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In this study, a novel theoretical approach based on high-order shear deformation theory is proposed to investigate the damping properties of honeycomb panels partially filled with foam. The assessment of damping properties in composite materials is accomplished through finite element theory, which elucidates the theoretical underpinnings for determining damping parameters specific to these materials. Subsequently, the damping parameters of the partially foam-filled honeycomb panel are determined based on the ratio of dissipated energy to strain energy. Ultimately, a comprehensive theoretical testing methodology is established, with tests conducted concurrently on composite materials to benchmark against data obtained via theoretical approaches. The findings underscore the capability of the proposed approach to assess the damping characteristics of diverse materials and extract their corresponding damping parameters. This method provides an effective theoretical model for investigating the damping characteristics in partially foam-filled fully composite honeycomb core sandwich structures. The model can also be applied to assess the damping properties of similar structures, offering practical guidance.

The object of the investigation is a honeycomb structure of composite sandwich made of glass-epoxy laminating layers and a honeycomb core of epoxy impregnated paper. Large composite tanks possessing cylindrical shape are produced using the winding process. Therefore, the final products have uneven thickness and fibre orientation lamina layers, and also an unevenly impregnated honeycomb layer. The aim of this research is to develop an economically attractive embedded ultrasonic measurement technique for on-field diagnostics of complex composite structures used for production of large liquid storage tanks. Development of the relatively cheap and easy to operate embedded diagnostic/monitoring technique is important aiming to assure safety of liquid storage tanks (monitoring structural integrity against overpressure, etc.) and detection of accidental defects that may appear during transportation, installation and exploitation of those structures. Typical defects that are aimed to be detected are relatively large delaminations/disbonds (area having diameter of 150–200 mm) of skin layers caused by low energy impacts that cannot be detected visually and show severe influence on the structural strength and safety of liquid tanks. This work presents results of numerical modeling and experimental research in low frequency (50 kHz) ultrasonic guided waves (UGW) propagation in large honeycomb composite structures. Finite element (FE) simulation of UGW propagation has been made aiming to reduce quantity of ultrasonic transducers and optimize their placement on composite structure. The possibilities to place ultrasonic transducers and receivers on both sides (internal or external) of composite structures and to use such a proposed technique for detection of delamination/debonding areas caused by low energy impacts or alternating semi static loads (e.g. filling and draining of liquid from storage tank) and monitoring of partial self-healing of relatively rigid composite structures were proved by experimental testing.

In this study, the instability regions of a honeycomb sandwich plate are investigated for different end conditions under periodic in-plane loading. The core layer of the sandwich plate is made of carbon nanotube (CNT)/glass fiber-reinforced honeycomb and the face layers of CNT/glass fiber- reinforced laminated composite. The governing equations are derived using classical laminated plate theory (CLPT) and solved numerically by using finite element formulation. The effectiveness of the developed finite element formulation is demonstrated by comparing the results in terms of natural frequencies with those available in the literature. The effects of CNT wt.% on the core material, CNT wt.% on the skin material, ply orientation and various end conditions on the variation of natural frequencies, loss factors and instability regions are studied. Finally, some inferences for the effects of CNT reinforcement on the honeycomb sandwich plate subjected to the periodic in-plane loads are discussed.

This article concerns with free vibration analysis of spinning sandwich cylindrical shells with functionally graded (FG) graphene/aluminum (Al) face sheets and honeycomb core exposed to an axial magnetic field. Lorentz magnetic force is derived by using Maxwell’s relations. The face layers are made of multi-nanocomposite sheets. Each sheet is composed of an Al matrix reinforced with graphene platelets (GPLs) that are uniformly distributed through the sheet thickness. The effective material properties of the face layers of the spinning sandwich cylindrical shells are derived employing the modified Halpin–Tsai model. The honeycomb core layer is made of hexagonal aluminum cells. According to the first-order shear deformation theory and Hamilton’s principle, five governing equations are obtained involving Lorentz force. Frequencies of the present model are analytically derived from the equations of motion. The present outcomes are examined by introducing some comparison examples. The effects of the geometric parameters, magnetic field parameter, GPLs weight fraction, core-to-face thickness ratio, circumferential wave number, axial wave number and spinning speed on the vibration of spinning sandwich honeycomb cylindrical shells are numerically discussed.

As energy carrier for the satellite and spacecraft, solar wings are related to the works of them. Thus, in the early design stage, the modal parameters of the solar wings are usually classified as the focus of the study. Compared several common substrate modeling methods and ideas, an equivalent model and an approximation method are proposed to analysis the floor and honeycomb core in existing solar wing substrates. The results indicate that it will be a good approximation to the honeycomb core model based on geometry by using the method of finite element modeling for anisotropic material equivalent honeycomb core.