scholarly journals Pembuatan dan Pengujian Panel Honeycomb Sandwich dengan Inti Berbentuk Gelombang Berbahan Komposit Serat Bambu

2021 ◽  
Vol 5 (2) ◽  
pp. 165-177
Author(s):  
Marsono Marsono ◽  
Sarah Fauziyyah Hanifa ◽  
Faizal Akbar

ABSTRAKDalam penelitian ini, komposit serat bambu dibuat menjadi panel struktur honeycomb sandwich dan diuji untuk mengukur kemungkinan pemanfaatannya sebagai bahan untuk membuat sudu turbin angin sumbu vertical. Honeycomb sanwich serat bambu yang dibuat memiliki inti (core) yang berbentuk gelombang sinus pada arah memanjang panel. Sebagai pengikat pada komposit ini digunakan resin polyester. Panel honeycomb sandwich yang dibuat memiliki panjang 500mm dan lebar 200mm, sedangkan tebal panel dibuat dengan  dua variasi, yaitu dengan tinggi inti honeycomb 12mm dan  17mm. Panel honeycomb sandwich ini diuji dengan uji bending untuk mendapatkan angka kekuatan lentur (flexural strength) dan angka kekakuan (stiffness). Dari tiga panel yang dibuat identik untuk masih-masing ketinggian inti honeycomb, diperoleh angka kekuatan lentur dan kekakuan terbesar pada panel dengan ketinggian inti honeycomb17mm, yaitu dengan angka kekuatan lentur 0,91kg/mm2 dan angka kekakuan 11,35kg/mmKata kunci: honeycomb sandwich, komposit serat bambu,gelombang sinus,kekuatan lentur, kekakuan.  ABSTRACTIn this research, bamboo fiber composite are made into honeycomb sandwich structure panel and to be tested for its ability as a material for vertical axis wind turbine blades. Bamboo fiber honeycomb sandwich had a sinusoidal-shaped core in the longitudinal direction of the panel. Polyester resin was used as a binder on this composite. The honeycomb panels that have been made have a length of 500mm and a width of 200mm. The thickness of the panels was made of two variations, which was has 12mm and 17mm honeycomb core-height. The honeycomb sandwich panel was tested by bending test to obtain flexural strength and stiffness. From the three panels that have been made in identical dimension for each honeycomb core-height, the highest flexural strength and stiffness was obtained in the specimen with the honeycomb core-height of 17mm, with a flexural strength of 0,91kg/mm2 and astiffness of 11,35kg/mm. Keywords: honeycomb sandwich, bamboo fiber composite, sinusoidal wave,  flexurall strength, stiffness.

2014 ◽  
Vol 59 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. Arbaoui ◽  
Y. Schmitt ◽  
J.-L. Pierrot ◽  
F.-X. Royer

Abstract Sandwich structures are widely used in lightweight construction especially in aerospace industries because of their high specific strength and stiffness. This paper investigates the effect of core thickness and intermediate layers on the mechanical properties of a polypropylene honeycomb core/composite facing multilayer sandwich structure under three points bending. We developed a theoretical model which makes it possible to calculate the shear properties in multi-cores. The results obtained by this model are agreed with our experimental results, and the results obtained with bending test showed that the mechanical properties of the composite multilayer structures increase with core thickness and intermediate layers.


Author(s):  
Yue Liu ◽  
Weicheng Gao ◽  
Wei Liu ◽  
Zhou Hua

This paper presents an investigation on the mechanical response of the Nomex honeycomb core subjected to flatwise compressive loading. Thin plate elastic in-plane compressive buckling theory is used to analyze the Nomex honeycomb core cell wall. A mesoscopic finite element (FE) model of honeycomb sandwich structure with the Nomex honeycomb cell walls is established by employing ABAQUS/Explicit shell elements. The compressive strength and compressive stiffness of Nomex honeycomb core with different heights and thickness of cell walls, i.e. double cell walls and single cell walls, are analyzed numerically using the FE model. Flatwise compressive tests are also carried out on bare honeycomb cores to validate the numerical method. The results suggest that the compressive strength and compression stiffness are related to the geometric dimensions of the honeycomb core. The Nomex honeycomb core with a height of 6 mm has a higher strength than that of 8 mm. In addition, the honeycomb core with lower height possesses stronger anti-instability ability, including the compressive strength and stiffness. The proposed mesoscopic model can effectively simulate the crushing process of Nomex honeycomb core and accurately predict the strength and stiffness of honeycomb sandwich panels. Our work is instructive to the practical applications in engineering.


2019 ◽  
Vol 821 ◽  
pp. 465-471 ◽  
Author(s):  
Siew Choo Chin ◽  
Jacky Neing Sheng Moh ◽  
Shu Ing Doh ◽  
Fadzil Mat Yahaya ◽  
Jolius Gimbun

Fiber reinforced polymer (FRP) is widely used in the construction industry for structural strengthening due to their outstanding mechanical properties. However, the production of synthetic fibers such as FRP is detrimental to the environment. Alternatively, natural fiber composite may be used as external strengthening material. This paper presents the potential of bamboo fiber composite plate (BFCP) to strengthen the reinforced concrete (RC) beams in flexure. The bamboo of species Dendrocalamus asper was used to produce the fiber and fiber-to-volume ratio was set at 2:5. The composite plate was fabricated by binding bamboo fibers with epoxy using a hand-lay-up method. The flexural and tensile strength of the BFCP was measured and all the beams were tested to failure under four-point bending test. It was found that BFCP exhibited a higher flexural and tensile strength compared to pure epoxy samples. Meanwhile, the RC beams strengthened using BFCP exhibited an increment of 10-12% in beam structural capacity compared to the un-strengthened beams. Bonding of BFCP in the flexure zone was able to divert the vertical cracks into diagonal at the edge of the composite plate. Findings from this work may serve as a useful guide to strengthen RC beams using a BFCP.


2019 ◽  
Vol 3 (2) ◽  
Author(s):  
Marsono Marsono ◽  
Ali Ali ◽  
Nico Luwis

ABSTRAKRekayasa struktur honeycomb sandwich dalam pengembangan material banyak telah dimanfaatkan karena memiliki kekuatan struktur yang relatif tinggi dengan bobot material yang ringan. Material dengan rekayasa struktur honeycomb cocok digunakan pada mobil hemat energi, untuk meningkatkan efesiensi energi. Dalam penelitian ini dibuat panel honeycomb sandwich berbahan komposit serat kaca (fibreglass) dan matirks resin. Panel ini nantinya akan diterapkan pada rangka kendaraan hemat energi. Tiga panel honeycomb sandwich dibuat dengan variasi pada ketebalan dinding sel terutama ditujukan untuk mengetahui pengaruh ketebalan dinding sel terhadap kekuatan dan kekakuan panel honeycomb sandwich. Variasi ketebalan dinding sel didapatkan dari variasi penerapan jumlah lapisan fiberglass pada dinding sel honeycomb, yaitu 2 lapis, 4 lapis dan 6 lapis fibreglass. Hasil pengujian bending menunjukkan bahwa panel honeycomb sandwich dengan ketebalan dinding sel terbesar, yaitu dengan 6 lapisan fibreglass, memberikan kekuatan lentur terbesar yaitu 3,774 kg/mm2, dan kekakuan tertinggi, yaitu 21,48 kg/mm.Kata kunci: honeycomb sandwich, komposit fibreglass, kekuatan lentur, kekakuan.  ABSTRACTEngineering of honeycomb sandwich structure in the materials development has been highly utilized because of its high structural strength with lightweight material. Honeycomb structure material is suitable for use in energy-efficient cars, to increase energy efficiency. In this research, sandwich honeycomb panel were made from fibreglass composite with resin as matrices. This panel will be applied to the frame of energy-efficient vehicle. Three sandwich honeycomb panels were made with variations in cell wall thickness. These variations are primarily intended to determine the effect of cell wall thickness to the flexural strength and stiffness of the honeycomb sandwich panel. Variations in cell wall thickness were obtained from variations in the application of fibreglass layers on honeycomb cell walls, which are 2 layers, 4 layers and 6 layers of fibreglass. The bending test results show that the honeycomb sandwich panel with the largest cell wall thickness, which has 6 layers of fibreglass, provides the greatest flexural strength of 3.774 kg/mm2, and the highest stiffness of 21.48 kg/mm.Keywords: honeycomb sandwich,fibreglass composite , flexurall strength, stiffness.


2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Marsono Marsono ◽  
Ali Ali ◽  
Alek P. Sembiring

ABSTRAKPerubahan bentuk dan dimensi sudu akan menurunkan kinerja turbin angin. Perubahan bentuk dan dimensi sudu sangat dipengaruhi oleh kekakuan dan kekuatan sudu turbin tersebut. Pada kasus di lapangan, ditemui bahwa sudu turbin angin sumbu vertikal yang dibuat dengan bahan komposit serat karbon ternyata tidak memiliki kekakuan yang baik jika hanya dibuat dengan satu lapis (layer) serat karbon. Untuk mengatasi masalah kekakuan ini, maka dilakukan penambahan tulang penguat (stiffener rib) dari bahan yang sama pada sudu turbin angin. Pengujian yang telah dilakukan menunjukan bahwa penambahan tulang penguat pada sudu turbin angin sumbu vertikal telah menambah kekakuan sudu secara signifikan yang cenderung mengikuti grafik eksponensial. Kekakuan (K) sudu dengan tinggi tulang 6 mm adalah 0,0258 kg/mm. Kekakuan sudu dengan tinggi tulang 9 mm adalah 0,0740 kg/mm. Kekakuan sudu dengan tinggi tulang 12 mm adalah 0,2250 kg/mm. Di sisi lain, kekuatan lentur sudu turbin juga meningkat. Dengan penambahan tulang 6mm, kekuatan lentur maksimum (􀀀max) mencapai 4,008 kg/mm2, dengan penambahan tulang 9 mm kekuatan lentur mencapai 4,145 kg/mm2, dengan penambahan tulang 12 mm kekuatan lentur mencapai 4,544 kg/mm2.Kata kunci: sudu turbin angin sumbu vertikal, inersia penampang, kekakuan, kekuatan lentur.ABSTRACTChanges in shape and dimension of the blade will decrease the wind turbine performance. These change are strongly influenced by the stiffness and strength of turbine blade. It was found that vertical axis wind turbine blades which is made with carbon fiber composite did not have good stiffness if it was made with only one layer of carbon fiber. To overcome this stiffness problem, stiffener rib with the same material was applied on wind turbine blade. The test that has been done shows that the addition of the stifferner rib to the vertical axis wind turbine blade has significantly increased the stiffness that tends to follow the exponential graphic. The stiffness (K) of the blade with 6 mm rib height is 0.0258 kg/mm. The blade stiffness with 9 mm rib height is 0.0740 kg/mm. The blade stiffness with 12 mm rib height is 0.2250 kg/mm. On the other hand, the bending strength of the turbine blade is also increased. With the addition of 6mm rib, the maximum flexurall strength (smax) reaches 4,008 kg/mm2. With the addition of 9 mm rib, the strength reaches 4,145 kg/mm2. With the addition of 12 mm rib, the strength reaches 4,544 kg/mm2.Keywords: vertical axis wind turbine, inertia, stiffness, flexurall strength.


2010 ◽  
Vol 123-125 ◽  
pp. 1135-1138 ◽  
Author(s):  
Yeon Hee Lee ◽  
Hitoshi Takagi ◽  
Kazuya Ohkita ◽  
Han Ki Yoon

. This paper deals with the mechanical characterization of short bamboo fiber reinforced green composites (BFGC). The effects of thermal shock on the mechanical properties of BFGC were investigated. Their flexural strength was evaluated by 3-point bending test, and Vickers hardness and elastic modulus were evaluated by a nano-indentation method. The fracture surfaces and microstructure of BFGC were examined by SEM. The results of evaluated mechanical properties (3-point bending test) after thermal shock indicated that the strength of BFGC decreased below 40°C, however the strength became constant above 40°C. The Vickers hardness and modulus of elasticity evaluated from the nano-indentation tests also represented a similar trend to that of flexural strength. The fracture surface of thermal shocked BFGC after bending tests indicated the pull-outed bamboo fibers. This might be responsible for insufficient bonding between bamboo fiber and resin.


2021 ◽  
pp. 152808372110003
Author(s):  
M Atta ◽  
A Abu-Sinna ◽  
S Mousa ◽  
HEM Sallam ◽  
AA Abd-Elhady

The bending test is one of the most important tests that demonstrates the advantages of functional gradient (FGM) materials, thanks to the stress gradient across the specimen depth. In this research, the flexural response of functionally graded polymeric composite material (FGM) is investigated both experimentally and numerically. Fabricated by a hand lay-up manufacturing technique, the unidirectional glass fiber reinforced epoxy composite composed of ten layers is used in the present investigation. A 3-D finite element simulation is used to predict the flexural strength based on Hashin’s failure criterion. To produce ten layers of FGM beams with different patterns, the fiber volume fraction ( Vf%) ranges from 10% to 50%. A comparison between FGM beams and conventional composite beams having the same average Vf% is made. The experimental results show that the failure of the FGM beams under three points bending loading (3PB) test is initiated from the tensioned layers, and spread to the upper layer. The spreading is followed by delamination accompanied by shear failures. Finally, the FGM beams fail due to crushing in the compression zone. Furthermore, the delamination failure between the layers has a major effect on the rapidity of the final failure of the FGM beams. The present numerical results show that the gradient pattern of FGM beams is a critical parameter for improving their flexural behavior. Otherwise, Vf% of the outer layers of the FGM beams, i.e. Vf% = 30, 40, or 50%, is responsible for improving their flexural strength.


2021 ◽  
Vol 5 (6) ◽  
pp. 144
Author(s):  
Klaudio Bari ◽  
Thozhuvur Govindaraman Loganathan

The research aim is to investigate the performance of novel enriched mineral fibres (Filava) in polysiloxane SLIRES H62 resin. Specimens were manufactured using a vacuum bagging process and oven cured at 250 °C. Specimens were prepared for flexural testing according to BS EN ISO 14125:1998 to obtain flexural strength, modulus, and elongation. The mechanical strength was compared to similar composites, with the aim of determining composite performance index. The flexural modulus (9.7 GPa), flexural strength (83 MPa), and flexural strain (2.9%) were obtained from a three-point bending test. In addition, the study investigates the thermal properties of the composite using a state-of-art Zwick Roell high temperature tensile rig. The results showed Filava/Polysiloxane Composites had an ultimate tensile strength 400 MPa, Young’s modulus 16 GPa and strain 2.5% at 1000 °C, and no smoke and ash were observed during pyrolysis. Ongoing research is currently taking place to use Filava-H62 in fire-retardant enclosure for lithium-ferro-phosphate Batteries used in electric trucks.


2013 ◽  
Vol 486 ◽  
pp. 283-288
Author(s):  
Ladislav Fojtl ◽  
Soňa Rusnáková ◽  
Milan Žaludek

This research paper deals with an investigation of the influence of honeycomb core compression on the mechanical properties of sandwich structures. These structures consist of prepreg facing layers and two different material types of honeycomb and are produced by modified compression molding called Crush-Core technology. Produced structures are mechanically tested in three-point bending test and subjected to low-velocity impact and Charpy impact test.


2015 ◽  
Vol 787 ◽  
pp. 250-254 ◽  
Author(s):  
T. Micha Premkumar ◽  
Sivamani Seralathan ◽  
T. Mohan ◽  
N.N.P. Saran Reddy

This is Part-1 of the two-part paper in considering the effect of cambered airfoil blades on self-starting of vertical axis wind turbine. Part 1 reports the numerical studies on self-starting of vertical axis wind turbine with comparative studies involving NACA 0012 and cambered airfoil NACA 4415. Part 2 of the paper deals with numerical studies of NACA 0018 and cambered air foil NACA 63415. Darrieus type VAWT is attracting many researchers attention for its inherent advantages and its diversified applications. However, a disadvantage is when the rotor is stationary, no net rotational forces arises, even at high-wind speed. The principal advantage of the vertical axis format is their ability to accept wind from any direction without yawing mechanism. However, self-starting capability is the major drawbacks. Moreover, literatures based on computational analysis involving the cambered airfoil are few only. The objective of this present study is to select the suitable airfoil blades on self-starting of VAWT at low-Reynolds number. The numerical studies are carried out to identify self-starting capability of the airfoil using CFD analysis by studying the flow field over the vertical axis wind turbine blades. The commercial CFD code, ANSYS CFX 13.0© was used for the present studies. Initially, the flow over NACA 0012 was simulated and analyzed for different angles of attacks and similarly carried out for NACA 4415. The contours of static pressure distribution and velocity as well as the force and torque were obtained. Even though the lift force for cambered airfoil NACA 4415 is higher, based on the torque values of the above blade profiles, asymmetrical airfoil NACA 0012 is found to be appropriate for self-starring of VAWT.


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