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Delamination Testing of AlSi10Mg sandwich structures with Pyramidal Lattice Truss Core made by Laser Powder Bed Fusion

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 51-62页

作者： M.Nuño J.Bühring M.N.Rao K.-U.Schröder Institute of Structural Mechanics and Lightweight Design RWTH Aachen UniversityWüllnerstraβe 752072 AachenGermany

sandwich structures possess a high bending stiffness compared to monolithic structures with a similar *** makes them very suitable for lightweight applications,where high stiffness to weight ratios are *** common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the ***,adhesive bonding is prone to delamination,a failure mode that is often difficult to *** paper presents the results of delamination testing of fully additive manufactured(AM)AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion(LPBF).The faces and struts are 0.5 mm thick,while the core is 2 mm *** inclination of the struts is 45°.To characterise the bonding strength,climbing drum peel tests and out-of-plane tensile tests are *** formulas are derived to predict the expected failure loads and *** analytics and tests are supported by finite element(FE)*** the analytic approach,design guidelines to avoid delamination in AM sandwich structures are *** study presents a critical face sheet thickness to strut diameter ratio for which the structure can *** ratio is mainly influenced by the inclination of the *** peel tests resulted in face yielding,which can also be inferred from the analytics and *** out-of-plane tensile tests didn’t damage the structure.

关键词： Additive Manufacturing sandwich structures Pyramidal Lattice Core

An Optimum Analysis Method of sandwich structures Made from Elastic-viscoelastic Materials

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Journal of Wuhan University of Technology(Materials Science) 2004年第2期19卷 76-78页

作者：陈应波 Wuhan University of Technology

Due to a viscoelastic damping middle layer,sandwich structures have the capacity of energy *** this paper,we describe the frequency-dependent property of viscoelastic materials using complex modulus model,and iterative modal strain energy method and iterative complex eigenvalue method are presented to obtain frequency and loss factor of sandwich *** two methods are effective and exact for the large-scale complex composite sandwich *** an optimum analysis method is suggested to apply to sandwich ***,as an example,an optimum analysis of a clamped-clamped sandwich beams is conducted,theoretical closed-form solution and numerical predictions are studied comparatively,and the results agree well.

关键词： optimum analysis viscoelastic materials sandwich structures complex modulus model loss factor

Additive Manufacturing of Continuous Fiber-Reinforced Polymer Composite sandwich structures with Multiscale Cellular Cores

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Chinese Journal of Mechanical Engineering(Additive Manufacturing Frontiers) 2023年第3期2卷 39-45页

作者： Zhenhu Wang Yaohui Wang Jian He Ke Dong Guoquan Zhang Wenhao Li Yi Xiong School of System Design and Intelligent Manufacturing Southern University of Science and TechnologyShenzhen518055China Ningbo Institute of Technology Beihang UniversityNingbo315832China

The use of composite sandwich structures with cellular cores is prevalent in lightweight designs owing to their superior energy-absorbing ***,current manufacturing processes,such as hot-press molding and mold pressing,require multiple steps and complex tools,thus limiting the exploration of advanced sandwich structure *** study reports a novel multi-material additive manufacturing(AM)process that allows the single-step production of continuous fiber-reinforced polymer composite(CFRPC)sandwich structures with multiscale cellular ***,the integration of CFRPC-AM and in situ foam AM processes provides effective and efficient fabrication of CFRPC panels and multiscale cellular cores with intricate *** cellular core design spans three levels:microcellular,unit-cell,and graded *** structures with a diverse set of unit-cell designs,that is,rhombus,square,honeycomb,and re-entrant honeycomb,were fabricated and their flexural behaviors were studied *** results showed that the sandwich structure with a rhombus core design possessed the highest flexural stiffness,strength,and specific energy *** addition,the effect of the unit-cell assembly on the flexural performance of the CFRP composite sandwich structure was *** proposed design and fabrication methods open new avenues for constructing novel and high-performance CFRPC structures with multiscale cellular cores that cannot be obtained using existing approaches.

关键词： Additive manufacturing sandwich structures Continuous fiber-reinforced composites Foam materials

High Temperature Effect on Absorption Coefficient of M-MPPs and sandwich structures Coupled with MPPs

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Open Journal of Acoustics 2020年第1期10卷 1-18页

作者： Daliwa Joseph Bainamndi Emmanuel Siryabe Serge Yamigno Doka Guy Edgar Ntamack Groupe de Mé canique des Mat&#233 riaux et Acoustique (GMMA) Universit&#233 de Ngaoundé ré Ngaound&#233 ré Cameroun Safran Helicopter Engines Groupe Evaluation Non Destructive Bordes France

This paper addresses the effect of high temperature on absorption performance of sandwich material coupled with microperforated panels (MPPs) in multiple configurations using a finite element model (FEM) over a frequency range from 10 to 3000 Hz. The structure is backed with a rigid wall which can either be Aluminium or Al-Alloy used in aeronautic or automobile. The wave propagation in porous media is addressed using Johnson Champoux Allard model (JCA). The FEM model developed using COMSOL Multiphysics software makes it possible to predict the acoustic absorption coefficient in multilayer microperforated panels (M-MPPs) and sandwich structure. It is shown that, when structures made by MPPs or sandwich materials are submitted to high temperature, the absorption performance of the structure is strongly modified in terms of amplitude and width of the bandgap. For application in sever environment (noise reduction in engines aircrafts), Temperature is one of the parameters that will most influence the absorption performance of the structure. However, for application in the temperature domain smaller than 50?C (automotive applications for example), the effect of temperature is not significant on absorption performance of the structure.

关键词： Absorption Coefficient Finite Element Model Microperforated Plates Poroelastic Core sandwich structures

Thermoelastic Stress Analysis of Aged sandwich structures

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Thermoelastic Stress Analysis of Aged Sandwich Structures

Design,fabrication,and dynamic mechanical responses of fiber-reinforced composite lattice materials

第十三届国际复合材料会议

作者： J.S.Earl J.M.Dulieu-Barton R.A.Shenoi School of Engineering Sciences University of Southampton Highfield Southampton SO 17 1BJ School of Engineering Sciences University of Southampton Highfield Southampton SO 17 1BJ School of Engineering Sciences University of Southampton Highfield Southampton SO 17 1BJ

＜正＞The aim of this paper is to use the thermoelastic stress analysis （TSA） technique to determine the load transfer mechanisms in sandwich construction tee joints, which have been environmentally aged, and to assess how their performance has changed with respect to the unaged case. An extensive literature review has shown that although a wealth of information exists on the long-term performance of FRP materials exposed to hygrothermal environments, the behaviour of aged composite sandwich structures has not been addressed. The purpose of this work is to begin to fill this void.

关键词： TSA deltatherm sandwich structures hygrothermal exposure ageing

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International Journal of Mechanical System Dynamics 2023年第3期3卷 213-228页

作者： Jian Xiong Cheng Gong Qianqian Wu Li Ma Jinshui Yang Linzhi Wu Center for Composite Materials and structures Harbin Institute of TechnologyHarbinChina National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbinChina

Fiber-reinforced composites are a popular lightweight materials used in a variety of engineering applications,such as aerospace,architecture,automotive,and marine construction,due to their attractive mechanical *** lattice materials from fiber-reinforced composites is an efficient approach for developing ultra-lightweight structural systems with superior mechanical proper-ties and multifunctional *** contrast to corrugated,foam,and honeycomb core materials,composite lattice materials can be manufactured with various architectural designs,such as woven,grid,and truss ***,lattice materials with open-cell topology provide multifunctional advantages over conventional closed-cell honeycomb and foam structures and are thus highly desirable for developing aerospace systems,hypersonic vehicles,long-range rockets and missiles,ship and naval structures,and protective *** objective of this study is to review and analyze dynamic mechanical behavior performed by different researchers in the area of composite lattice materials and to highlight topics for future research.

关键词： fiber-reinforced composite lattice structures sandwich structures dynamic mechanical behavior

New advances in fiber-reinforced composite honeycomb materials

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Science China(Technological Sciences) 2020年第8期63卷 1348-1370页

作者： WEI XingYu XIONG Jian WANG Jie XU Wu Center for Composite Materials and structures Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbin 150080China Shanghai Aircraft Design and Research Institute Shanghai 201210China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China

In sandwich structures,lightweight cellular materials as the core hold the face sheets far away from the neutral axis to maximize the bending performance of the *** materials as a major type of lightweight cellular materials have been widely applied in various fields,including aerospace,vehicle,marine,architecture and mechanical engineering,due to reliable mechanical properties and excellent *** fiber-reinforced composites is an efficient method to develop ultralight honeycomb materials with superior mechanical *** recent years,fiber-reinforced composite honeycomb materials possessing lightweight and excellent mechanical performances have attracted noticeable attention to replacing traditional aluminum honeycombs and Nomex *** to metal,polymer and Nomex paper,fiber-reinforced composites possess various merits,such as high specific stiffness and specific strength,excellent fatigue property,corrosion resistance and high-temperature ***,the applications of fiber-reinforced honeycomb material for sandwich core have unlimited potential in hypersonic vehicles,long-range rockets,cargo vessels and protective *** the fact that attention has been rapidly increasing,there is a lack of comprehensive reviews of new advances in the field of fiber-reinforced composite honeycomb *** this review,new advances reported by different scientists in the field of fiber-reinforced honeycomb materials have been reviewed and analyzed to provide an in-depth overview and knowledge for beginners in the field of ultralightweight and high-performance composite sandwich *** challenges and prospects for the development of fiberreinforced honeycomb materials have also been presented.

关键词： composite honeycomb materials sandwich structures failure mechanism mechanical property

ON RESIDUAL COMPRESSIVE STRENGTH PREDICTION OF COMPOSITE sandwich PANELS AFTER LOW-VELOCITY IMPACT DAMAGE

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Acta Mechanica Solida Sinica 2006年第1期19卷 9-17页

作者： Xie Zonghong Anthony J. Vizzini Tang Qingru College of Astronautics Northwestern Polytechnical University Xi＇an 710072 China Department of Aerospace Engineering Mississippi State University MS 39762 USA Aviation Engineering Institute Civil Aviation Flight University of China Guanghan 618307 China

This paper introduces a nonlinear finite element analysis on damage propagation behavior of composite sandwich panels under in-plane uniaxial quasi-static compression after a low velocity impact. The major damage modes due to the impact, including the residual indentation on the impacted facesheet, the initially crushed core under the impacted area, and the delamination are incorporated into the model. A consequential core crushing mechanism is incorporated into the analysis by using an element deactivation technique. Damage propagation behavior, which corresponds to those observed in sandwich compression after impact （SCAI） tests, has been successfully captured in the numerical simulation. The critical far field stress corresponding to the onset of damage propagation at specified critical locations near the damage zone are captured successfully. They show a good correlation with experimental data. These values can be used to effectively predict the residual compressive strength of low-velocity impact damaged composite sandwich panels.

关键词： sandwich structures impact delamination damage growth honeycomb core finite element method

Optimal distribution of active piezoelectric elements for noise attenuation in sandwich panels

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International Journal of Smart and Nano Materials 2020年第4期11卷 400-416页

作者： J.F.A.Madeira A.L.Araujo IDMEC Instituto Superior TecnicoUniversidade de LisboaLisboaPortugal ADM ISELInstituto Politecnico de LisboaLisboaPortugal

In this paper,a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actua-tors for noise attenuation in sandwich panels is *** noise attenuation is achieved by using negative velocity feedback control with co-located sensors and *** control gains are also optimized in order to obtain the most efficient noise attenuation in a given frequency *** in-house implementation of a viscoelastic soft core sandwich plate finite element,including surface-bonded piezoelectric sensors and actuators with active control capabilities,is used for obtaining the frequency response of the *** sound transmission capability of the panels is evaluated using the radiated sound power,along with the Rayleigh integral approach,which is suitable for lightly coupled structural/acoustic *** Direct MultiSearch(DMS)optimization algorithm is used to minimize the added weight due to the piezoelectric material,minimizing also the number of required controllers and maximizing the noise *** total length of the radiated sound power curve is shown to be an effective measure of noise attenuation in a given frequency ***-off Pareto fronts and the obtained optimal configurations are presented and discussed.

关键词： sandwich structures piezoelectricity viscoelasticity active damping multiobjective optimization