Steady state creep behavior of short fiber composites by mapping, logarithmic functions (MF) and dimensionless parameter (DP) techniques

A new mathematical insight based on logarithmic, polynomial mapping functions (MF), and dimensionless parameter (DP) models is presented for determination of some unknowns in the steady state creep stage of short fiber composites subjected to axial loading. These unknowns are displacement rate in outer surface of the unit cell, shear and equivalent stresses at interface and outer surface of the unit cell, and average axial stress in fiber. Dimensionless parameter technique is presented for determination of displacement rate and equivalent stress in outer surface of the unit cell. However, the polynomial mapping function is presented for determination of average axial stress in fiber. Most important novelty of the present research work is determination of the mentioned unknowns in steady state creep by DP and MF techniques without using the shear-lag theory unlike the previous researches. Good agreements are found among the new approaches and previous analytical results based on the shear-lag theory and also numerical solutions (FEM) for predicting the steady state creep behavior in short fiber composites.

► Defining the 2nd stage creep strain rate of short fiber composites without using the shear-lag theory. ► Mapping function and dimensionless parameter techniques are presented. ► Determination of some unknowns in second stage creep of short fiber composites under axial loading. ► Good agreements are found between the new presented approaches and previous researches.