Showing papers by "Faizal Mustapha published in 2020"
TL;DR: In this paper, the authors reviewed the healing agent carrier preparation for vascular self-healing systems and compared the vascular healing system with intrinsic selfhealing, showing that in most cases, preparation of healing agents is challenging greater than understanding the healing mechanism.
Abstract: Self-healing polymer materials have the functional characteristics of curing when a crack penetrates the material. Damage response, healing ability and healing performance are the most important healing characteristics of a self-healing material. Self-healing in a material system is employed through different methodologies, such as capsulation, vascular filling and intrinsic healing systems. The most challenging factor in fabrication of self-healing material is the ‘carrier filling’ in both the vascular and capsule type healing methods. The self-healing is either autonomic or external, depending on the actuation of the healing. This paper reviews the healing agent carrier preparation for vascular self-healing systems and compares the vascular healing system with intrinsic self-healing. The review revealed that, in most cases, preparation of healing agents is challenging greater than understanding the healing mechanism. The behaviour of self-healing material under fatigue, impact, and ballistic characterisation is also reviewed towards suggesting the self healing materials for aerospace applications.
38 citations
TL;DR: The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future.
Abstract: This study aims to explore the mechanical properties of hybrid glass fiber (GF)/sisal fiber (SF)/chitosan (CTS) composite material for orthopedic long bone plate applications The GF/SF/CTS hybrid composite possesses a unique sandwich structure and comprises GF/CTS/epoxy as the external layers and SF/CTS/epoxy as the inner layers The composite plate resembles the human bone structure (spongy internal cancellous matrix and rigid external cortical) The mechanical properties of the prepared hybrid sandwich composites samples were evaluated using tensile, flexural, micro hardness, and compression tests The scanning electron microscopic (SEM) images were studied to analyze the failure mechanism of these composite samples Besides, contact angle (CA) and water absorption tests were conducted using the sessile drop method to examine the wettability properties of the SF/CTS/epoxy and GF/SF/CTS/epoxy composites Additionally, the porosity of the GF/SF/CTS composite scaffold samples were determined by using the ethanol infiltration method The mechanical test results show that the GF/SF/CTS hybrid composites exhibit the bending strength of 343 MPa, ultimate tensile strength of 146 MPa, and compressive strength of 380 MPa with higher Young’s modulus in the bending tests (2156 GPa) compared to the tensile (6646 MPa) and compressive modulus (2046 MPa) Wettability study results reveal that the GF/SF/CTS composite scaffolds were hydrophobic (CA = 9241° ± 171°) with less water absorption of 3436% compared to the SF/CTS composites (6953%) The SF/CTS composites show a hydrophilic character (CA = 5428° ± 306°) The experimental tests prove that the GF/SF/CTS hybrid composite can be used for orthopedic bone fracture plate applications in future
26 citations
TL;DR: In this paper, a secondary study was carried out to explore the effect of compression factor during fabrication on the mechanical properties of the composites, and the results showed that, compression factor had a direct relation with increasing compression factor up to a certain value beyond which a drop in properties was seen.
Abstract: 3-D E-glass fabric reinforced epoxy composites at 6mm thickness were fabricated for various orientations of the binder yarn viz. 0◦, 30◦, 45◦, 60◦ and 90◦ respectively. Tensile, flexural, interlaminar shear stress tests were conducted to ascertain the influence of binder yarn
orientation on the mechanical properties of the composites. The composites with 0◦ binder yarn orientation showed the best strength followed by 90◦ whilst the others showed highly depleted traits in comparison. Shear stress induced at the interface of each lamina was seen as the major reason for drop in the strength. A secondary study was carried out to explore the effect of compression factor during fabrication on the mechanical properties of the composites. Laminates with varying thickness namely, 4mm, 5mm and 7mm but, with
same number of plies of 3D E-glass fabric at 0◦ orientation were fabricated. The test results
were compared with the results of 6mm composites from the primary study. The results showed that, compression factor affected the mechanical properties of the composites and had a direct relation with increasing compression factor up to a certain value beyond which
a drop in properties was seen. Composites pressed to a thickness of 5mm showed the best properties. Drop in properties was attributed to close packing of reinforcement and crushing of fibres leading to inefficient stress transfer. Scanning electron microscopy was employed to understand the modes of failure. The major failure modes observed were delamination,
matrix cracking and debonding. Based on the results obtained, these composites can be seen as a material system for applications like ballistic armours, structural renovations and automobile components
16 citations
TL;DR: The microstructure analysis revealed that coating with high adhesion strength had good interfacial bonding with the substrate, and had good wetting ability in which the coating penetrated the valleys of the profiles, thus wetting the entire substrate surface.
Abstract: As a result of their significant importance and applications in vast areas, including oil and gas, building construction, offshore structures, ships, and bridges, coating materials are regularly exposed to harsh environments which leads to coating delamination. Therefore, optimum interfacial bonding between coating and substrate, and the reason behind excellent adhesion strength is of utmost importance. However, the majority of studies on polymer coatings have used a one-factor-at-a-time (OFAT) approach. The main objective of this study was to implement statistical analysis in optimizing the factors to provide the optimum adhesion strength and to study the microstructure of a rice husk ash (RHA)-based geopolymer composite coating (GCC). Response surface methodology was used to design experiments and perform analyses. RHA/alkali activated (AA) ratio and curing temperature were chosen as factors. Adhesion tests were carried out using an Elcometer and a scanning electron microscope was used to observe the microstructure. Results showed that an optimum adhesion strength of 4.7 MPa could be achieved with the combination of RHA/AA ratio of 0.25 and curing temperature at 75 °C. The microstructure analysis revealed that coating with high adhesion strength had good interfacial bonding with the substrate. This coating had good wetting ability in which the coating penetrated the valleys of the profiles, thus wetting the entire substrate surface. A large portion of dense gel matrix also contributed to the high adhesion strength. Conversely, a large quantity of unreacted or partially reacted particles may result in low adhesion strength.
10 citations
14 Sep 2020
TL;DR: In this article, the authors investigated the contribution of multivariate processing parameters such as bagging techniques, curing profiles, and laminate structures on laminates' shape conformation, and provided guidelines to reduce thickness variations and spring effect in laminated composites with complex shapes.
Abstract: Complex composite structures manufactured using a low-pressure vacuum bag-only (VBO) method are more susceptible to defects than flat laminates because of the presence of complex compaction conditions at corners. This study investigates the contribution of multivariate processing parameters such as bagging techniques, curing profiles, and laminate structures on laminates’ shape conformation. Nine sets of laminates were produced with a concave corner and another nine sets with a convex corner, both with a 45° inclined structure. Three-way analysis of variance (ANOVA) was performed to quantify thickness variation and spring effect of laminated composites. The analysis for concave and convex corners showed that the bagging techniques is the main factor in controlling the laminate thickness for complex shape applications. The modified (single) vacuum-bag-only (MSVB) technique appeared to be superior when compared to other bagging techniques, exhibiting the least coefficients of variation of 0.015 and 0.016 in composites with concave and convex corners, respectively. Curing profiles and their interaction with bagging techniques showed no statistical significance in the contribution toward laminate thickness variation. The spring effect of laminated composites was investigated by calculating the coefficient of determination (R2) relative to that of the mold. The specimens exhibited a good agreement with R2 values ranging from 0.9824 to 0.9946, with no major data offset. This study provides guidelines to reduce thickness variations and spring effect in laminated composites with complex shapes by the optimum selection of processing parameters for prepreg processing.
10 citations
TL;DR: In this article, a three-point bending test and scanning electron microscope were used to investigate the flexural properties and microstructure of the geopolymer composite coating (GCC), respectively.
Abstract: If the coating is sufficiently flexible, no tears, cracks, or debond will occur. Although geopolymers have a great potential as a coating material, research on the flexural properties is very limited. In this study, a three-point bending test and scanning electron microscope were used to investigate the flexural properties and microstructure of the geopolymer composite coating (GCC), respectively. Response Surface Methodology (RSM) consists of a combination of mathematical and statistical techniques, which is useful in modelling, analyzing, and optimizing responses that are influenced by several factors. It was used in determining the relationship between each factor and determining the best composition for the composite coating. Several factors were considered including ratio of activated alkaline (AA) solution (V1), RHA/AA ratio (V2), and curing temperature (V3). Results showed that the RHA/AA ratio mostly influenced the response, followed by curing temperature while the ratio of AA was not significant. Lower V2 and V3 values provided the highest flexural strength and modulus. The optimum composition which provided the best coating of flexural properties were V1 = 3.5, V2 = 0.39, and V3 = 45.7 °C. Microscopic images showed that coating with high flexural properties (ductile coating) exhibited minor and rough cracks as compared to that of coating with low flexural properties (brittle coating) which displayed a crack with a clean linear cut. Brittle coating was highly agglomerated and has a significant negative effect on the flexural properties. By developing the optimum composition, the GCC may potentially be a good alternative as a building construction coating material.
10 citations
10 Jul 2020
TL;DR: A review of the literature reveals that considerable progress has been made in the improvement of the properties of the weld joint by the application of several weld treatment processes, with little attempt to establish a relationship between the microstructure and properties as discussed by the authors.
Abstract: For the past three centuries, there has been a very high demand for stainless steel for different applications, due to its corrosion resistance coupled with the good strength and low cost of the metal. Several welding techniques have been adopted in the fabrication of stainless steel, with the choice of welding technique hinged on the desired requirements. Advancement has been made in its dissimilar welding with other metals like aluminum, copper and titanium. While similar welding of stainless steel faces the challenge of weld metal property deterioration, dissimilar welding poses more serious challenges due to the differential in chemical composition and the thermophysical properties of the base metals. A review of the literature reveals that considerable progress has been made in the improvement of the properties of the weld joint by the application of several weld treatment processes. It was discovered that most of the researchers focused on the effect of these weld treatment processes on the properties of the weld joints, with little attempt to establish a relationship between the microstructure and properties. This review paper critically analyzed the effect of weld treatment processes on the properties of stainless steel in light of microstructure-property correlation.
8 citations
TL;DR: In this article, a 2-level fractional factorial design (2-FrFD) was used to screen and identify important factors affecting the behavior of geopolymer binder.
Abstract: Despite numerous studies on the factors which influenced the properties of the geopolymer binder have been conducted, the effect of different factors on the properties of geopolymer binder was not well determined. In this research, geopolymer materials were analyzed and profiled using a statistical approach called 2-level fractional factorial design (2-FrFD). The objective is to screen and identify important factors affecting the behaviour of geopolymer binder. MINITAB, a statistical software, was used to design the experiment, analyze data obtained and present the significance value of the factors via chart and plots. The result showed that the curing temperature (V3) did not have a significant effect on the fire resistant properties of the geopolymer binder with the p-value of 0.526. Other factors and interaction were significant with RHA/AA ratio (V2) was the most significant factor with the coefficient value of 135. For the compression strength properties, all factor and interactions were significant (p-value between 0.000 and 0.009) with the RHA/AA ratio (V2) recorded the highly significant factor with the coefficient value of 8.838. For adhesion strength properties, NaOH concentration (V4) and curing time (V5) were found to be insignificant with the p-value of 0.223 and 0.133, respectively. Other factors and interaction were significant curing temperature (V3) was the most significant factor with the coefficient value of 0.287. This result may hugely benefit future researchers, towards producing halal and sustainable polymer, in determining the suitable factors which have a significant effect of the properties (outcome) of the geopolymer binder.
2 citations
TL;DR: The True Hybrid Wind-Solar (THWS) generator as discussed by the authors allows for the solar panels to rotate along with a VAWT wind turbine that is attached through a specially designed electromechanical coupling mechanism.
Abstract: Contemporary hybrid solar-wind farms are commonly implemented using separate solar photovoltaic (PV) cell arrays and wind turbines, where the electricity currents generated from both devices are combined. However, this solution requires a large amount of space to cater for the PV arrays and wind turbines of the system. This paper proposes a new type of renewable energy electric generator with a small power production footprint (PPF) that allows reduction of land usage. The True Hybrid Wind-Solar (THWS) generator allows for the solar panels to rotate along with a VAWT wind turbine that is attached through a specially designed electromechanical coupling mechanism. The working principle behind the connections is described in this paper. The design of a hybrid circuit module that serves to combine the currents generated via the solar cells and the wind generator and also to automatically disconnect inactive wind or solar generators is described. The latter is important in order to eliminate unwanted load generated from the inactive generators within the THWS itself.
TL;DR: Incremental sheet forming (ISF) is a promising sheet forming process and becomes a worthy alternative to the traditional sheet forming processes as discussed by the authors, which is used in manufacturing small batch or custom...
Abstract: Incremental sheet forming (ISF) is a promising sheet forming process and becomes a worthy alternative to the traditional sheet forming processes. ISF has used in manufacturing small batch or custom...