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Different Techniques for Designing and Fabrication of Advanced Composite Materials
Published in Subhash Singh, Dinesh Kumar, Fabrication and Machining of Advanced Materials and Composites, 2023
Subhash Singh, Rama Kanti, Vikas Kumar
The spray lay-up technique is similar to that of the hand lay-up process except that a hand gun is utilized in this process to spray a combination of the resin and chopped Fibre, as shown in Fig. 3.1b. An inexpensive mold is employed for fabricating large products. The resin-Fibre mixture is sprayed into the mold and allowed to completely cure at ambient temperature, following which the final composite is obtained. Prior to curing, the resin-Fibre mixture is rolled using the rollers to get rid of the voids as well as bubbles [9]. Rollers and brushes are employed to clean the wet Fibre as well as the air. The mechanical characteristics of the final composite are influenced by the orientations as well as the constraints of the Fibres.
Composite Processing
Published in Zainul Huda, Manufacturing, 2018
In the hand lay-up process, layers of composite fiber are built up in a sequenced lay-up using a matrix of resin and hardener to form a laminate stack. The laminate stack is then “cured.” The simplest curing method involves allowing cure to occur at room temperature. However, heat and/or pressure may be applied to accelerate curing.
Sugar Palm Fiber–Reinforced Polymer Hybrid Composites: An Overview
Published in S.M. Sapuan, J. Sahari, M.R. Ishak, M.L. Sanyang, Sugar Palm Biofibers, Biopolymers, and Biocomposites, 2018
I. Mukhtar, Z. Leman, M. R. Ishak, E. S. Zainudin
In similar research by Sapuan et al. (2013), a glass fiber and SPF-reinforced unsaturated polyester was investigated to determine the tensile, flexural, and impact properties at different glass:SPF ratios. The composite was fabricated using a hand lay-up process and compression molding. The glass fiber was in a strand mat form, and the SPF was randomly arranged to form a mat after being cut into strands approximately 50 mm long. The mechanical properties of the non-hybrid and the hybrid composites are shown in Table 8.3. The hybrid composite with a glass/SPF weight ratio of 4:4 had mechanical properties high than other ratios and the non-hybrid composites. Generally, the results obtained by Sapuan et al. (2013) are much higher, with tensile strength, tensile modulus, and impact strength values of 61.69 MPa, 8.12 GPa, and 4.90 kJ/m2, respectively, compared with 30.5 MPa, 1.8 GPa, and 2.5 kJ/m2, respectively, as obtained by Misri et al. (2010). This wide variation could be due to the percentage of the glass fiber used in the hybrid composite because the type of fibers and the manufacturing process were the same in these two studies. All the studies highlighted showed that the non-hybrid SPF composites had lower mechanical properties compared with the hybrid composites. Specifically, the tensile strength and impact strength increased significantly.
Durability prediction analysis on mechanical properties of GFRP upon immersion in water at ambient temperature
Published in Cogent Engineering, 2021
Suhas Kowshik, Gowrishankar M C, Manjunath Shettar, Ritesh Bhat, Gurumurthy B M
In the present work, investigations are carried out to learn the effect of water immersion at ambient temperature on the tensile and flexural strengths of glass fiber-polyester composites. Composites are fabricated by hand lay-up process with varying weight percentages of glass fiber, i.e., 30, 40, and 50 wt.%. Composite specimens are immersed in water at ambient temperature. Tensile and flexural tests are carried out for unaged and aged specimens. SEM images are carefully inspected to learn about the effect of water immersion on the composites. The following conclusions are made on the basis of the study carried out: The composite’s tensile and flexural strengths are 145 MPa and 302 MPa at 30 wt.% of glass fiber, respectively, whereas tensile and flexural strengths are increased to 158 and 333 MPa 40 wt.% of glass fiber and 170 MPa and 353 at 50 wt.% of glass fiber, respectivelyWater-immersed samples show decreased tensile and flexural strengths for all three glass fiber weight percentages. Tensile strength of composite specimens immersed for 180 days reduced by 15–25%, and flexural strength reduced by 9–16%.The retention rate of tensile and flexural strengths is higher at 50 wt.% glass fiber, i.e., 86 and 92%, respectively, compared to 30 and 40 wt.% of glass fiber.SEM images of the fractured surface revealed the reasons for the failure of the specimens under tensile load viz., fiber pull-out, matrix fracture, fiber-matrix de-bonding, and fiber breakage.The error percentages between experimental and predicted values are very minimal (i.e., less than 1%) for the duration of immersion up to 60 days.
An application of Taguchi method for fabrication factors optimisation of banyan aerial root fibre reinforced polymer composite
Published in Australian Journal of Mechanical Engineering, 2023
Milon Selvam Dennison, Rajasekaran R
Matrix materials are used to support and protect the fibres (Yin et al. 2017). They also provide a means of distributing load among the fibres and transmitting load between the fibres. The curing of resin is a very important process during the development of composites and can be done with catalysts and accelerators. The determination of an appropriate medium and the measure of the medium to be utilised in any application relies on the resin, the temperature at which the resin is to be treated, the necessary working or pot-life and the hour of gelation. There is no such medium accessible which can meet all the prerequisites. Accordingly, a mix of medium and quickening agents must be utilised to get the best outcomes. Methyl Ethyl Ketone Peroxide is utilised as the medium. The temperature at which the resin is to be relieved and the pace of restoring is constrained by the medium. A medium can go about as an initiator for the polymerisation procedure. Curing time can be constrained by the differing catalyst. It doesn’t prompt a full fix of the surrounding temperature without anyone else. In any case, by including an accelerator the catalyst will cause gelation and will prompt a fix inside a brief timeframe relying upon the nearness of the constituent utilised in the gum. Cobalt naphthenate is utilised as an accelerator to fix the resin without applying any heat to it. Cobalt naphthenate is accessible as an answer containing 6% of cobalt metal. It helps in initiating the gelation of the pitch and proliferation of complete fix at room temperature related to peroxide. In this study, banyan aerial roots are used as reinforcement, were collected from the southeastern part of India and treated with NaOH solution. Besides, NaOH to natural fibres alters the ionisation of the hydroxyl group to the alkoxide (Del Rey et al. 2017). Various sizes of banyan aerial root fibres with NaOH treated and untreated conditions were considered for the preparation of polymer matrix composites. The extracted fibre from the source of the banyan aerial root is shown in Figure 2. A mould made up of sheet strips of 2 mm thickness, two such strips placed together to obtain the required thickness and of the mould dimension is (200 mm x 200 mm x 3 mm) is prepared. Processing of the composite materials is done in this mould by hand layup process. Later specimens are cut from the prepared composite laminates according to the ASTM Standards. The mixing of the epoxy resin (Araldite LY 556) and anhydride hardener (HY 917) is made at a ratio of 10:1. This solution is used to mix polymer mat matrix and banyan aerial root natural fibres at a ratio of 30% natural fibre and 70% polymer. The composition of the fabrication is presented in Table 3.