Wrinkling of Orthotropic Viscoelastic Membranes

Abstract

This paper presents a simplified simulation technique for orthotropic viscoelastic films. Wrinkling is detected by a combined stress-strain criterion and an iterative scheme searches for the wrinkle angle using a pseudo-elastic material stiffness matrix based on a nonlinear viscoelastic constitutive model. This simplified model has been implemented in ABAQUS/Explicit and is able to compute the behavior of a membrane structure by superposition of a small number of response increments. The model has been tested against a published solution for a time-independent isotropic membrane under simple shear and also against experimental results on StratoFilm 420 under simple shear.

A Technique to Predict Clefting of Lobed Super-Pressure Balloons

“…Young's Modulus and Poisson's ratio are averaged between the machine direction and the transverse direction of the film. 17 In the present case we have determined that for a balloon subject to uniform pressure Δp = 10 Pa, at room temperature T = 293 K for t = 1 hour an isotropic pseudo-elastic modulus of approximately 250 MPa can be assumed. This value was used for all of the simulations presented in this paper.…”

“…The balloon film is made of Linear Low Density Polyethylene (LLDPE), which is a visco-elastic material, whose behavior depends on stress σ, temperature T and loading time t. Rand developed a nonlinear viscoelastic constitutive model for this film material based on Schapery's theory and subsequently we introduced an approximate pseudo-elastic constitutive model that allows for visco-elastic effects in a simplified way. 17 The anisotropy of the balloon film is sufficiently weak that an isotropic wrinkling model can be assumed. Young's Modulus and Poisson's ratio are averaged between the machine direction and the transverse direction of the film.…”

Deployment Dynamics of Thin-Shell Space Structures

“…Various implementations of the IMP algorithm have been successfully used in finite element codes, with both implicit [31] and explicit [32] integration schemes. The particular implementation that was used in the present study was the Abaqus/Explicit VUMAT subroutine in Ref.…”

Deployment Dynamics of Foldable Thin Shell Space Structures

“…Various implementations of the IMP algorithm have been successfully used in finite element codes, both with implicit [47] and explicit [48] integration schemes. Hence, an implementation of the IMP model as a VUMAT was used in the Abaqus Explicit simulations presented in the rest of this paper.…”