Papers by Keyword: Sandwich Panel

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Authors: Qi Chao Xue, Guang Ping Zou
Abstract: A method of fatigue damage analysis for sandwich panels on ship is studied in this paper. When ship is navigating on the sea, the waves that ship encounters can be regarded as a stochastic process. And responses of ship movement can also be regarded as a series of stochastic spectrums. By using of finite element method, loads spectrums of inner ship structures in different sea conditions can be obtained. Then short term or long term distribution of stress range can be determined. Residual stiffness modal is used to describe the damage of sandwich panels under fatigue loads. And fatigue damage variable D is defined based on stiffness degration. An integral equation to calculate fatigue damage under loads spectrum is constructed to describe the damage of ship sandwich structure in long term and short term stress spectrum distributions.
Authors: Sang Woo Kim, Dae Yong Kim
Abstract: Metallic sandwich panels based on lattice truss structure have been developed for a wide range of potential applications with their lightweight and multi-functionality. The study focused on the analytical approach to investigate compression and shear characteristics of pyramidal and tetrahedral truss unit cells. With various unit cell models which have the same weight per unit area but different member angle, analytical solutions for effective stiffness and strength have been predicted and compared with each other. The results showed that there are the most optimal core configuration to maximize effective mechanical properties.
Authors: Ke Wei Ding, Gang Wang, Wan Yun Yin
Abstract: As a new constructional material, composite sandwich panels are applied in engineering more often than ever. This paper focuses on the structure and foreign research status of sandwich panels which are used in practical engineering problems that need attention. The structure of the composition of the sandwich panel, force characteristics and analysis methods, a set of load-bearing thermal insulation, sound insulation and decoration in one of the new sandwich insulation composite wall form, can comprehensively address architectural, structural safety, and contradict the thermal insulation performance and durability problem. Thus they can be better applied to the engineering practice and meet the development requirement of building energy-saving and adaptation of housing industrialization.
Authors: Bai Song Du, Zhong Guo Ma, Ling Luo
Abstract: The paper is concerned with using experiments and numerical simulations to study the mechanical performance of a Honeycomb Fiber-Reinforced Polymer (HFRP) sandwich panel at different temperatures, especially at low temperatures coupled with cyclic loadings. All physical tests were performed in a temperature controlled room and used a three-point bending setup where the applied load gradually increased from zero to 36kN. Experimental results show that the stiffness of the panel becomes softer at some lower temperatures. In order to eliminate the influence of the initial conditions, an incremental method was introduced to process the experimental results. This method treated all displacements and strains as zero when applying a load of 4.5kN. Furthermore, the change in stiffness of the panel was obtained through the use of a special equivalent stiffness which involved measuring the change of the stiffness of the panel. After comparing different methods, the composite shell method was used to build finite element models for numerical simulations in ABAQUS. Reduction of moduli and Random Mesh Size Method (RMSM) were employed to simulate microcracking between fibers and matrix and debonding between the core and face sheets, respectively.
Authors: Bai Song Du, Zhong Guo Ma, Ling Luo
Abstract: The companion paper presents experimental results and numerical simulation methods to illustrate the behavior of FRP sandwich panels under synergistic effects of low temperature and cyclic loading. This paper aims at verifying the proposed simulation methods and providing several examples of its application to FRP sandwich panels. In this regard, four categories were simulated including: perfect bonding, microcracks, debonding Case I, and debonding Case II. Each category contained six ABAQUS models with two types of loads, thermal loads and applied mechanical loads. Results showed that microcracking would lower the stiffness of the panel, but not as much as debonding between the core and the face sheets.
Authors: Wei Dong Shen, Sheng Chun Wang, Jian Li Wang, Jia Feng Xu, Si Hong Song
Abstract: A simple approach to reduce the governing equations for thick honeycomb sandwich panels to a single equation containing only one displacement function is proposed in this article. The variational equations of motion are derived using Hamilton’s principle and by introducing differential operators. The exact solution of the natural frequencies for rectangular honeycomb sandwich panels with all edges simply-supported is obtained and leading to a satisfied agreement with theoretical results. The influence of the ratio of core thickness to face sheet thickness and aspect ratio on the natural frequencies is studied. The analysis results demonstrate that the presence of inertia of rotation will decrease natural frequencies, and the aspect ration changes not only the value of natural frequencies of the sandwich panel but also the mode order.
Authors: Jong Woong Lee, Cheol Won Kong, Se Won Eun, Jae Sung Park, Young Soon Jang, Yeong Moo Yi, Gwang Rae Cho
Abstract: Composite materials are used in aerospace structures due to their considerable bending stiffness and strength-to-weight ratio. A composite sandwich is composed of a face-sheet and an aluminum core. The face-sheet of the sandwich takes the bending stress and core of sandwich takes the shear stress. A compression test and FEM analysis accomplished about composite sandwich panels that have curvature. The FEM analysis was performed using a commercial code, ANSYS and the compression test was performed until failure occurred in the sandwich panel. A strain gauge and a displacement gauge were used to acquire the data. In this paper, the failure strength and failure mode was checked. Additionally, the results of the test and analysis were compared.
Authors: Yan Chang Zhang, Shi Lian Zhang, Zi Li Wang
Abstract: The out-of-plane quasi-static compressive behavior of four types of corrugated cores (V-type, U-type, X-type and Y-type core) has been investigated by experiment and FE simulations. By transient dynamic finite element analysis code MSC.Dytran numerical simulations were performed for calculating crushing forces, deformation mode and energy absorption. The FE simulations predict the crush behavior of cores with reasonable accuracy and provide the whole progressive buckling process and deformation modes. Experiment and simulation indicate that the U-type core, V-type core and X-type core structures show excellent crushing resistance performance and energy absorption characteristic. The crush performance of the Y-type core structures is relatively poor because of bending mode.
Authors: Amir Refahi Oskouei, Milad Hajikhani, Mehdi Ahmadi Najaf Abadi, Amir Sharifi, Mohammad Heidari
Abstract: This paper addresses damage evaluation of loaded sandwich panels by using acoustic emission (AE) as a non-destructive method. The specimens were loaded monotonically out-of-plane in control of displacement and the tests were stopped at three different damage levels. Each loading level activates different failure mechanism that can influence on residual strength of material. After each quasi-static test, the damaged plate was cut by a diamond saw to obtain tensile specimens. After cutting, compression test carried out by using acoustic emission to monitor the process. Depend on loading level the damage value was variant as it caused different residual strength that was related to acoustic emission signals activities. There is a relation between AE signal energy and mechanical energy that can follow to evaluate the residual strength of panels in different loading level in sandwich panels. Results show that the using AE method having mechanical results can be effective in residual strength and progressive damage evolution.
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