On the Elastic Buckling of Rod-Shaped Particles in Sheared Suspensions

Abstract

A correction of the original work by Forgacs and Mason describing the elastic buckling of rod-shaped particles in sheared suspensions is presented. Although the qualitative relationship among critical buckling conditions and the fiber aspect ratio and elastic modulus is unaltered, the new result for the predicted critical buckling condition shows that the resistance of suspended rods to buckling is more than five times greater than had been believed. Reexamination of experimental results using the corrected solution yielded mixed conclusions concerning the validity of the model. The agreement with results of the original experiments by Forgacs and Mason using Dacron fibers suspended in corn syrup and the new result was found to be excellent and quantitative. The results of experiments with glass fibers suspended in glucose solutions were found to be in poor agreement with predictions. The ability of the proposed result to account for an unusual degradation due to shearing in polystyrene melts of Kevlar 29 fibers was also found to be quantitative and excellent. The Kevlar fibers exhibited permanent bends spaced with a uniform spacing which was predicted by application of the new buckling relationship.