Abstract:

Thin-film membrane structures are a common element in many of the structures that are currently envisaged for space missions and the presence of wrinkles in these membrane structures may significantly influence both the static and dynamic behaviour of space systems.  It is, therefore important to carry out an in-depth study of the highly geometrically nonlinear behaviour of wrinkled structures.

This dissertation investigates a square membrane of uniform, elastic, isotropic material, with four edges clamped to two identical rigid square frames on both surfaces.  The tensions rays, and hence the membrane stresses, amplitude and wavelength of the wrinkles due to shear load are carefully investigated.

A simple analytical approach is proposed to predict the wrinkle wavelength and out-of-plane amplitude.  An initial analytical model is based on the assumption that a membrane is able to resist a small critical buckling stress once it has wrinkled.  Two different methods are used to predict the wrinkle amplitude.  Following a comparison with the results from simulation and experiments, further corrections are introduced on the expression for the amplitude.

A finite element analysis has been carried out to analyse and predict the wrinkle patterns by using the ABAQUS commercial package.  The details of the stress field, wavelength and the amplitude are obtained from the simulation.  This study shows that Finite Element Method (FEM) can provide good estimates of the wrinkle behaviour.

An experimental study of a square membrane attached to aluminium frames is done.  The results show consistency of the wrinkle evolution patterns with the analytical model and the simulation results.  Although there are some differences between them, the experimental results generally are in good agreement with the parameters of wrinkles, in particular, wavelength and amplitude obtained from the simulation and theoretical analysis.