scholarly journals Post-impact damage tolerance of natural fibre-reinforced sheet moulding compound

2020 ◽  
Vol 29 ◽  
pp. 2633366X2096793
Author(s):  
Harish K Patel ◽  
Ton Peijs

Natural fibre composites are of interest for a wide range of semi-structural applications in the building, construction and automotive sector. For a number of these applications, the evaluation of performance degradation after impact is of some relevance. The present work focused on the influence of fibre volume fraction and fibre surface treatment on the residual load-bearing capability of hemp fibre-reinforced sheet moulding compound (H-SMC) after non-penetrating impacts. Post-impact flexural strength and stiffness of H-SMC decreased linearly with increasing impact energy. At higher impact energy levels, the residual flexural strength of H-SMC improved with increasing fibre volume fraction. However, for the same amount of absorbed energy, the residual strength or damage tolerance capability of glass fibre-reinforced sheet moulding compound was about twice that of H-SMC. Composites based on surface treated hemp fibres showed a slight improvement in residual flexural strength, particularly for systems based on hemp fibres treated with a combined alkaline and silane surface treatment. Surface treated systems showed improved levels of adhesion and increased levels of energy absorption through potential mechanisms such as debonding, pull-out or fibre fibrillation.

2015 ◽  
Vol 773-774 ◽  
pp. 949-953 ◽  
Author(s):  
Izni Syahrizal Ibrahim ◽  
Wan Amizah Wan Jusoh ◽  
Abdul Rahman Mohd Sam ◽  
Nur Ain Mustapa ◽  
Sk Muiz Sk Abdul Razak

This paper discusses the experimental results on the mechanical properties of hybrid fibre reinforced composite concrete (HyFRCC) containing different proportions of steel fibre (SF) and polypropylene fibre (PPF). The mechanical properties include compressive strength, tensile strength, and flexural strength. SF is known to enhance the flexural and tensile strengths, and at the same time is able to resist the formation of macro cracking. Meanwhile, PPF contributes to the tensile strain capacity and compressive strength, and also delay the formation of micro cracks. Hooked-end deformed type SF fibre with 60 mm length and fibrillated virgin type PPF fibre with 19 mm length are used in this study. Meanwhile, the concrete strength is maintained for grade C30. The percentage proportion of SF-PPF fibres are varied in the range of 100-0%, 75-25%, 50-50%, 25-75% and 0-100% of which the total fibre volume fraction (Vf) is fixed at 0.5%. The experimental results reveal that the percentage proportion of SF-PPF fibres with 75-25% produced the maximum performance of flexural strength, tensile strength and flexural toughness. Meanwhile, the percentage proportion of SF-PPF fibres with 100-0% contributes to the improvement of the compressive strength compared to that of plain concrete.


2015 ◽  
Vol 659 ◽  
pp. 143-148 ◽  
Author(s):  
Rachamongkon Wongruk ◽  
Smith Songpiriyakij ◽  
Piti Sukontasukkul ◽  
Prinya Chindaprasirt

In this study, the mechanical properties of steel fibre reinforced geopolymer (SFRG) are investigated. The geopolymer is consisted of fly ash, silica fume and activator solution, sodium silicate and sodium hydroxide. Five mix proportions of fly ash and silica fume are varied to study the effect of fly ash/silica fume ratios (FA/SF). This experimental series focus mainly on flexural strength and flexural toughness performance of SFRG. Hooked-ends steel fibers are used at 0.5% and 1% by volume fractions. The experiment is carried out based on ASTM C1609 (beam specimens) for flexural performance. The results showed that fibre can significantly enhance the both flexural strength and toughness of geopolymer. The enhancement also increases with the increasing fibre volume fraction.


2014 ◽  
Vol 612 ◽  
pp. 131-137 ◽  
Author(s):  
Nadendla Srinivasababu ◽  
J. Suresh Kumar ◽  
K. Vijaya Kumar Reddy

In the present work a new natural fibre i.e. sacred grass botanically called Imperata Cylindrica is introduced and it belongs to vedic grass family. The fibre is extracted by splitting method and is reinforced into the polyester matrix by hand lay-up technique for the fabrication of tensile, flexural, impact, dielectric test specimens as per ASTM procedures. Highest values of tensile strength (50.96 MPa), modulus (990.86 MPa) are observed for sacred grass fibre reinforced polyester composites at maximum volume fraction of chemically treated fibre. At 14.75 %, 35.89 % sacred grass fibre volume fraction the composites exhibited flexural strength, modulus of 43.19 MPa, 4.81 GPa respectively. Impact strength of 92.53 kJ/m2 is obtained for the composites reinforced with 34.73 % volume fraction of sacred grass fibres. The dielectric strength of the composites varies from 10 to 6.66 kV/mm for composites reinforced with fibres from minimum (6.26 %) to maximum (32.25 %) fibre content.


2018 ◽  
Vol 5 (2) ◽  
pp. 304-309
Author(s):  
Hoo Tien Nicholas Kuan

Natural fibre reinforced polymer composite (NFRPC) has successfully replaced other synthetic fibre for applications in automobile, sport equipment, furniture, electrical appliances, etc. Artocarpus heterophyllus or jackfruit are mass produced in most South East Asia, but most of the parts other than the fruit would go to waste. In this study, Artocarpus heterophyllus fibre reinforced high density polyethylene (HDPE) composite was fabricated and tested for its mechanical properties, such as tensile and hardness properties. Artocarpus heterophyllus fibres were made into sheets using traditional paper making process, before being laminated with HDPE films using hot press method. Different volume fraction of fibre laminates were produced: 10%, 13%, 17% and 21%. The study shows that composite with 10%, 13% and 17% fibre volume fraction exhibits better tensile strength and hardness value than neat HDPE, while composites with 13%, 17% and 21% fibre volume fraction exhibit higher tensile modulus than neat HDPE. The optimum fibre content for the Artocarpus heterophyllus composite is 17%.


Currently, the attention on natural fibre reinforced concrete based materials could be seen increasingly rising around the world in the quest for economic and environmental importance in the construction sector and built environment. Hence this research will focus on inclusion of oil palm empty fruit bunch (EFB) fibre on drying shrinkage of lightweight foamed mortar (LFM). There were three densities of LFM was considered which were 800kg/m³, 1100kg/m³ and 1400kg/m³.The size for the empty fruit bunch (EFB) fibre was between 15-19mm with diverse volume fractions of 0.15%, 0.30%, 0.45% and 0.60% by LFM mix volume. The drying shrinkage test was performed according to American Standard ASTM C157. The test specimen dimension is a 75mm x 75mm x 275 mm prism shaped utilising a standard stainless mould which conforms to ASTM C490. The experimental results revealed that the inclusion of 0.3% EFB fibre in 800 kg/m3 density, 0.45% EFB fibre in 800 kg/m3 and 1400 kg/m3 densities possess the lowest percentage value of drying shrinkage at the final age of testing compared to control specimen and other EFB fibre volume fraction. In addition, EFB fibre exhibits a micrometer level diameter and hydrophilicity attributes which make it highly dispersible. It also has a capability to be distributed homogeneously along with the synchronicity of a great fibres quantity in unit volume of LFM.


Author(s):  
P Zhang ◽  
Q Li ◽  
Z Sun

The application of fly ash and silica fume in concrete composites by blending synchronously can improve the mechanical properties of concrete composites. However, the concrete composite becomes much brittle with the usage of fly ash and silica fume. Polypropylene fibre is often used to improve the ductility of concrete composites. This article discusses the effect of polypropylene fibre on the flexural properties of concrete composites containing fly ash and silica fume. Results reveal that the addition of polypropylene fibre can increase the flexural strength and decrease the flexural modulus of elasticity of the concrete composite containing fly ash and silica fume evidently. Furthermore, it is indicated that an increase in the fibre volume fraction leads to an increase in the flexural strength and a decrease in the flexural modulus of elasticity when the fibre volume fraction is not beyond 0.12 per cent. Polypropylene fibre seems to play an important role to improve the ductility of concrete composites containing fly ash and silica fume.


2019 ◽  
Vol 8 (3) ◽  
pp. 7187-7193

Natural fibres such as kenaf, jute, bamboo, flax and wood have been the subject of intensive researches in the area of fibre reinforced composite due to their environmental advantages of being renewable, biodegradable and sustainable. Bamboo fibre can be a good choice of natural fibre reinforcement for structural applications due to its excellent strength to weight ratio that is comparable to that of mild steel. In this study, mechanical properties of both continuous and short bamboo fibre reinforced composites are predicted using micromechanical approaches. The finite element method was used where three-dimensional micromechanical representative volume element with square and hexagonal packing geometry was implemented. The results were then compared with the findings from analytical approach that includes the rule of mixture and the Halpin-Tsai model. It was found that for all properties, the FEM and analytical methods give comparable trends of property on volume fraction plots. Furthermore, the longitudinal modulus given by all models are in excellent agreement as it increases linearly with the increase in bamboo fibre volume fraction.


2020 ◽  
Vol 53 (2) ◽  
pp. 57
Author(s):  
Dyah Anindya Widyasrini ◽  
Siti Sunarintyas

Background: Composite resins are widely used in dentistry to restore dental caries. Recently, short fibre-reinforced composite (FRC) resins have been widely used for high-stress areas, especially in posterior teeth. Bombyx mori silk fibre is under research to reinforce dental composite resin as it has good mechanical properties. Purpose: This study aims to obtain the effects of alkalisation and silk fibre volume fraction on the flexural strength of FRC. Methods: Bombyx mori silk fibres were obtained from Perhutani, Pati, Indonesia. Samples were divided into two alkalisation groups (4% and 8%). Alkalisation of the silk fibres was conducted through the scouring process in NaOH, hydrolysis (30% H2SO4) and drying. Silk fibres were then reinforced in a resin matrix. The samples were subdivided based on the fibre volume fraction reinforcements, which were 0%, 5%, 10% and 15%. Each group of samples consisted of three specimens (n = 3). Flexural strength was measured using a universal testing machine. Data were analysed by two-way ANOVA (p < 0.05) and post-hoc least significant difference test (p < 0.05). Results: The results showed the flexural strength (MPa) means of the 4% alkalisation group were 169.31 ± 54.28 (0%), 76.08 ± 43.69 (5%), 107.86 ± 40.61 (10%) and 101.99 ± 10.61 (15%). The flexural strength (MPa) means of the 8% alkalisation group were 169.31 ± 54.28 (0%), 82.62 ± 22.41 (5%), 111.07 ± 32.89 (10%) and 153.23 ± 23.80 (15%). Statistical analysis by ANOVA indicated that the fibre volume fraction affected the flexural strength of composite resins. Conclusion: It can be concluded that the volume fraction of silk fibre increases the flexural strength of composite resins, although the strength is not as high as a composite resin without fibres. However, the alkalisation percentage did not affect the flexural strength of composite resins, and there was no interaction between alkalisation percentage and fibre volume fraction with the flexural strength of composite resins.


2021 ◽  
pp. 096739112110239
Author(s):  
Sheedev Antony ◽  
Abel Cherouat ◽  
Guillaume Montay

Nowadays natural fibre composites have gained great significance as reinforcements in polymer matrix composites. Composite material based on a polymer matrix reinforced with natural fibres is extensively used in industry due to their biodegradability, recyclability, low density and high specific properties. A study has been carried out here to investigate the fibre volume fraction effect of hemp fibre woven fabrics/PolyPropylene (PP) composite laminates on the tensile properties and impact hammer impact test. Initially, composite sheets were fabricated by the thermal-compression process with desired number of fabric layers to obtain composite laminates with different fibre volume fraction. Uniaxial, shear and biaxial tensile tests were performed and mechanical properties were calculated. Impact hammer test was also carried out to estimate the frequency and damping parameters of stratified composite plates. Scanning Electron Microscope (SEM) analysis was performed to observe the matrix and fibre constituent defects. Hemp fabrics/PP composite laminates exhibits viscoelastic behaviour and as the fibre volume fraction increases, the viscoelastic behaviour decreases to elastic behaviour. Due to this, the tensile strength increases as the fibre content increases. On the other hand, the natural frequency increases and damping ratio decrease as the fibre volume fraction increases.


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