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 ...

Thermally induced film wrinkling is a fabrication and reliability challenge for thin-film stacks consisting of a compliant film capped by a stiffer film. The current understanding of film wrinkling is largely restricted to thin-film stacks on blanket substrates. An understanding of wrinkling in thin-film stacks on patterned substrates is of greater practical relevance to the microelectronic ind...

Wrinkles, folds, creases and other elastic surface instabilities play a crucial role in many systems in nature and engineering. While surface instabilities of ideal bilayer structures with large contrasts in elastic stiffness are well understood, many natural and man-made structures are far from this ideal. To better understand the behavior of systems with modest stiffness contrast, in particul...

Thin-walled tube bending is still to be considered a new and advanced technique. The process has been adopted into several industries such as aero and automotive. This process may produce a wrinkling, bulking and tearing phenomenon if the process parameters are inappropriate, especially for tubes with large diameter and thin wall thickness. Push bending process is one of the methods used for be...

Thickness in sub-10-nm metal film deposition is a seldom explored parameter that can influence not only the mechanical properties but also surface functional characteristics. In this study, we designed bilayer systems comprising Au on poly(dimethylsiloxane) (PDMS) substrate to reveal unique thickness-mediated morphology evaluation phenomenon. Our results show that, within specific range of elas...

Koiter's nonlinear plate theory is used to simulate the wrinkling patterns observed in stretched thin elastic sheets. The phenomenon considered is associated with wrinkle patterns distributed over the interior of the sheet, in regions where the stretching and bending energies are of the same order of magnitude. Numerical solutions to several equilibrium boundary-value problems are obtained by t...

A thin elastic sheet lying on a soft substrate develops wrinkled patterns when subject to an external forcing or as a result of geometric incompatibility. Thin sheet elasticity and substrate response equip such wrinkles with a global preferred wrinkle spacing length and with resistance to wrinkle curvature. These features are responsible for the liquid crystalline smectic-like behaviour of such...

The branching of un,symmetric equilibrium states from axisymmetric equilibrium states for clamped circular plates subjected to a uniform edge thrust and a uniform lateral pressure is analyzed in this paper. The branching process is called wrinkling and the loads at which branching occurs are called wrinkling loads. The nonlinear von Karman plate theory is employed. The wrinkling loads are deter...

By combining surface wrinkling and nanopatterned polymer films, we create anisotropic, hierarchical surfaces whose larger length-scale (wrinkling wavelength) depends intimately on the geometry and orientation of the smaller length-scale (nanopattern). We systematically vary the pattern pitch, pattern height, and residual layer thickness to ascertain the dependence of the wrinkling wavelength on...

Human non-hairy (glabrous) skin of the fingers, palms and soles wrinkles after prolonged exposure to water. Wrinkling is a sympathetic nervous system-dependent process but little is known about the physiology and potential functions of water-induced skin wrinkling. Here we investigated the idea that wrinkling might improve handling of wet objects by measuring the performance of a large cohort o...