Parametric Study of Hydroforming of Paper Materials Using the Explicit Finite Element Method with a Moisture-dependent and Temperature-dependent Constitutive Model

Abstract

A moisture-dependent and temperature-dependent constitutive model for paper materials was proposed and implemented into a finite element model of the paper hydroforming process. Experimental hydroforming was conducted at temperatures of 23C and 110 C and moisture contents of 6.9 and 10.6 (respectively corresponding to 50 and 80% relative humidity). The proposed model, which also included the effects of drying, captured the extent of forming of all experimental results within reasonable accuracy. For the moisture content and temperature conditions in this study, the phenomenon of drying was found to be the reason why the application of temperature had a much greater effect on the degree of forming than hydroforming at various moisture contents. A simulation-based parametric study was conducted in order to identify the importance of various process and material parameters. This parametric study confirmed many previous empirical findings and was capable of quantifying the extent to which these process and material parameters affect the three-dimensional formability of paper. The coefficient of friction was identified as one of the most important factors when determining the extent of forming.