The Experiment and Finite Element Analysis of Carbon Fiber Sandwich Beam With Pyramidal Truss Core Structure

Author(s):  
Jiguang Gu ◽  
Nana Yang ◽  
Zhanyi Guo ◽  
Xiongliang Yao

A new technology method is adapted to manufacture carbon fiber lattice sandwich beam with pyramidal truss core. The flat crush test experiment is to test the resistance to compression of the carbon fiber sandwich plate with pyramidal truss core. The result shows that after the pressure head contact the specimens adequately, and the stiffness of structure is the maximum. If the load is continuing increase, the pyramidal truss core may be destroyed, and both sides of the carbon fiber panel begin tottering. It emerges permanent deformation on the structures after an uninstall. The three-point bending test of lattice sandwich beam referred to ASTM C393-00 is designed to research the mechanical properties of face sheet and pyramidal truss core of lattice sandwich beam with theoretical analysis. Load-deflection curves of the middle of lattice sandwich beam in long span and in short span tests are retained, which are applied to obtain flexure stiffness of face sheet and shear strength of pyramidal truss core. It is found that span length has some influence on damage modes of lattice sandwich beam with pyramidal truss core. Debonding between face sheet and lattice core occurs when span is larger and core collapse appears when span is smaller. Crack expansion and fracture of resin base also both emerge in these two damage modes and the crack expansion consists of two different types which are crack expansion inside the resin base and crack expansion from the indenter to the support. Contrast with other lattice sandwich beam with similar or different shapes of core in the other references, the mechanical properties of this lattice sandwich beam by this new fabrication have obvious advantage at the same relative density.

2021 ◽  
pp. 109963622110288
Author(s):  
Yu-Zhou Wang ◽  
Li Ma

Recently, sandwich structures have been widely used in different fields because of their good mechanical properties, but these structures are weak in acoustic performance. In this paper, by combining pyramidal truss core sandwich structure with frame, a new structure is proposed with both good mechanical properties and excellent acoustic performance at low frequency. An analytical model of the pyramidal truss core sandwich structure with frame is developed to investigate the sound transmission loss (STL) performance. Finite element method (FEM) is also used to investigate the STL performance at low frequency. The effects of the incident wave angle and the geometrical parameters on the STL of the structure are discussed.


2015 ◽  
Vol 813 ◽  
pp. 278-284
Author(s):  
Bin Yang ◽  
Ji Feng Zhang ◽  
Lu Zhang ◽  
Shao Hua Fan ◽  
Li Min Zhou

Polymerized cyclic butylene terephthalate (pCBT) resin casts filled with short carbon fibers were prepared by the melt-mixing approach. The electrical conductivity of short-carbon-fiber (SCF) reinforced thermoplastic pCBT resin casts were investigated with a special attention paid to the properties in the percolation threshold region and the mechanical properties of the composites were also studied. The percolation threshold value of the novel material system was determined which was also verified by SEM images and the thermoelectric behavior of the specimens. Even though the electrical properties of SCF/pCBT composites enhanced significantly, the material becomes more brittle than neat pCBT and all the specimens appear brittle fracture during the mechanical test. Moreover, fiber pull-out is the main damage form in three-point-bending test.


2021 ◽  
Vol 7 ◽  
Author(s):  
Zhenkun Guo ◽  
Guobiao Hu ◽  
Jingchao Jiang ◽  
Liuding Yu ◽  
Xin Li ◽  
...  

3D printing (also known as additive manufacturing) has been developed for more than 30 years. The applications of 3D printing have been increasingly extended to a variety of engineering fields in recent years. The sandwich material with a high strength and overall low density is a kind of artificial material that has been extensively used in various industrial and daily life applications. This paper presents a comprehensive vibration analysis and passive control technique for a cantilevered sandwich beam with an hourglass lattice truss core fabricated with 3D printing technology. The governing equation of the beam is established by using a homogenized model and the Hamilton's principle, from which the natural frequencies are determined. The theoretical model is verified by the results from the existing literature and the finite element analysis. The frequency response of the sandwich beam measured experimentally further validates the proposed model. Subsequently, a non-linear energy sink (NES) is proposed for being employed to passively suppress the vibration of the sandwich beam. A parametric study based on the theoretical model confirms the viability of using NES to effectively control the vibration of the sandwich beam. This work presents a good demonstration of using 3D printing technology for fabricating sandwich beams with a complicated lattice core. More importantly, some guidelines regarding the dynamic analysis of sandwich beams are provided. In addition, the analytical method presented in this work provides a potential means to theoretically explore the advantages of using sandwich beams for energy harvesting in the future.


Mechanika ◽  
2019 ◽  
Vol 25 (5) ◽  
pp. 406-412
Author(s):  
Suleyman Kilic

Thanks to their low density and high strength, the 7XXX series aluminum alloys are widely used as a support/beam parts in the aerospace industry. This alloy is target in the lightening studies of the automotive industry and surveys for sheet metal are still in progress. It is a series of alloys that can be applied to the aging process and has the most effect on mechanical properties. As formability is quite weak, methods are investigated. In this study, tensile test, bending test and Erichsen tests are performed at different deformation rates and temperatures. As a result of the experiments, it has been seen that the formability increases at high temperature and low deformation rates. If paint baking time is long, there will be no loss of strength. Also, the bending process is modeled with the help of the finite element analysis programs and the springback estimations are examined. It is seen that the results of the modeling process are quite successful. The effect of the strain rate sensitivity is determined.


2021 ◽  
Vol 21 (4) ◽  
pp. 302-319
Author(s):  
Mahdi M. S. Shareef ◽  
Ahmed Naif Al-Khazraji ◽  
Samir Ali Amin

In this paper, functionally graded polymer hybrid nanocomposites have been produced by silica (SiO2) nanoparticles and alumina (Al2O3) nanoparticles distributed in a matrix of epoxy during the ultra-sonication via hand lay-up method. The variation in nanoparticles volume fraction (Vf.) has been given in the thickness direction for reaching the gradation. Each layer has a thickness of 1.2 mm through various concentrations of nanoparticles and is sequentially cast in acrylic moulds to fabricate the graded composite sheet with a 6 mm thickness. To fabricate the functionally graded layers, various concentrations of different nanoparticles (1.5% SiO2, 1% SiO2, epoxy, 2% Al2O3 and 3% Al2O3) have been used for tensile and compressive testing each isotropic layer of functionally graded material (FGM). The mechanical property that was studied for pure epoxy, isotropic and FGM was the flexural resistance. The flexural properties of FGM, isotropic nanocomposite (1% SiO2 + 2% Al2O3) and pristine epoxy, for evaluating their mechanical properties, including flexural stress-strain criteria and flexural Young's modulus, were determined via a Three-point bending test, with loading from the side of silica and alumina for the hybrid-FGM and at one side for the isotropic hybrid nanocomposite and pristine epoxy. The mechanical properties (tensile and compression) and the density of every layer were obtained for the epoxy resin and nanocomposites. They can benefit from the Finite Element Analysis (FEA) of the Three-point bending test via the Design Modeler (ANSYS workbench). The results of experiments were confirmed via building a detailed 3D FE model. Also, the advanced deformation results from the FE model were found in good agreement with the experimental outcomes.


Author(s):  
Xiongliang Yao ◽  
Wei Wang ◽  
Nana Yang ◽  
Zhanyi Guo

As a novel type of composite sandwich structure in recent years lattice structure with carbon fiber pyramidal truss core is applied to warship’s superstructure because of its high specific stiffness and specific strength, but it is difficult to design joint between superstructure and hull and there are few researches about the mechanical property of hybrid steel-to-lattice joint. Two kinds of hybrid joint specimens are designed and their compressive and flexural properties are investigated. The experimental results show that in compression test lattice sandwich is weakest and that debonding resulted from core macro-shear and face sheet wrinkling can lead to overall instability; bearing reaction can result in resin base fracture in lattice core and face sheet delamination is the main damage mode of joint structure in three-point bending test, which happens where stiffness mutation appears.


2015 ◽  
Vol 79 ◽  
pp. 311-321 ◽  
Author(s):  
Hongshuai Lei ◽  
Xiaolei Zhu ◽  
Haosen Chen ◽  
Hualin Fan ◽  
Mingji Chen ◽  
...  

2001 ◽  
Vol 123 (3) ◽  
pp. 322-328 ◽  
Author(s):  
Jianmei He ◽  
Martin Y. M. Chiang ◽  
Donald L. Hunston

A finite element analysis (FEA) was conducted to examine the feasibility of determining the shear modulus of an adhesive in a bonded geometry using a three-point bending test on a sandwich beam specimen. The FEA results were compared with the predictions from two analytical solutions for the geometry used to determine the impact of the assumptions that were made in these analyses. The analytical results showed significantly different to the values obtained from other experiments on bulk samples of the adhesive in the glassy region. Although there were some agreements in rubbery region, the negligible sensitivity of the beam stiffness to the presence of adhesive layer makes the agreements very questionable. To examine the possible explanations for these differences in glassy adhesives, sensitivity analysis was conducted to explore the effects of experimental variables. Some possible reasons for the differences are discussed, but none of these reasons taken alone satisfactorily account for the discrepancies. Until an explanation is found, the three-point bending test using a sandwich beam specimen to determine the adhesive shear modulus might not be a desirable test method, at least for the range of geometry examined in this study.


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