Validating wrinkling models for nonlinear membranes.

Stabilizing and validating sub-grid wrinkling models for nonlinear membranes is essential to accurately capture cloth behavior under compressive stress states (loss of tension, localization, and strong anisotropy). In our experience, robust convergence and consistent wrinkle patterns require a carefully stabilized formulation and time integration in the strongly nonlinear regime.

Here is our validation of our implementation of the wrinkling model from Amphon Jarasjarungkiat et al. (2008): material-modification approach with crease / wrinkle direction computation. The implementation is benchmarked directly against the reference cases and results reported in the paper: https://lnkd.in/dA2kQhdK

The attached annulus test applies an internal rotation at the inner boundary, comparing isotropic cloth (left) and orthotropic cloth (right). Von Mises stresses are depicted, while the black segments indicate the predicted wrinkle (crease) directions.

This is an important building block for simulating flexible airfoils : paragliders, parachutes, kites, and other ram-air / ILE wings, where wrinkling strongly impacts the load path, shape, and overall performance.

#FEM #FSI #NonlinearMembranes #Wrinkling #Orthotropy #Aeroelasticity #Paragliding #Parachutes #KiteDesign