Sandwich panel

About: Sandwich panel is a research topic. Over the lifetime, 4665 publications have been published within this topic receiving 49812 citations.

Low-energy impact response of composite sandwich panels with thermoplastic honeycomb and reentrant cores

Abstract: In the present study, the low-energy impact response of woven carbon fibre reinforced plastic (CFRP) composite sandwich panels with thermoplastic honeycomb and reentrant cores was investigated experimentally and numerically under three different impact energies (20 J, 40 J and 70 J). The Acrylonitrile Butadiene Styrene (ABS) honeycomb and reentrant core structures were manufactured in-plane and out-of-plane oriented via 3D printer, and adhesively bonded with two CFRP face sheets. The results indicate that the in-plane reentrant core based composite sandwich panel exhibits better impact strength and energy dissipation behavior than the in-plane and out-of-plane honeycomb core based composite sandwich panels.

Thermal Force and Moment Determination of an Integrated Thermal Protection System

Abstract: This paper is concerned with homogenization of a corrugated-core sandwich panel, which is a candidate structure for integral thermal protection systems for space vehicles. The focus was on determination of thermal stresses in the face sheets and the web caused by through-the-thickness temperature variation. A micromechanical method was developed to homogenize the sandwich panel as an equivalent orthotropic plate and calculate the equivalent thermal forces and moments for a given temperature distribution. The same method was again used to calculate the stresses in the face sheets and the core. The method was demonstrated by calculating stresses in a sandwich panel subjected to a temperature distribution described by a quartic polynomial in the thickness direction. Both constrained and unconstrained boundary conditions were considered. In the constrained case the plate boundaries are constrained such that there are no deformations in the macroscale sense. The unconstrained case assumes that there are no force and moment resultants in the macroscale. The results for stresses are compared with that from a three-dimensional finite element analysis of the representative volume element of the sandwich structure, and the comparison was found to be within 5 % difference. The micromechanical analysis, which is less time consuming, will be useful in the design and optimization of integral thermal protection system structures.

Effective thermal/mechanical properties of honeycomb core panels for hot structure applications

Abstract: The present work addresses the computation of the effective thermal and mechanical properties of a honeycombcore sandwich panel. The panel considered has a hexagon-cell honeycomb core. An alternative method, based on the Gebhart factors within a hexagonal cell, is presented in addition to the familiar Swann-Pittman method. The advantage of the alternative method is that it incorporates different emissivities for both face sheets and honeycomb and that it can easily be extended through this method with in-plane effective conductivity values for the honeycomb core. The effective mechanical properties of the core are determined using the mechanics of materials method. The effective continuum properties are then used with classical laminate theory to construct an equivalent laminate structure to replace the honeycomb-core sandwich panel. The thermal and thermomechanical behavior of the equivalent laminate structure is compared with that of the detailed model of the honeycomb-core sandwich panel using finite element analysis. The results of the study show that the proposed equivalent laminate structure accurately captures the thermal and thermomechanical behavior of the original honeycomb-core sandwich panel with very low computational costs. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Tie anchor and method for manufacturing insulated concrete sandwich panels

Abstract: A tie anchor for sandwich panels of reinforced concrete is formed as a flat strap The reinforced concrete sandwich panel is formed by placing a plurality of tie members vertically in the bottom of a horizontal form with reinforcing rods extending through holes in the ends of the ties adjacent to cross-feet A network or grid of reinforcing steel is supported from a chair provided by the ties and cross-feet and the concrete for the first layer of the panel is poured about the ties, cross-feet and reinforcing steel grid A layer of rigid insulation material is placed on top of the first layer of wet concrete about the projecting tie members immediately after pouring the first layer of concrete and a second grid of reinforcing steel rods is supported from the holes in the projecting upper ends of the tie members The second layer of concrete may be immediately poured about the upper end of the tie members and reinforcing steel The insulation material may occupy the entire area between the two concrete layers of the panel except for an 8-10 inch solid concrete section along the bottom edge of the panel connecting the layers

Composite honeycomb sandwich panel for fixed leading edges

Abstract: To virtually eliminate core crush in honeycomb sandwich structure for fixed leading edge panels, I rearrange the order of the plies. I use a full surface, facing ply of woven fabric impregnated with resin adjacent the core. This ply passes over an erosion strip at the part margin while lower plies terminate at the erosion strip. The facing ply is in contact with substantially the entire surface of the core along the entire skin-core interface to prevent slipping of the skin relative to the core during curing. I orient the facing ply 0/90.