrix laminate. Introducing a `shear hingeʹ to simulate a kink band and using the method of split rigidities it is shown that not only an initial ®ber misalignment but also any misalignment in the loading system can a€ect the critical stress for kinking. A new mechanism based on shear instability of matrix is proposed for kink band formation and a simple formula is then derived to predict the kink band angle. Finally, a criterion for matrix yielding combining axial compressive stress and transverse shear perturbation is applied to modify the Argon±Budiansky kinking formula.