Theory of the Compression Hysteresis of Fibrous Assemblies

Abstract

An analysis of a fibrous assembly at large deformations has been explored as a means of predicting the compressional behavior, especially the compression hysteresis. The essential principle is to classify all the fiber contact points in the assembly as either slipping or nonslipping, so they can be dealt with separately. The compressional modulus and Poisson's ratio are derived and shown to be dominated by the mechanical properties and the directional distribution of the individual fibers within the assembly. An iterative algorithm, in which the system geometry is updated on successive incre ments, is developed to cope with large and nonlinear deformations. A comparison between the theoretical prediction and the experiment has indicated reasonable agree ment. An improvement could probably be achieved by including the contribution of fiber viscoelasticity to the total hysteresis.