We compute the stresses in an elastic medium confined in a vertical column, when the material is at the Coulomb threshold everywhere at the walls. Simulations are performed in 2 dimensions using a spring lattice, and in 3 dimensions, using the Finite Element Method. The results are compared to the Janssen model and to experimental results for a granular material. The necessity to consider elast...

The article presented two proposals for construction of a flexible element with variable stiffness, in which construction is limited, or is it completely eliminated the mechanical elastic member such as spring. Their properties vary in the extent applicable member stiffness and speed of reaction to contact with an obstacle. By limiting, or eliminating the mechanical elastic member can be achiev...

The recently developed Spring Back Reflector has low stiffness in the deployed configuration. A general method of stiffening this type of reflector without changing its folding properties is presented. The stiffening is achieved by adding a conical skirt around the edge of the dish; this skirt snaps elastically when the dish is folded. The paper concludes that it is possible to design spring ba...

We discuss the classical motion of a spring of arbitrary mass coupled to two arbitrary massive blocks attached at its ends. A general approach to the problem is presented and some general results are obtained. Examples for which a simple elastic function can be inferred are discussed and the normal modes and normal frequencies obtained. An approximation procedure to the evaluation of the normel...

Abstract: There are two classes of phononic structures that can support elastic waves with non-conventional topology, namely intrinsic and extrinsic systems. The non-conventional topology of elastic wave results from breaking time reversal symmetry (T-symmetry) of wave propagation. In extrinsic systems, energy is injected into the phononic structure to break T-symmetry. In intrinsic systems sym...

This experiment was conducted in attempt of improving hydrodynamic efficiency of the propulsion mechanism by installing a spring to the wing so that the opening angle of the wing in one stroke can be changed automatically, compared to the existing method of fixed maximum opening angle in Weis-Fogh type ship propulsion mechanism. Average thrust coefficient was almost fixed with all velocity rati...

Deployable structures made from ultrathin composite materials can be folded elastically and are able to selfdeploy by releasing the stored strain energy. This paper presents a detailed study of the folding and deployment of a tape-spring hingemade from a two-ply plain-weave laminate of carbon-fiber reinforced plastic. A particular version of this hinge was constructed, and its moment-rotation p...

In this study, numerical analysis of a composite spring with nonlinear elastic force-displacement relationship was performed. Due to the lightness and durability materials, their use in automotive industry is increasing production methods allow for high performance design. The behavior pair leaf springs working tandem cross-section profiles be obtained by using involute curve spur gear pairs un...

The expression of male secondary sexual traits can be dynamic, changing size, shape, color, or structure over the course of different seasons. However, the factors underlying such changes are poorly understood. In male Anolis carolinensis lizards, a morphological secondary sexual signal called the dewlap changes size seasonally within individuals. Here, we test the hypothesis that seasonal chan...

An analytical method of integrating ordinary differential equations with non-constant coefficients arising from an elastic membrane concept for inverse shape design is presented utilizing Fourier series formulation. The non-homogeneous ordinary differential equation with non-constant coefficients mimics forced oscillations of a system of mass-damper-spring elements linked in parallel where coef...