User login

You are here

Fan Xu's blog

Fan Xu's picture

A modeling and resolution framework for wrinkling in hyperelastic sheets at finite membrane strain

Wrinkles commonly occur in uniaxially stretched rectangular hyperelastic membranes with clamped-clamped boundaries, and can vanish upon excess stretching. Here we develop a modeling and resolution framework to solve this complex instability problem with highly geometric and material nonlinearities. We extend the nonlinear Foppl-von Karman thin plate model to finite membrane strain regime for various compressible and incompressible hyperelastic materials.

Fan Xu's picture

Roll up your sleeves

When you push up your sleeves, wrinkles form, which eventually evolve into ridges (pictured). As familiar as you may be with this phenomenon, have you ever thought about its underlying mechanism? It involves the complex nonlinear mechanical behaviour of large deformations and surface instabilities, which in turn give rise to a sophisticated morphological evolution. And now, Yifan Yang and co-workers have revealed a hitherto unknown post-buckling behaviour that involves multiple bifurcation transitions (Phys. Rev.

Fan Xu's picture

Photo-controlled patterned wrinkling of liquid crystalline polymer films on compliant substrates

Photo-chromic liquid crystalline polymer (LCP) is a type of smart materials which are sensitive to light. Here we harness its photo-mechanical response to flexibly control surface patterning, through modeling a film involving homeotropic nematic liquid crystals with director perpendicular to the polymer film attached on a compliant substrate. Theoretical and numerical analyses were conducted to explore the surface instability of such film/substrate systems under both uniform and non-uniform illuminations by ultraviolet (UV) light, respectively.

Fan Xu's picture

A multi-scale modeling framework for instabilities of film/substrate systems

Spatial pattern formation in stiff thin films on soft substrates is investigated from a multi-scale point of view based on a technique of slowly varying Fourier coefficients. A general macroscopic modeling framework is developed and then a simplified macroscopic model is derived. The model incorporates Asymptotic Numerical Method (ANM) as a robust path-following technique to trace the post-buckling evolution path and to predict secondary bifurcations.

Fan Xu's picture

Bridging techniques in a multi-scale modeling of pattern formation

F. Xu, H. Hu, M. Potier-Ferry, S. Belouettar

International Journal of Solids and Structures (2014), doi: http://dx.doi.org/10.1016/j.ijsolstr.2014.05.011

 

Abstract:

Subscribe to RSS - Fan Xu's blog

Recent comments

More comments

Syndicate

Subscribe to Syndicate