An exact two-dimensional approach to fiber micro-buckling (Q1089172)

Fiber micro-buckling is studied within the context of a two-dimensional (lamellar) model. A bifurcation approach, which rigorously accounts for finite strains and material nonlinearity in both constituents, is employed to examine the possibility of shear and extensional micro- buckling modes. Numerical results for a range of material and geometric parameters are presented, and an asymptotic bifurcation condition is developed for long wavelength shear modes. It is found that shear modes are preferred at higher fiber volume fractions and extensional modes at lower fiber fractions. However, the transition fiber volume fraction, which depends strongly on material nonlinearity, may be higher than previously expected. The distinction between mechanical loading and thermal loading (where one constituent goes into tension and one into compression) is also touched upon briefly.