There is a growing interest in developing non-destructive damage detection methods for damage assessment of composite structures, especially in the aerospace and marine industries. Although damage detection of composite laminates has been widely investigated, little work has been carried out on sandwich composite configurations. A technique using the Lipschitz exponent, which is estimated by wa...

The goal of this work is to define the structural and sequence features common to sandwich-like proteins (SPs), a group of very different proteins now comprising 69 superfamilies in 38 protein folds. Analysis of the arrangements of strands within main sandwich sheets revealed a rigorously defined constraint on the supersecondary substructure that holds true for 94% of known SP structures. The i...

Loss factor measurements were performed on different sandwich panels to determine the effects of different skin and core materials on the acoustical properties of sandwich structures. The study included the following panel/beam designs: glass-epoxy skin with a meta-aramid (m-aramid) core, glass-epoxy skin with a para-aramid core, carbon skin with a m-aramid core, carbon skin with a m-aramid cor...

The topology optimization design of structures with anisotropic constrained damping layers (ACDL) is investigated in present paper. The evolutionary structural optimization (ESO) method is employed to find the optimal layout of ACDL with aim to maximum the modal damping loss factor of the sandwich structure. Modal strain energy (MSE) method is used to calculate the damping loss factor of whole ...

The structures realized using sandwich technologies combine low weight with high energy absorbing capacity, so they are suitable for applications in the transport industry (automotive, aerospace, shipbuilding industry) where the “lightweight design” philosophy and the safety of vehicles are very important aspects. While sandwich structures with polymeric foams have been applied for many years, ...

tetrachloride in T H F produces blue-green crystals that are stable to water and to aqueous acid or alkali. The compound can be sublimed or recrystallized from benzene or toluene. The compound is pyrophoric but controlled air oxidation yields uranium oxides and cyclooctatetraene. Mass spectral analysis gives a parent peak for U(CeH& and the fragmentation pattern indicates a ferrocene-like sandw...

A study on the bending response of a composite curved panel with pyramidal metallic truss cores suitable for functional applications is presented using a combination of analytical modeling, three-point bending experiments and finite element (FE) based simulations. The aluminum pyramidal cores were constructed using an interlocking method before curing with composite face sheets to fabricate the...

Detection of debonds at sharply curved edges on sandwich structures is found difficult using conventional nondestructive testing (NDT) techniques. The advantages of digital holography and time average holographic interferometry were utilized to evolve a new approach to detect debonds on curved sandwich structures which is reported in this paper. Software developed for the high-speed recording, ...

Sandwich structures are widely used in many industrial applications and especially light aviation. The local buckling phenomenon named “wrinkling” is one of the primary causes compressive failure such structures. Its calculation a difficult practical problem since this cannot be captured by GFEM (Global Finite Element Model) classically for aircraft structure sizing. Therefore, pre-sizing invol...

A method is proposed to identify the mechanical properties of the skin and core materials of sandwich structures having heterogeneous cores. All the elastic coefficients and loss-factors that matter in the dynamics of such a panel in the thick-plate approximation are identified. To this end, experimental natural modes (i.e. eigenmodes of the damped system) are compared to the numerical modes of...