As technology continues towards smaller, thinner and lighter devices, more stringent demands are placed on thin polymer films as diffusion barriers, dielectric coatings, electronic packaging and so on. Therefore, there is a growing need for testing platforms to rapidly determine the mechanical properties of thin polymer films and coatings. We introduce here an elegant, efficient measurement met...

Elastic constants and cross-sectional dimensions of imprinted nanolines of poly(methyl methacrylate) (PMMA) on silicon substrates are determined nondestructively from finite-element inversion analysis of dispersion curves of hypersonic acoustic modes of these nanolines measured with Brillouin light scattering. The results for the cross-sectional dimensions, under the simplifying assumption of v...

We report a new class of tunable and switchable acoustic metamaterials comprising resonating units dispersed into an elastic matrix. Each resonator consists of a metallic core connected to the elastomeric matrix through elastic beams, whose buckling is intentionally exploited as a novel and effective approach to control the propagation of elastic waves. We first use numerical analysis to show t...

Three forms of elastic and plastic deformations at Au(111) surfaces have been observed by high-resolution electron microscopy. These are normal expansion of the first surface interplanar spacing, lateral expansions through surface dislocations, and the development of hill-and-valley structure or elastic buckling depending upon the sample morphology. These effects are interpreted as evidence for...

geometrically nonlinear governing equations for a plate with linear viscoelastic material are derived. the material model is of boltzmann superposi¬tion principle type. a third-order displacement field is used to model the shear deformation effects. for the solution of the nonlinear governing equations the dynamic relaxation (dr) iterative method together with the finite difference discretizati...

We analyze the structure of the Föppl-von Kármán shell equations of linear elastic shell theory using surface geometry and classical invariant theory. This equation describes the buckling of a thin shell subjected to a compressive load. In particular, we analyze the role of polarized Hessian covariant, also known as second transvectant, in linear elastic shell theory and its connection to minim...

This paper is concerned with the elastic buckling of pumpkin-shaped balloon structures. Pumpkin balloons, currently being used in the NASA Ultra-Long Duration Ballooning (ULDB) Program, consist of stiff meridional tendons that constrain a thin, highly curved plastic surface. The present study exploits the high degree of symmetry of this design by adopting a newly developed, closed form expressi...

Asymptotic buckling analysis of elastic structures can be considered a well established procedure (Budiansky, 1974) . It consists in bifurcation analysis of a system of oneparameter differential equations: balance, compatibility and constitutive equations . The aim of this work was to experiment with the use of automatic symbolic computation in the asymptotic bifurcation analysis of elastic bea...