# Modeling Analysis of Complex Deformation of Woven Coating Film during the Cyclic Tensile Process

## TL;DR

This paper improves models for predicting how woven coated films deform under cyclic tension at different temperatures.

## Contribution

The study introduces a 2D nonlinear orthotropic model and an improved 1D Burgers model for better cyclic deformation prediction.

## Key findings

- The 1D model improves prediction accuracy by considering time-dependent viscosity and elastic-to-viscous deformation ratios.
- The 2D model uses a polynomial-based approach with an inverse algorithm to avoid difficult shear tests.
- Simulation results validated the 2D model's effectiveness in tension-shear coupling states.

## Abstract

It is difficult for the existing Burgers model to accurately depict the off-axis cyclic drawing process of woven coatings. In this paper, the mechanical deformation of woven PVC (polyvinyl chloride)-coated film at different temperatures is investigated. One-dimensional (1D) and two-dimensional (2D) constitutive models were established to characterize cyclic deformation processes. The 1D model is an improved Burgers model. The effects of the time dependence of the viscosity coefficient and the ratio of elastic to viscous deformation are considered simultaneously. The accuracy of the 1D model for predicting the cyclic nonlinear deformation at different temperatures and loading rates is improved. The 2D model is a nonlinear orthotropic model using polynomials. On the basis of the single-objective genetic algorithm, the inverse algorithm is used to obtain the shear polynomial coefficients in the tension phase and the shear modulus in the unloading phase, which circumvents performing the difficult shear test. UMAT subroutines of off-axis stretching and off-axis cyclic stretching are written separately. The intelligent inverse algorithm program consists of a single-objective genetic algorithm program, a finite element parametric modelling program, and a UMAT subroutine. The simulation results are compared with the off-axis cyclic tensile test data to validate the effectiveness and accuracy of the proposed 2D model for the analysis of the woven PVC-coated films in the tension–shear coupling state.