Process-controlled optimization of the tensile strength of bamboo fiber composites for structural applications

2014 ◽  
Vol 67 ◽  
pp. 125-131 ◽  
Author(s):  
Dirk E. Hebel ◽  
Alireza Javadian ◽  
Felix Heisel ◽  
Karsten Schlesier ◽  
Dragan Griebel ◽  
...  
Author(s):  
Jerachard Kaima ◽  
Itthichai Preechawuttipong ◽  
Pawarut Jongchansitto ◽  
Nattaphat Charoenloe

2021 ◽  
Vol 5 (4) ◽  
pp. 100
Author(s):  
Anjum Saleem ◽  
Luisa Medina ◽  
Mikael Skrifvars

New technologies in the automotive industry require lightweight, environment-friendly, and mechanically strong materials. Bast fibers such as kenaf, flax, and hemp reinforced polymers are frequently used composites in semi-structural applications in industry. However, the low mechanical properties of bast fibers limit the applications of these composites in structural applications. The work presented here aims to enhance the mechanical property profile of bast fiber reinforced acrylic-based polyester resin composites by hybridization with basalt fibers. The hybridization was studied in three resin forms, solution, dispersion, and a mixture of solution and dispersion resin forms. The composites were prepared by established processing methods such as carding, resin impregnation, and compression molding. The composites were characterized for their mechanical (tensile, flexural, and Charpy impact strength), thermal, and morphological properties. The mechanical performance of hybrid bast/basalt fiber composites was significantly improved compared to their respective bast fiber composites. For hybrid composites, the specific flexural modulus and strength were on an average about 21 and 19% higher, specific tensile modulus and strength about 31 and 16% higher, respectively, and the specific impact energy was 13% higher than bast fiber reinforced composites. The statistical significance of the results was analyzed using one-way analysis of variance.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1198
Author(s):  
Yu’an Hu ◽  
Mei He ◽  
Kate Semple ◽  
Meiling Chen ◽  
Hugo Pineda ◽  
...  

Bamboo fiber composite (BFC) is a unidirectional and continuous bamboo fiber composite manufactured by consolidation and gluing of flattened, partially separated bamboo culm strips into thick and dense panels. The composite mechanical properties are primarily influenced by panel density, its variation and uniformity. This paper characterized the horizontal density distribution (HDD) within BFC panels and its controlling factors. It revealed that HDD follows a normal distribution, with its standard deviation (SD) strongly affected by sampling specimen size, panel thickness and panel locations. SD was lowest in the thickest (40 mm) panel and largest-size (150 × 150-mm2) specimens. There was also a systematic variation along the length of the BFC due to the tapering effect of bamboo culm thickness. Density was higher along panel edges due to restraint from the mold edges during hot pressing. The manual BFC mat forming process is presented and found to effectively minimize the density variation compared to machine-formed wood composites. This study provides a basic understanding of and a quality control guide to the formation uniformity of BFC products.


Author(s):  
Faris M. AL-Oqla

The available potential plant waste could be worthy material to strengthen polymers to make sustainable products and structural components. Therefore, modeling the natural fiber polymeric-based composites is currently required to reveal the mechanical performance of such polymeric green composites for various green products. This work numerically investigates the effect of various fiber types, fiber loading, and reinforcement conditions with different polymer matrices towards predicting the mechanical performance of such natural fiber composites. Cantilever beam and compression schemes were considered as two different mechanical loading conditions for structural applications of such composite materials. Finite element analysis was conducted to modeling the natural fiber composite materials. The interaction between the fibers and the matrices was considered as an interfacial friction force and was determined from experimental work by the pull out technique for each polymer and fiber type. Both polypropylene and polyethylene were considered as composite matrices. Olive and lemon leaf fibers were considered as reinforcements. Results have revealed that the deflection resistance of the natural fiber composites in cantilever beam was enhanced for several reinforcement conditions. The fiber reinforcement was capable of enhancing the mechanical performance of the polymers and was the best in case of 20 wt.% polypropylene/lemon composites due to better stress transfer within the composite. However, the 40 wt.% case was the worst in enhancing the mechanical performance in both cantilever beam and compression cases. The 30 wt.% of polyethylene/olive fiber was the best in reducing the deflection of the cantilever beam case. The prediction of mechanical performance of natural fiber composites via proper numerical analysis would enhance the process of selecting the appropriate polymer and fiber types. It can contribute finding the proper reinforcement conditions to enhance the mechanical performance of the natural fiber composites to expand their reliable implementations in more industrial applications.


2021 ◽  
Vol 879 ◽  
pp. 284-293
Author(s):  
Norliana Bakar ◽  
Siew Choo Chin

Fiber Reinforced Polymer (FRP) made from synthetic fiber had been widely used for strengthening of reinforced concrete (RC) structures in the past decades. Due to its high cost, detrimental to the environment and human health, natural fiber composites becoming the current alternatives towards a green and environmental friendly material. This paper presents an investigation on the mechanical properties of bamboo fiber reinforced composite (BFRC) with different types of resins. The BFRC specimens were prepared by hand lay-up method using epoxy and vinyl-ester resins. Bamboo fiber volume fractions, 30%, 35%, 40%, 45% and 50% was experimentally investigated by conducting tensile and flexural test, respectively. Results showed that the tensile and flexural strength of bamboo fiber reinforced epoxy composite (BFREC) was 63.2% greater than the bamboo fiber reinforced vinyl-ester composite (BFRVC). It was found that 45% of bamboo fiber volume fraction on BFREC exhibited the highest tensile strength compared to other BFRECs. Meanwhile, 40% bamboo fiber volume fraction of BFRVC showed the highest tensile strength between bamboo fiber volume fractions for BFRC using vinyl-ester resin. Studies showed that epoxy-based BFRC exhibited excellent results compared to the vinyl-ester-based composite. Further studies are required on using BFRC epoxy-based composite in various structural applications and strengthening purposes.


2014 ◽  
Vol 775-776 ◽  
pp. 308-313 ◽  
Author(s):  
Sergio Neves Monteiro ◽  
Frederico Muylaert Margem ◽  
Lucas Barboza de Souza Martins ◽  
Rômulo Leite Loiola ◽  
Michel Picanço Oliveira

Fibers of the giant bamboo (Dendrocalmus giganteus) are amongst the strongest lignocellulosic fibers. Although studies have been already performed, limited information exists on the mechanical properties of polymeric composites reinforced with continuous and aligned giant bamboo fibers. This work evaluates the tensile strength of this type of composite. Standard tensile specimens were fabricated with up to 30% of fibers aligned along the specimen length. The fibers were press-molded with a commercial polyester resin mixed with a hardener and cured for 24 hours at room temperature. The specimens were tensile tested in an Instron machine and the fracture surface analyzed by scanning electron microscopy. The tensile strength increased significantly with the amount of giant bamboo fiber reinforcing the composite. This performance can be associated with the difficult of rupture imposed by the fibers as well as with the type of cracks resulting from the bamboo fiber/polyester matrix interaction, which prevents rupture to occur.


Author(s):  
Р. Ш. Іскандаров ◽  
Н. В. Сова ◽  
Б. М. Савченко ◽  
І. І. П'ятничук ◽  
В. А. Татаренко

Study of the FFF additive manufacturing process of composite material based on L – polylactide (PLLA) with ultra-short carbon fibers. Tensile strength and elongation at break for all test specimens were determined according to ISO 527. Tensile modulus - ASTM D638-10, specimen density - PN-EN ISO 1183, microscopic examination - according to ASTM E2015 - 04 (2014). Charpy Shock Tests ISO 179 and ASTM D256. Bending test method ISO 178 and ASTM D 790. The rational modes of FFF additive manufacturing (AM) of carbon fiber composite based on PLLA was established. Properties of carbon fiber PLLA and unfilled PLLA was determinated for AM formed samples and injection molded samples. Carbon fiber composites have significantly higher flexural and tensile module us values compared to the original L-polylactide, which is due to the effect of polymer matrix reinforcement by the fibrous component. However, finished products obtained by AM PLLA carbon composite have a lower impact strength and tensile strength, which is likely to be due to the fact that the carbon fibers are short (50-60 mkm) and have a cavitations effect during injection molding and AM. Density of carbon fiber filled PLLLA was lower the theoretically calculated value for filament material as well for injection molded and AM formed samples. Density reduction probably the main cause of impact properties deterioration due to cavity forming around carbon fibers. Density and tensile properties of AM formed samples can be changed by AM slicing parameter – extrusion multiplier. Cavitation effect for carbon fiber composites observed for PLLA composite in form AM filament, injection molded parts and AM formed samples. Cavity forming was confirmed by optical microscopy and density measurement. Possible reason for cavity forming is orientation deformation of the fiber in polymer matrix during the formation of the filament. The effect of cavitation also persists in the AM of products from carbon composites due to the passage of the orientation at the exit of the printer nozzle.  The possibility of regulating the density and physical and mechanical properties of carbon composite products obtained by the additive manufacturing method has been established. Selection of rational values of the extrusion multiplier and the direction of the layers in the additive molding allows you to create products with the desired complex of properties.


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