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Natural Fiber Composites Manufacturing Techniques
Published in Magdi El Messiry, Natural Fiber Textile Composite Engineering, 2017
This is the simplest and widely used for many years way for the composite formation, especially for large size composites, such as in the boat manufacturing. The reinforcement in this case will be in the form of mat of woven, knitted, or nonwoven. The short fibers or yarns require efforts to get uniform thickness of the formed preform. The thermosetting resin is used and the impregnation of the reinforcement is carried out manually using roller brush to distribute the resin on the surface of the reinforcement and apply enough pressure to allow the resin to penetrate through the reinforcement without voids, Figure 6.2. The preform may consist of several laminates, so the process will be repeated layer by layer. Resin used may be epoxy, polyester, vinyl ester, and phenolic. However, the quality of the preform depends on the skills of the labor. Due to the high fiber volume ratio, the probability of void formation increases. In order to reduce these risks, a vacuum bag is used to suck the air from the unreachable spaces, helping the resin to reach them. Hand lay or open mold technique is also connected with feeding of the fibers which are cut into small length, may reach micro size, mixed with the polymer and sprayed in the open mold.
Fiber–Matrix Interphase Effects on Damage Progression in Composite Structures
Published in Frank Abdi, Mohit Garg, Characterization of Nanocomposites, 2017
Levon Minnetyan, Xiaofeng Su, Frank Abdi
Assume a square-packed array of fibers in a unidirectional lamina. Each fiber will have a square region of matrix with side a surrounding it, as shown in Fig. 3.1. Considering a unit depth into the figure, the fiber volume ratio is written as () kf=πd24a2orda=2kfπ
Introduction
Published in P. K. Mallick, Processing of Polymer Matrix Composites, 2017
Assume that the unidirectional fibers in a PMC are arranged in a square array as shown in the following figure. Fiber cross-sections are shown at each corner of the array. If the fiber volume fraction is 60% and the fiber diameter is 7 μm, what is the distance between each fiber? What is the fiber surface area-to-fiber volume ratio in the composite?
Experimental and numerical analysis of different natural fiber polymer composite
Published in Materials and Manufacturing Processes, 2023
Savendra Pratap Singh, Akriti Dutt, Chetan Kumar Hirwani
The tensile test results was obtained by testing the composite specimens using universal testing machine supplied by Aimil Limited, Bangalore, India. The specimens were prepared in dog bone shape as per ASTM D638 standard. The obtained results are shown in Table 3. From Table 3 results, it can be concluded that with addition of natural fiber in composite tensile strength, load bearing capacity of composite enhances. The lowest value of ultimate tensile strength found with 10% coir fiber that is 19.07% lesser than the obtained ultimate tensile strength of 10% bamboo fiber and 28.05% lesser than the obtained ultimate tensile strength of 10% hemp fiber. The load bearing capacity associated with 10% hemp fiber is 19.07% and 38.61% more than the load bearing capacity of 10% bamboo and 10% hemp, respectively. The highest extension 6.9 mm is found in 15% bamboo fiber and lowest in 10% coir. Chemical analysis of hemp fiber shows an average 70–90% part of hemp fiber made up of cellulose and weak lignin was found to be around 3–5%. Due to the presence of highest cellulose percentage, hemp fiber composite shows better mechanical properties amongst coir, bamboo and hemp fiber composite. The stress-strain diagram of all samples is shown in Figure 3. In case of bamboo fiber with epoxy matrix, the adhesion between fiber and matrix is better than the adhesion between coir fiber with epoxy matrix. This may be one reason that mechanical properties associated with bamboo fiber composite was found better than the coir fiber composite and similar may be for hemp fiber. The highest ultimate strength 180.546 MPa was found for 20% hemp fiber. With increase in fiber volume ratio, that is, fiber percentage in composite, the tensile properties of composite enhance up to a limit. The stress-strain diagram of all test composite is shown in Figure. 3.
The review about the numerical modelling and analysis of 3D woven fabrics
Published in The Journal of The Textile Institute, 2022
The permeability properties of 3D woven fabrics become crucial in composite production. The amount and distribution of resin on the fabric directly affect the fiber volume ratio of material. The fibre volume ratio is main parameter to impress the mechanical properties of composites. It is significant in the composite production that every section of fabric should be completely treated with the resin. Otherwise, dry parts make the properties worse and cause the serious defects on the material.