A Data-driven Framework Combining Ahp-topsis and Rsm-based Desirability for Optimal Hybrid Composite Laminate Selection

Ferrite and nano‐barium titanate reinforced poly(ether ether ketone) (PEEK) composites were made by compression moulding technology. The effects of reinforcement of the ferrite and nano‐barium titanate on the PEEK matrix were studied with the aim assessing its potential as a radar‐absorbing structural material (RASM). With an increase in the percentage filling of ferrite in the PEEK matrix, the specific gravity, hardness, tensile and flexural moduli, brittleness, dielectric constant, loss tangent and reflection losses were increased, while the tensile and flexural strengths, and elongation at break, were decreased. With increasing nano‐barium titanate reinforcement in the ferrite‐filled PEEK composites, the specific gravity, hardness, tensile and flexural strengths, tensile modulus and dielectric constant were comparatively increased, while the elongation at break, flexural modulus and loss tangent (marginally) were decreased. Reinforcement of the nano‐barium titanate caused a comparatively marginal reduction in the loss tangent, although no effect on reflection losses was observed. The solubility resistance of the ferrite‐filled PEEK composites was improved with reinforcement by the nano‐barium titanate. Copyright © 2004 Society of Chemical Industry

This research examines the mechanical properties of composites made from flax fiber and polyester resin. Hybrid composites were produced by integrating flax fiber, known for its exceptional tensile and flexural strengths, with graphene oxide nanoparticles (nGO) and polyester resin. The flexural and ultimate tensile strengths of the composites were predicted using a multilayer perceptron (MLP) regression model, a type of artificial neural network (ANN). The composite material FGO-1, comprising 40 wt.% flax fiber, 1 wt.% graphene oxide nanoparticles, and 59 wt.% polyester resin, exhibited outstanding mechanical properties. The FGO-1 sample showed improvements in flexural modulus (46.80%), flexural strength (50.80%), tensile modulus (32%), and tensile strength (37.83%). The energy absorption rate was 32.69%, and its impact resistance exceeded that of the other composite formulations by 8.75%. The ANN model successfully predicted these strengths, achieving R2 values of 0.89 and 0.98 for flexural and tensile strengths, respectively. Microstructural analysis using a scanning electron microscope (SEM) was conducted alongside tensile, flexural, impact, and interlaminar shear strength tests to evaluate the composite’s performance.

The mechanical and morphological characteristics of PA6/ABS (60/40)-based hybrid composite containing HNO3-treated short carbon fibers (HSCF) and CaCO3 nanoparticles have been experimentally studied. A counter-rotating twin-screw extruder and an injection molding machine were employed to produce different samples containing 10 wt % of HSCF and 0, 2, 5 and 8 wt % of CaCO3 nanoparticles. The SEM observations indicated high-quality adhesion between HNO3-surface treated carbon fibers and PA6/ABS polymer matrix. In addition, the morphological studies showed that the inclusion of CaCO3 nanoparticles caused a significant effect on the ABS particle dispersion in PA6/ABS matrix. The mechanical properties assessments revealed that the incorporation of 10 wt % HSCF into the PA6/ABS can significantly improve tensile strength (82%), tensile modulus (107%), flexural strength (98%), flexural modulus (104%) and impact resistance (24%). The inclusion of CaCO3 nanoparticles, in the presence of 10 wt % HSCF, led to the noticeable improvements of tensile strength (128% for 2 wt % CaCO3), tensile modulus (199% for 5 wt % CaCO3), flexural strength (146% for 5 wt % CaCO3), flexural modulus (204% for 5 wt % CaCO3) and impact resistance (46% for 2 wt % CaCO3). The surface treatment of carbon fibers, dispersion conditions of nanoparticles and ABS phase in polymeric matrix were found to be the major important factors affecting the mechanical properties.

Sensitivity analysis of abrasive air-jet machining parameters on machinability of carbon and glass fiber reinforced hybrid composites

Flax fibre composite is a bio-material that can meet the requirements in many engineering applications. It has been used especially in applications for the automotive industry due to the several excellent specific properties which are similar to composites manufactured with glass fibres. However, due to the hydrophilic nature of flax fibre, this material is prone to absorb water and moisture from the environment, and therefore, they are not reliable for outdoor applications. The growing demand for flax composites in the field of bio-material research enforces the researchers to have in-depth knowledge in their processing into a useful final product. However, the correlation between the environmental effects and the performance of the flax fibre bio-composites is not well established. The main focus of this study is to address the specific environmental issues and their effects on flax fibre composites manufactured by the vacuum infusion method. First of all, the effect of the moisture content in the fibres on the mechanical performance and overall quality of the manufactured composites is studied. Flax composites are manufactured with fibres having different moisture content and they are compared to composites manufactured with dry fibres. This work begins with measuring moisture absorption kinetics of the flax fibres. Flax fibres absorb moisture almost linearly from 0% to 70% RH (relative humidity) environments, however, this absorption almost double from 70% to 95% RH. The tensile strength of the flax fibre reinforced composites increases until a certain RH value (50% RH) and then it decreases as the RH of the environment is raised up to the maximum value (95% RH). However, the tensile modulus, flexural strength and modulus of the composite samples continuously decrease with the increasing RH values. The microstructural tests of the composites confirmed the presence of micro-cracks and pores and debonding in the fibre-matrix interface. In addition, a study about the dynamic response of the flax composites manufactured with fibres stored at different RH levels ensures that dry composites have better vibration and damping properties. The damping ratios of the flax composites manufactured with fibres with different RH values are slightly increased with the increasing rates of moisture absorption although this change is not notable. Moreover, the mechanical properties of the flax composites manufactured with fibres at different RH environments are predicted by analytical models. The geometric and displacement potential function approaches are proposed to estimate the tensile properties of the flax composites. The proposed models demonstrate greater accuracy when validated with experimental observations. Secondly, the consequence of different environmental conditions on the performance and durability of flax composites is analysed. Composites made by vacuum infusion using dry fibres are immersed in water, exposed to warm humid environments and subjected to freeze-thaw (F/T) cycles. During exposure to different environments, the mechanical performance (tensile and flexural properties), moisture content and physical changes (dimensional stability) of the composites are analysed. The water absorption trend is partially Fickian for the samples immersed in water at room temperature and these samples are greatly affected and degraded. Furthermore, the mechanical properties of the water saturated (WS) samples are clearly degraded in contrast to the as manufactured (AM) samples. Compared to AM samples, the tensile strength and modulus are decreased approximately by 9% and 57%, respectively for WS samples and their flexural strength and modulus is decreased by 64% and 70%, respectively. However, some of these properties could be recovered, to some extent, by drying the WS samples. On the other hand, the reduction of tensile strength and modulus for the humidity saturated (HS) samples is only 0.8% and 3%, respectively, when compared to the AM composite samples. It was found that freezing-thawing cycles have almost no effects on the flax bio-composites.

Influence of polymerization mode on flexural properties of esthetic resin luting agents

Nanoclay weight percent, glass fiber volume percent and angle of orientation of fibers were selected as parameters to study their effect on tensile and flexural characteristics of epoxy-glass-clay nanocomposites (EGCNs). Response surface method (RSM) was utilized to analyze and fit a regression model for the tensile and flexural strength. The optimum values of ultimate tensile strength (UTS) and flexural strength (σf) were 273.47 and 210.14 MPa, respectively, which were predicted using regression models at 2.5% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. The predicted results were confirmed by performing experiments at the optimum conditions which were obtained as 262.37 and 214.76 MPa. The optimized result showed that UTS and σf were improved up to 30.8% and 36.3% compared to the composite containing 0% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. The optimum values of tensile and flexural modulus were obtained as 25.99 and 11.81 GPa, respectively, which were 12.2% and 10.7% higher compared to those values of EGCN containing 0% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. XRD test conducted to check the intercalation/exfoliation of the clay in the composite. The fracture surfaces of the EGCNs investigated by scanning electron microscopy (SEM) revealed that the failure occurred by crack propagation in the matrix followed by fiber breakage with little fiber-matrix debonding, whereas in case of EGCN with 0% (by wt) C15A fiber-matrix debonding followed by fiber breakage was observed.

In this research, investigate the effect of weight fraction (1%, 2%, 3%, 4%) industrial waste (silica gel particles) as fillers with 3% carbon fiber in unsaturated polyester resins on some properties such as flexural strength, flexural modulus, compressive strength, and thermal conductivity. Specimens composite was conducted by using the hand lay-up method and tested according to ASTM standards. The average particle size of the silica gel was 136.4 µm. Analyzed of the mechanical and physical properties that examined using SPSS with Tukey test and One Way ANOVA to know effect weight fraction of (carbon fiber/silica gel particle) on those properties, where statistical significance was set at P ≤ 0.05. From results, it is observed that the addition of silica gel particles up to 4% with 3% carbon fiber as strengthening materials to unsaturated polyester resins, leads to increase values the flexural strength, flexural modulus, compressive strength (293.00 ± 4.000 MPa), (5.4300 ± .04560 GPa), (124.67 ± 5.033 MPa) respectively, while the values of thermal conductivity decrease with addition 4% silica gel to (.0300 ± .02000 W/m.K°) compare with specimen unsaturated polyester (.3367 ±.03215 W/m.K°). The results of (SPSS) showed that the values (P) calculated from One Way ANOVA for flexural strength, flexural modulus, compressive strength, and thermal conductivity were (0.02, 0.001, 0.0001 and 0.04) respectively, less than (0.05) this indicates that the filler material has a clear effect on those properties that have been examined.In this research, investigate the effect of weight fraction (1%, 2%, 3%, 4%) industrial waste (silica gel particles) as fillers with 3% carbon fiber in unsaturated polyester resins on some properties such as flexural strength, flexural modulus, compressive strength, and thermal conductivity. Specimens composite was conducted by using the hand lay-up method and tested according to ASTM standards. The average particle size of the silica gel was 136.4 µm. Analyzed of the mechanical and physical properties that examined using SPSS with Tukey test and One Way ANOVA to know effect weight fraction of (carbon fiber/silica gel particle) on those properties, where statistical significance was set at P ≤ 0.05. From results, it is observed that the addition of silica gel particles up to 4% with 3% carbon fiber as strengthening materials to unsaturated polyester resins, leads to increase values the flexural strength, flexural modulus, compressive strength (293.00 ± 4.000 MPa), (5.4300 ± .04560 GPa), (124.67 ± 5.033 MP...

In this study, pineapple leaf fiber (PALF), kenaf fiber (KF) and PALF/KF/phenolic (PF) composites were fabricated and their mechanical properties were investigated. The mechanical properties (tensile, flexural and impact) of the PALF/KF/PF hybrid composites were investigated and compared with PALF/KF composites. The 3P7K exhibited enhanced tensile strength (46.96 MPa) and modulus (6.84 GPa), flexural strength (84.21 MPa) and modulus (5.81 GPa), and impact strength (5.39 kJ/m2) when compared with the PALF/PF and KF/PF composites. Scanning electron microscopy (SEM) was used to observe the fracture surfaces of the tensile testing samples. The microstructure of the 7P3K hybrid composite showed good interfacial bonding and the addition of KF improved the interfacial strength. It has been concluded that the 3P7K ratio allowed obtaining materials with better mechanical properties (tensile, flexural and impact strengths) than PALF/PF and KF/PF composites. The results obtained in this study will be used for further comparative study of untreated hybrid composites with treated hybrid composites.

Blends of polyethylene were foamed (593–782 kg/m 3 ) by compression molding. Their morphology was investigated to understand the effect of polymer molecular structure. It was found that the cell diameter distribution can be approximated by a truncated normal distribution. Torsion, flexural and tensile properties were also measured at different strain rates. It was found that the shear, flexural and Young's moduli of blends and their foams increase with increasing strain rate, while their normalized moduli are almost unchanged. We also confirm that thin skins have a definite effect on shear and flexural moduli, but are negligible on tensile moduli. Finally, normalized yield strength and strain are almost independent on strain rate while break strain and toughness increase with increasing molecular weight and decreasing strain rate.

The aim of the article is to analyze the influence of short coir, glass and carbon fiber admixture on the mechanical properties of fly ash-based geopolymer, such as: flexural and compressive strength. Glass fiber and carbon fibers have been chosen due to their high mechanical properties. Natural fibers have been chosen because of their mechanical properties as well as for the sake of comparison between their properties and the properties of the artificial ones. Fourth series of fly ash-based geopolymers for each fiber was cast: 1, 2, and 5% by weight of fly ash and one control series without any fibers. Each series of samples were tested on flexural and compressive strength after 7, 14, and 28 days. Additionally, microstructural analysis was carried out after 28 days. The results have shown an increase in compressive strength for composites with fibers—an improvement in properties between 25.0% and 56.5% depending on the type and amount of fiber added. For bending strength, a clear increase in the strength value is visible for composites with 1 and 2% carbon fibers (62.4% and 115.6%). A slight increase in flexural strength also occurred for 1% addition of glass fiber (4.5%) and 2% addition of coconut fibers (5.4%). For the 2% addition of glass fibers, the flexural strength value did not change compared to the value obtained for the matrix material. For the remaining fiber additions, i.e., 5% glass fiber as well as 1 and 5% coconut fibers, the flexural strength values deteriorated. The results of the research are discussed in a comparative context and the properties of the obtained composites are juxtaposed with the properties of the standard materials used in the construction industry.

ABSTRACTThis study develops two hybrid composites, both based on oil palm empty fruit bunch fiber (OPF) and nettle fiber (NTF) reinforced chemically functionalized high‐density polyethylene (CF‐HDPE). NTF and OPF show a 20% difference in their total holo‐cellulose contents. Two sets are developed. (i) (NTF/OPF)/CF‐HDPE (E) hybrid composites with equal (E) amounts of OPF and NTF, with a total of 10%, 20%, and 30% reinforcements. (ii) Three compositions of (OPF/NTF)/CF‐HDPE (V) hybrid composites have variable (V) amounts of OPF and NTF, with a fixed (F) total (T) (FT) 30% amount of the reinforcements. The objectives are to study the effects of (i) fiber/matrix adhesion and (ii) the total holo‐cellulose contents of reinforcements on the structure and properties of the hybrid composites. All the hybrid composites have been extruded, and their samples have been injection molded. The composites show reinforcement/matrix adhesion through ester and hydrogen bonds between them, as per the Palsule process. Relative to the matrix, all the hybrid composites have higher tensile and flexural modulus and strength. The comparative performance of these hybrid composites indicates that these properties are governed by the total holo‐cellulose contents of all the reinforcing fibers. Of all the hybrid composites, the V1, the (10/20)/70 (OPF/NTF)/CF‐HDPE hybrid composite, with the highest amounts of the total holo‐cellulose contents of its OPF and NTF combinations, shows the highest values of its flexural properties and also tensile properties.

The aim of this study was to assess the effect of printing orientation and water ageing on the flexural strength and flexural modulus of 3D printed resins for occlusal splints. Bar-shaped specimens were designed with dimensions of 64 × 10 × 3.3 mm according to ISO 20795-2:2013. Specimens were 3D printed with the Form 3B printer (Formlabs), using Dental LT Clear Resin (CL) or Comfort Resin (CO) (Formlabs), and 3 different printing orientations: as per manufacturer's recommendation (40° N = 20), parallel (0° N = 20), or perpendicular to the build platform (90° N = 20). To simulate intraoral ageing, half of the specimens per material and printing orientation (N = 10) were stored in distilled water at 37 °C for 30 days prior to testing. Specimens were tested in a three-point bending apparatus using a universal testing machine equipped with a 50 N load cell moving at a crosshead speed of 5 mm/min. Flexural strength (MPa) and flexural modulus (GPa) data were collected and statistically processed with separate analyses for unaged and aged specimens (Two-Way or One-Way ANOVA; Tukey test; p < 0.05). As for unaged specimens, both resin materials exhibited the highest flexural strength and modulus in the 90° orientation and the lowest values in the 40° orientation group. After water aging, all groups showed reduced flexural strength and modulus, with CO displaying up to 52% loss in flexural strength and values falling below ISO thresholds. CO consistently exhibited significantly lower flexural strength and modulus than CL, irrespective of aging.

Single-kenaf fiber-reinforced polymer composites are typically characterized by relatively low strength and stiffness properties that make them unsuitable for structural applications. However, they are lightweight, economical, and ecofriendly. This paper presents a study on the manufacturing and mechanical characterization of bidirectional kenaf (K) fiber-reinforced epoxy composites hybridized with carbon (C) fibers in various stacking sequences and the effects of hybridization on salient physical and mechanical properties. Single and hybrid fiber composites were fabricated utilizing the vacuum infusion molding technique. The density, tensile, flexural, and interlaminar shear properties in hybrid composites increased significantly when carbon fiber volume increased from 9% to 16%. Stacking sequences in a hybrid affected the mechanical properties of the composites. The highest tensile strength and modulus were shown by the seven-layer hybrid composite with an alternate K/C stacking sequence and C layers as skin layers, i.e., C/K/C/K/C/K/C, among all tested hybrid composites. Sandwich design in the hybrid (C2/K3/C2) had higher flexural strength (+300%), flexural modulus (+414%), interlaminar shear strength (+278%), lower water absorption (−46%), and thickness swelling (−30%) compared to single-fiber kenaf/epoxy composites. Density increased by 5% in hybrid composites. The highest fracture toughness (+134%) was achieved using the dual sandwich design structure hybrid (C/K2/C2/K2/C). The developed composite has applications in stairways, walkways, and bridges.

Characterization of injection-molded high-strength/high-stiffness thermoplastic hybrid materials containing thermotropic liquid crystal polymer (LCP), polyphenylene sulfide (PPS) with carbon fibers