Sandwich-structured composite

About: Sandwich-structured composite is a research topic. Over the lifetime, 5853 publications have been published within this topic receiving 101126 citations.

Shear behavior of aluminum lattice truss sandwich panel structures

Abstract: Age hardenable 6061 aluminum tetrahedral lattice truss core sandwich panels have been fabricated by folding perforated sheets to form highly flexible cellular cores Flat or curved sandwich panels can be fabricated by furnace brazing the cores to facesheets Flat sandwich panels with core relative densities between 2 and 10% have been fabricated and tested in the σ ±13 shear orientation (minimum shear strength orientation for a tetrahedral lattice) in the fully annealed (O) and aged (T6) conditions The shear strength of the lattices increased with relative density, parent alloy yield strength and work hardening rate Analytical stiffness and strength predictions agree well with measured values for all relative densities and parent alloy heat treatments investigated The stiffness and strength of 6061-T6 aluminum tetrahedral lattice structures are shown to be comparable to those of conventional 5052-H38 aluminum closed cell hexagonal honeycombs and more than 40% stiffer and stronger than flexible honeycombs used for the cores of curved sandwich panels

An analytical model for composite sandwich panels with honeycomb core subjected to high-velocity impact

Abstract: In this paper, an analytical model for perforation of composite sandwich panels with honeycomb core subjected to high-velocity impact has been developed. The sandwich panel consists of a aluminium honeycomb core sandwiched between two thin composite skins. The solution involves a three-stage, perforation process including perforation of the front composite skin, honeycomb core, and bottom composite skin. The strain and kinetic energy of the front and back-up composite skins and the absorbed energy of honeycomb core has been estimated. In addition, based on the energy balance and equation of motion the absorbed energy of sandwich panel, residual velocity of projectile, perforation time and projectile velocity have been obtained and compared with the available experimental tests and numerical model. Furthermore, effects of composite skins and aluminium honeycomb core on perforation resistance and ballistic performance of sandwich panels has been investigated.

Vibration of laminate-faced sandwich plate by a new refined element

Abstract: An efficient 6-noded triangular element based on refined plate theory was developed for analysis of sandwich plates with stiff laminated face sheets and is applied to a free vibration problem in this paper. The plate theory represents parabolic through thickness variation of transverse shear stresses with continuity at the layer interfaces, which introduces discontinuity at these interfaces for the shear strains. The authors note that the plate theory requires unknowns at the reference plane only. Moreover, it ensures a shear stress-free condition at the top and bottom surfaces of the plate. Thus, the plate theory has all necessary features for an accurate modeling of laminated sandwich plates. The plate theory suffers from a problem in its finite element implementation since it requires C-sup-1 continuity of transverse displacement at the element interfaces. As very few elements based on this plate theory exist, and these possess certain disadvantages, an attempt has been made to develop this new element. It has been utilized to study some interesting problems of laminated sandwich plate.

Testing and modeling of Nomex™ honeycomb sandwich Panels with bolt insert

Abstract: Nomex™ honeycomb core sandwich panels with a bolt insert were load tested and modeled. The objective was to predict the honeycomb local buckling load and to identify a Nomex™ honeycomb constituent material model. Sandwich specimens were subjected to bolt pull-out load tests. The same sandwich structure was also tested in flat-wise tension with strain gages installed on the honeycomb walls. Finite element models of the flat-wise tension and bolt pull-out tests were built. The honeycomb geometry and strain gages were modeled with shell elements. An orthotropic honeycomb material model was identified by comparing the two test models to the experimental data. The material parameters identified are in the mid-range of previously published values. The pull-out test model was used to predict honeycomb wall buckling with a nodal rotation vector sum criterion. The buckling loads predictions closely corresponded to the start of the experimental load/displacement slope transition zone.

Free vibration analysis of composite sandwich plates

Abstract: The fibre reinforced plastic (FRP) composite materials configured as sandwich panels are finding increased usage in a variety of structural applications. An important facet in correct usage is an understanding of the dynamic behaviour of such structural configurations. This paper addresses the issue of natural frequencies of sandwich plate panels. The closed-form solutions are obtained using Reddy's first- and higher-order shear deformation theories. The approaches are validated against results from a standard, commercially available finite element analysis package. The paper concludes with a detailed investigation of the influence of variation in material property parameters and plate geometry variables on the natural frequency.