Resin Infusion Research Articles

Enhancing the quasi-static strength of prosthetic socket made from composite laminates via hybridisation: Experimental and numerical study

This study aims to develop composite laminates for the manufacture of prosthesis socket with enhanced mechanical performance. Layered hybridisation of fabrics (i.e. glass, carbon, and Kevlar fabrics) is used to manufacture hybrid composite laminates by resin infusion via vacuum bagging method. The response of these materials to compression loading is investigated by using compression-loading testes and the load-bearing ability was examined by tensile strength tests. Moreover, finite element analysis has been carried out by using the Abaqus software to predict the compressive failure load and damage failure modes for all sockets samples. Experimental results revealed that the hybrid laminates exhibited more stability and higher absorbing energy compared to non-hybrid laminates during compressive loading tests. Furthermore, the hybridisation of fabrics layers can play key role for improving the tensile strength properties of hybrid composite laminates compared to composite laminates without hybridisation. The numerical simulation results of compressive failure load and damage failure modes are in accordance with experimental results qualitatively as well as quantitatively.

Mechanical performances of polyvinyl chloride (PVC) foam sandwich composites with glass cloth face-sheet

The mechanical performances of polyvinyl chloride (PVC) foam sandwich panels with different types of cores prepared by vacuum-assisted resin infusion process (VARI) were investigated. The flatwise, edge-wise compression, flexural and impact properties of three types of PVC sandwich panels of the prepared panels were performed. The results show that the mechanical performances of the foam sandwich composites can be enhanced due to the presence of polymer pins, and the impact properties appear slightly different at different stages. Due to the existence of pins, the energy absorption and impact properties of the sandwich panels are slightly reduced during the impact rebound phase, while the impact properties of the three sandwich panels do not change much during the impact penetrated phase. The contact surface and the cross-section through the damaged area were observed to analyze the failure modes of sandwich composites.

The Interconnection of Carbon Active Addition on Mechanical Properties of Hybrid Agel/Glass Fiber-Reinforced Green Composite.

Nowadays, the hybridization of natural and glass fiber has promised several advantages as a green composite. Nevertheless, their different characteristics lead to poor mechanical bonding. In this work, agel fiber and glass fiber was used as reinforcements, and activated carbon filler was added to the polymer matrix of a hybrid composite to modify its characteristics and mechanical properties. A tensile and bending test was conducted to evaluate the effect of three different weight percentages of activated carbon filler (1, 2, and 4 wt%). Vacuum-assisted resin infusion was used to manufacture the hybrid composite to obtain the high-quality composite. The results have revealed that adding 1 wt% filler yielded the most optimum result with the highest tensile strength, flexural strength, and elastic modulus, respectively: 112.90 MPa, 85.26 MPa, and 1.80 GPa. A higher weight percentage of activated carbon filler on the composite reduced its mechanical properties. The lowest test value was shown by the composite with 4 wt%. The micrograph observations have proven that the 4 wt% composite formed agglomeration filler that can induce stress concentration and reduce its mechanical performance. Adding 1 wt% filler offered the best dispersion in the matrix, which can enhance better load transfer capability.

A fast spatio-temporal temperature predictor for vacuum assisted resin infusion molding process based on deep machine learning modeling

A fast spatio-temporal temperature predictor for vacuum assisted resin infusion molding process based on deep machine learning modeling

In-situ monitoring of carbon fiber-reinforced plastic manufacturing using electrical resistance during infusion

Carbon fiber reinforced plastics (CFRPs) have been widely applied in various fields such as aerospace, vehicles, and civil infrastructure, even though their manufacturing time, labor, and cost are burdensome compared to other materials. However, studies on monitoring systems for composite manufacturing are limited. The spotlight is biased toward CFRP design and functional nanocomposites. Therefore, in this study, an in-situ monitoring system of a CFRP is proposed to investigate the vacuum-assisted resin infusion process in real time using electrical resistance changes. Specifically, two electrode types namely Cu tape and silver paste, were comparatively analyzed under several vacuum bag pressures. Resin impregnation was then investigated on the scale of a carbon fiber single tow and laminae. Impregnated resin increases the thickness of the laminae, thereby increasing the electrical resistance. Moreover, the curing behavior of the resin was correlated with changes in its electrical resistance so that the viscosity and degree of curing of the resin could be identified. The proposed method enables the detection of not only the resin front, but also the degree of curing.

Optimization of Characteristics Polymer Composite Reinforced Kenaf and Jute Fiber Using Taguchi-Response Surface Methodology Approach

ABSTRACT The use of composite materials with natural fiber reinforcement (CMNFR) has experienced rapid development in the automotive industry to apply synthetic materials that are expensive and not environmentally friendly. Biocomposite is a composite consisting of a polymer matrix and natural fiber reinforcement. Natural fiber materials are used as a substitute for conventional non-renewable reinforcing materials. This study uses the vacuum-assisted resin infusion (VARI) process to fabricate composites using woven kenaf and jute from natural fiber. The Taguchi experimental design method with L27 3 as an orthogonal array matrix was used in this research to obtain the optimum CMNFR fabrication parameters. Response Surface Methodology is used to obtain the optimal response value based on microstructural analysis. The factors used were NaOH treatment (4, 6, 8 wt%), water absorption test (6, 12, 24 hours), and fiber type (KF, JF, KF-JF). The study’s results found a combination of optimization of CMNFR manufacturing parameters using RSM, namely, A1B1C2 with a mean material strength of 0.241 J/mm2 (impact strength) and a combination of A1B3C1 parameters with a mean material strength of 94.8650 MPa (flexural strength). It was also found that the presence of contaminants and voids harmed the mechanical properties.

Effects of reactive and non-reactive tackifying agents on mechanical neat resin and composite performance for preforming processes and Liquid Resin Infusion (LRI) techniques

Preforming processes can be used for automated manufacturing of fiber reinforced polymers. Different technologies are used for processing of dry textile fabrics into 2D or 3D preforms. Due to missing tack of dry fabrics, auxiliary binder systems are used for fixation of the fabrics onto a substrate material and in order to achieve sufficient adhesion between layers. In this study, seven reactive and non-reactive tackifying agents have been dissolved in neat resin samples of three epoxy resin systems, showing different degrees of solubility and a variation on neat resin tensile properties (ΔσAVG = 20%) as well as a reduction on thermal properties (up to ΔTg = −18 °C). Subsequently, fiber reinforced polymers were manufactured using Liquid Resin Infusion techniques in order to characterize the influence of binder systems on water absorption (cs,max = 1.38 wt%) and Interlaminar Shear Strength (ILSS). It was shown that ILSS properties are negatively affected by non-reactive tackifying agents (up to −27%).

Influence of different structural parameters of 3D woven honeycomb composites on three-point bending behavior

In this study, various honeycomb preforms with different cell geometries were woven by changing the cell size, opening angle, free wall length, bonded wall length, and the number of layers keeping cell shape constant and composite thickness constant. The shape of the cells was altered by altering the pick numbers. E-glass tows of 600 Tex were used to produce fabric samples. All the constituent walls have the same construction and are woven with 2D plain fabric. Composite samples were created from honeycomb fabric and epoxy resin (matrix) using the VARIM (vacuum-assisted resin infusion method) technology. Three-point bending test was carried out for different cell geometries of 3D woven honeycomb composites. It was found that specific bending load is higher for a honeycomb structure with an opening angle of 60°, smaller cell sizes, small wall length, and for more layers keeping thickness and cell shape constant. Face wrinkling causes specimen failure in the following ways: localized buckling of the compressed face, debonding of the face sheet, and Mode 1 cell wall collapse in the region between the fixed support and load application.

Low-velocity impact behavior of 3D woven structural honeycomb composite

This paper describes the in-plane impact behavior of 3D woven honeycomb sandwich composites comprising glass fiber reinforced epoxy composite. In this study, 3D woven honeycomb structures with similar cell shapes were developed with different cell geometry by varying the cell size, free wall length, bonded wall length, opening angle, and the number of honeycomb layers keeping the overall thickness of the composite constant. The variation of cell geometry was carried out by changing the number of picks in the honeycomb walls. Composite samples were made using VARIM (vacuum-assisted resin infusion method) process. The behavior of the force-displacement curve and the energy-time relationship under impact loading of 100 J were analyzed. The total energy absorption was determined for different cell geometry and the number of layers of the honeycomb composites. The results showed that structural changes in honeycomb composite significantly affect the specific energy absorption. The specific energy absorption increases with a large cell size, less opening angle, higher wall length, and a greater number of layers.

Study of the Influence Factors for Ballistic Performance of Glass Fiber Reinforced Composites

The study prepares glass fiber reinforced composites through Vacuum Assisted Resin Infusion (VARI) process, selects glass fibers of different specifications, and studies the effects of lay-up mode, thickness, simulated normal incident angle, and temperature of fiber composites s on their ballistic performance. Results show that with slimmer fiber monofilament, reinforced materials perform better in ballistics; the lay-up mode has limited influence on ballistic performance; the relationship between thickness and ballistic performance is positively linear; and the relationship between normal incident angle and ballistic performance is parabolic. Compared with room temperature conditions, the ballistic performance of composites does not decrease and even increases slightly under low temperatures. Yet, the performance decreases sharply at high temperatures.

Ultrasonic welding of glass reinforced epoxy composites using thermoplastic hybrid interlayers

A glass fiber/polypropylene semi-impregnated lamina was added to an epoxy laminate, prior to the resin infusion, to overcome its limited weldability. Ultrasonic welding of the hybrid composite was conducted by varying welding pressure, time, and vibration amplitude, and using the thermoplastic layer as adjoining surface. Welded joints were analyzed by visual inspection, X-ray tomography, and lap shear testing. Welding time significantly influenced the lap-shear strength, the weld interface quality, and the process stability, promoting the proper intermixing of the thermoplastic layer and the formation of a weld area with strong adhesion. Amplitude and pressure, on the other hand, mostly affected the power absorption. Lower pressure, intermediate amplitude, and longer duration led to an improvement in the lap-shear strength (approximately 5 MPa in the best case). High strength was linked to high exposed-fiber surface area in the fracture surface, while its reduction was attributed to the presence of unwelded areas within the polypropylene interface. X-ray tomography highlighted the correlation between the occurrence of defects in the weld interface and the power profiles, where multiple peaks indicated the material friction and a progressive intermixing of the polymeric interlayer, while flattened profiles and lower peaks are associated to discontinuous and poorly adherent interfaces.

Preparation and Load-Bearing Capacity of Lattice Cell Warren Truss Slot Resin-Stiffener-Reinforced Foam Sandwich Material

This study optimized and proposed a Warren truss slot-hole structure with a double-sided, square shallow slot and vertical and horizontal corrugated symmetry, achieved with inclined holes based on the stability and a good bearing capacity of an inclined strut truss structure. The tetrahedral truss lattice cells were obverse and reverse-staggered in the central core of the structure. Compared with the double-sided, square shallow groove cylindrical straight hole, the resin consumption of the Warren truss slot holes was similar to that of a vacuum-assisted resin infusion; however, the external flat compression force of the Warren truss slot holes on the resin stiffener structure doubled, and its bending contact force increased by approximately 1.5 times. Furthermore, the resulting Warren truss-slotted resin structure exhibited a late failure time. Compared with the double-sided, square shallow groove cylindrical straight hole foam-core sandwich composite, the Warren truss slot resin-stiffener-reinforced sandwich composite exhibited an increase of 4.7 kN in the flat compression load, an improvement of ~40% in flat compressive strength performance, an increase of ~0.58 kN in the bending load, and an improvement of ~60% in the bending strength, demonstrating its better bearing strength performance.

Investigation of the resin infusion process and mechanical performance of carbon fiber reinforced plastic composites from recycled carbon fiber

The disposal of Fiber Reinforced Composites (FRCs) waste is becoming a very critical aspect, from both a technical and an economic point of view, due to the continuous increase of the production of such a class of materials. Thus, the possibility to produce new composites by employing recycled materials is a crucial aspect both to guarantee the circularity of the manufacturing processes and the reduction of costs. In this work, the manufacturing process, together with the performance of a carbon fiber-reinforced plastic (CFRP) laminate obtained by employing into sandwich structures a novel commercial recycled non-woven carbon fabric with an epoxy resin, have been investigated. The fabrication process based on the Resin Infusion under Flexible Tooling (RIFT) has been selected and performed in different conditions. The mechanical behavior of the resulting laminates has been investigated by quasi-static tensile, and flexural characterization, to evaluate both the optimal conditions for the process, and the possible anisotropy of the product. Moreover, thermogravimetric analysis (TGA) was applied to complete the post-processing characterization of the resulting laminate by determining the actual carbon fibers (CFs) content, thus, to validate the reproducibility of the manufacturing process. The laminates obtained by the RIFT method exhibited good mechanical properties and isotropy if cross-ply stratification is adopted. The use of recycled CFs allows high sustainability and reduced cost for the composites, making the RIFT method investigated a scalable process and the so-manufactured products a valid candidate for numerous applications.

Effects of vacuum infusion configuration on homogeneity of glass fiber reinforced polymer composites for automotive components

In this study, the effects of vacuum infusion configuration on the homogeneities of glass fiber reinforced vinyl ester composites have been evaluated. Three different sizes of samples (100x100, 500x500, and 1000x1000 mm) were fabricated. Three different configurations were used to fabricate the samples. The first two configurations had one inlet, while the third configuration had two inlets for resin infusion. Thickness variations and hardness (Shore D) measurements were performed to determine the homogeneities of the samples. The results revealed that, for small size samples, the configurations have no obvious effect on the homogeneity of the samples, both in terms of thickness variations and hardness values. However, for larger samples, the configuration where the resin is introduced into the preform in the center of the component showed better homogeneity than other configurations. Even a better distribution is assessed with the introduction of the resin in the center of the sample, although this configuration also resulted in thickness swellings in the central areas of the sample. The thickness swellings were observed around the inlet areas for all configurations. The study shows that the resin flow in the center of the component is preferable but thickness swelling must be considered when dimensional tolerances are critical.

Static strength of lower-limb prosthetic sockets: An exploratory study on the influence of stratigraphy, distal adapter and lamination resin

Knowledge about the mechanical properties of lower-limb prosthetic sockets fabricated with resin infusion lamination and composite materials is limited. Therefore, sockets can be subject to mechanical failure and over-dimensioning, both of which can have severe consequences for patients. For this reason, an exploratory study was conducted to analyze the effect of stratigraphy (layup and fibers), matrix (resin) and mechanical connection (socket distal adapter) on socket static strength, with the objectives of: 1) implementing a mechanical testing system for lower-limb prosthetic sockets based on ISO 10328:2016 and provide the mechanical design of the loading plates, 2) apply the testing system to a series of laminated sockets, and 3) for each type of distal adapter, identify the combinations of stratigraphy and matrix with acceptable strength and minimum weight.Twenty-three laminated sockets were produced and tested. Sixteen met the required strength, with ten exhibiting an excessive weight. Among the remaining six, four combinations of stratigraphy and resin were identified as best option, as they all overcame ISO 10328 P6 loading level and weighted less than 600 g. The selected stratigraphies had limited or absent amount of Perlon stockinettes, which seems to increase weight without enhancing the mechanical strength. Sockets based on Ossur MSS braids and connector show the best compromise between strength and weight when the amount of carbon braids is halved.

Durability Study of Glass/Carbon Hybrid Composites Immersed in Seawater for Marine Application

The hybridization of carbon fiber (CFRP) and glass fiber (GFRP) composites is required to overcome the disadvantages of GFRP composites and their commercial feasibility for marine applications. This study was conducted on a hybrid glass/carbon composite with a vinyl ester matrix made by vacuum-assisted resin infusion process with a stacking sequence of [GCG2CG2C] s. Composites are immersed in natural seawater for up to 6 months. The maximum weight gain of e-glass/carbon hybrid composite is 0.79%. The results showed that the tensile, shear and compressive strengths of the glass/carbon hybrid composite after immersion in natural seawater decreased to 19%, 13%, and 50%, respectively. The decrease in compressive strength is the highest compared to others. It indicates that compressive strength should be of more significant concern for marine environmental applications. SEM analysis exhibited that seawater absorption causes the matrix, fiber, and fiber/matrix interface degradation. It is indicated by the absence of a firm matrix fracture surface, the number of fractures in the thread, the presence of fiber/matrix debonding, and fiber pull-out in the specimen after immersion in seawater. It is the cause of the decrease in the mechanical properties of the hybrid composite.

Experimental and Numerical Investigations on the Tensile Behaviour of Bamboo-Glass Fibres Hybrid Reinforced Polymer Composites

The paper presents the experimental and numerical investigations of the tensile properties of bamboo-glass fibres hybrid reinforced unsaturated polyester composites. The stacking configuration was GGBBBGG and GBGBGBG, with G and B, respectively denoted BFRP and GFRP. The hybrid composites were manufactured using a resin infusion technique. It was found that the tensile strength of the GGBBBGG was higher than that of GBGBGBG, but the elastic modulus seemed not significantly different. Hence, the glass fibres positioned at the outer layer (as skin of a sandwich composite) gave the better tensile properties than that of the alternating configuration. Numerical work utilising an extended finite element method (XFEM) had been undertaken, and a reasonable agreement on the failure load was found between the numerical and experimental results. However, the numerical load-displacement curves were underpredicted, which might be due to the load train of the testing equipment and also, the model did not include delamination within the layers.

Experimental Study of Sandwich Strength Materials Made from Banana Fiber, as Advance Materials of the Unmanned Mine Sweeper (UMS) Hull

Mine countermeasures (MCM) is a sea operation that is very risky for personnel and material losses. The development of mine technology with the discovery of modern digital mines technology currently makes mine warfare strategies change, namely by relying on the unmanned minesweeper (UMS) as a mine detector, to mitigate the impacts and risks of sea mines on naval operations. UMS vessel size is 4.8m LoA, speed 2.57m/s and beam 2.24m. The main requirements for UMS are low magnetic, low vibration, and low hydrostatic. In this study, the author will make a sandwich material made from banana fibre as an Unmanned Mine Sweeper gastric material. The choice of banana fibre is because in addition to low magnetic, its availability is very abundant in Indonesia and the price is relatively cheaper than kevlar fibre. This study uses the technique of manufacturing vacuum assessed resin infusion (VARI). Then the strength test will be carried out with a tensile test, impact test and hardness test using the ASTM standard and compared with wood and fibre materials. The test results show that abaca banana fibre is capable of being used as an unmanned minesweeper hull material.

Mechanical and optical performance evaluations of embedded polyimide and PEEK coated distributed optical sensors in glass fibre reinforced composites with vinyl ester resin systems

Embedded optical fibre sensors (OFSs) offer the potential to monitor the internal strains at various stages during the manufacturing and service life of fibre-reinforced polymer (FRP) composite structures. Various aspects associated with the embedment of OFSs, such as integration, material compatibility, and sensing performance of the embedded sensor needs to be investigated to develop reliable OFSs based internal sensing platform for composite structures. In this study, Polyimide (PI) and Polyether ether ketone (PEEK) coated optical fibres (OF) were embedded into glass fibre-reinforced polymer (GFRP) composites to evaluate four important aspects associated with the embedment of OFs, which include; i). Structural integrity of the OFs against chemical reactions from vinyl ester resin and its additives through immersion testing, ii). Methods of integrating the OFs into layered glass fibres for the vacuum resin infusion manufacturing process, iii). Sensing performance of the embedded OFs during manufacturing and structural testing (tensile and compressive), and iv). Internal structural integrity of the embedded OFs and the host composite structure using X-Ray micro-computerised tomography technique (μ-CT). The results from the immersion testing and manufacturing process monitoring showed that both PEEK and PI coated OFs can resist the chemical and mechanical stresses caused by resin polymerisation during curing process. The subsequent mechanical testing showed a similar sensing performance by the PI and PEEK coated OFs. Under tensile loads, the OFs monitored the tensile strain distribution up to 7,000 με and compressive strain distribution up to −1,200 με under flexural loading without compromising their optical performance. Finally, the μ-CT scanning results had shown a minimal structural deterioration of the embedded OFs and host composite structure. The outcomes from this detailed experimental investigation on the embedment of OFS in GFRP structures provided useful information towards the integration and performance of optical sensors in composite structures.

Comparative study of microwave and thermal curing processes in terms of temperature characteristics and mechanical performance of carbon fibre composites

In this work, carbon fibre composites were manufactured using vacuum-assisted resin infusion microwave curing and vacuum-assisted resin infusion thermal curing processes. The microwave curing as well as thermal curing heat generation mechanisms were studied along with the thickness of the carbon fibre composites. Microwave power levels of 180 W, 360 W, 540 W and 720 W and thermal power levels of 1000 W and 2000 W were used. The K-type thermocouples were placed between the layers of the carbon fibres to record temperature profile during the curing process. The role of power levels was studied on thermal gradient along with the thickness of composites, which influences the curing kinetics. The composites were evaluated for their degree of cure, density and void percentage. Mechanical performance of the composites was assessed in terms of uniaxial tensile test, three-point bend test and interlaminar shear strength test. It was observed that microwave-cured composites were manufactured with less time and energy compared to thermal curing. The mechanical performance of microwave-cured composites was also better than thermally cured composites.