FE Analysis of Creep and Hygroexpansion Response of a Corrugated Fiberboarad to a Moisture Flow: a Transient Nonlinear Analysis

This paper presents a model using finite element method to study the response of a typical commercial corrugated fiberboard due to an induced moisture function at one side of the fiberboard. The model predicts how the moisture diffusion will permeate through the fiberboard's layers (medium and liners) providing information on moisture content at any given point throughout the structure. The hygroexpansion response and the creep response were predicted through the development of a finite element model capable of capturing the behavior of the fiberboard. Comparing the results generated from the model with actual experimental results validates the accuracy of the computational model. The model predicts the deformation response due to combined hygroexpansion and creep as the relative humidity rises from 38% RH to 86%. The parameters studied and calibrated include: the coefficient of moisture diffusion of the liner and the medium boards, the coefficient of moisture expansion, and the constants in the creep constitutive law. The results generated from the finite element model showed excellent agreement with the experimental results for a short column corrugated fiberboard and a board model representing a container box side-panel dimension. The results were generated in a cyclic relative humidity condition. A successful development of a reliable computational model holds the promise for analyzing collapse mechanism of container boxes in the service field under real weather condition data without dependency on expensive time-consuming experimental investigations. This is of great benefit to the shipping industry and the public.