The design of light aircraft sandwich structures is driven by a local buckling phenomenon named “wrinkling” which can be the primary cause failure such structures. Structural tests using VERTEX methodology were performed to access wrinkling behaviour 558x536 mm 2 technological specimens representative used in aviation. operating principle machine use four hydraulic actuators load rectangular bo...

The surface sculpture of the inoceramid bivalve Magadiceramus? rangatira rangatira consists of commarginal ribs and curious, transverse wrinkles. The wrinkles typically are at a high angle or orthogonal to the shell margin (‘antimarginal’) and thus differ from purely radial structures. They show features of distribution and morphology that reveal them to be products of margin-parallel compressi...

The repetitive exposure of skin to ultraviolet B (UVB) preferentially elicits wrinkling while ultraviolet A (UVA) predominantly elicits sagging. In chronically UVB or UVA-exposed rat skin there is a similar tortuous deformation of elastic fibers together with decreased skin elasticity, whose magnitudes are greater in UVB-exposed skin than in UVA-exposed skin. Comparison of skin elasticity with ...

We demonstrate a novel approach for controlling the formation of line-defects in wrinkling patterns by introducing step-like changes in the Young's modulus of elastomeric substrates supporting thin, stiff layers. Wrinkles are formed upon treating the poly(dimethylsiloxane) (PDMS) substrates by UV/Ozone (UVO) exposure in a uniaxially stretched state and subsequent relaxation. Line defects such a...

In order to solve the problem that due to the unreasonable parameter Settings when use CAE analysis to produce the cars covering parts mould, such as sheet wrinkling, cracking, and more than an acceptable range of rebound. This article used CAE analysis software to find relatively reasonable parameters to achieve a reasonable analysis in the process of sheet metal forming defects and to put for...

The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic-early Middle Jurassic) in Central Patagonia (Argentina), which may help ...

We present the results of an experimental investigation on the wrinkling of positively curved surfaces and explore their use towards drag reduction applications. In our precision model experiments we make use of rapid prototyping techniques to cast samples with custom geometry and material properties out of silicone-based rubbers. Our structures consist of a thin stiff shell that is chemically ...

Complex wrinkle patterns have been observed in various thin film systems, typically with integrated hard and soft materials for various applications as well as in nature. The underlying mechanism of wrinkling has been generally understood as a stress-driven instability. On an elastic substrate, equilibrium and energetics set the critical condition and select the wrinkle wavelength and amplitude...

Textured surfaces, formed through wrinkling and folding, are observed abundantly in nature. We are especially motivated by the unique capabilities of some species of cuttlefish that camouflage themselves by rapidly switching from smooth to textured skin by expressing protuberances called papillae. Inspired by this, we developed a shape memory alloy– elastomer composite as a platform for reversi...