Sandwich panel

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

Modeling of Sensor Placement Strategy for Shape Sensing and Structural Health Monitoring of a Wing-Shaped Sandwich Panel Using Inverse Finite Element Method

Abstract: This paper investigated the effect of sensor density and alignment for three-dimensional shape sensing of an airplane-wing-shaped thick panel subjected to three different loading conditions, i.e., bending, torsion, and membrane loads. For shape sensing analysis of the panel, the Inverse Finite Element Method (iFEM) was used together with the Refined Zigzag Theory (RZT), in order to enable accurate predictions for transverse deflection and through-the-thickness variation of interfacial displacements. In this study, the iFEM-RZT algorithm is implemented by utilizing a novel three-node C°-continuous inverse-shell element, known as i3-RZT. The discrete strain data is generated numerically through performing a high-fidelity finite element analysis on the wing-shaped panel. This numerical strain data represents experimental strain readings obtained from surface patched strain gauges or embedded fiber Bragg grating (FBG) sensors. Three different sensor placement configurations with varying density and alignment of strain data were examined and their corresponding displacement contours were compared with those of reference solutions. The results indicate that a sparse distribution of FBG sensors (uniaxial strain measurements), aligned in only the longitudinal direction, is sufficient for predicting accurate full-field membrane and bending responses (deformed shapes) of the panel, including a true zigzag representation of interfacial displacements. On the other hand, a sparse deployment of strain rosettes (triaxial strain measurements) is essentially enough to produce torsion shapes that are as accurate as those of predicted by a dense sensor placement configuration. Hence, the potential applicability and practical aspects of i3-RZT/iFEM methodology is proven for three-dimensional shape-sensing of future aerospace structures.

Thermal insulation for aircraft fuselage

Abstract: Thermal insulating apparatus for an aircraft fuselage of the type utilizing a sandwich panel construction. A foam insulation panel is provided which includes a plurality of standoffs for contacting the inwardly-facing skin of the sandwich panel. The standoffs may be arranged in a grid pattern, molded integrally with the rest of the panel, and bonded to the skin of the sandwich panel. The insulation panel may be used with or without a trim panel between it and the fuselage compartment, and in either case a sheet of metal foil may be attached to the inside face of the insulation panel. The foam may be of the self-skinning type so as to resist penetration of moisture into the foam panel and help direct condensate away from the fuselage compartment.

High-order free vibration analysis of sandwich plates with both functionally graded face sheets and functionally graded flexible core

Abstract: Free vibration analysis of functionally graded material sandwich plates is studied using a refined higher order sandwich panel theory A new type of FGM sandwich plates, namely, both functionally graded face sheets and functionally graded flexible core are considered The functionally graded material properties follow a power-law function The first order shear deformation theory is used for the face sheets and a 3D-elasticity solution of weak core is employed for the core On the basis of continuities of the displacements and transverse stresses at the interfaces of the face sheets and the core, equations of motion are obtained by using Hamilton’s principle The accuracy of the present approach is validated by comparing the analytical results obtained for a degradation model (functionally graded face sheets and homogeneous flexible core) with ones published in the literatures, as well as the numerical results obtained by finite element method and good agreements are reached Then, parametric study is conducted to investigate the effect of distribution of functionally graded material properties, thickness to side ratio on the vibration frequencies