Type Of Reinforcement Research Articles

Toughening of self-reinforced PLA films using PLA nanofiber mats and oriented PLA tapes as interlayers

Self-reinforced poly(lactic acid) composite (SRPLA) offers advantages in terms of convenient recycling due to its mono-material nature, potential biodegradability, and biocompatibility. Moreover, SRPLA has shown the ability to overcome the inherent brittleness of PLA. To deepen our understanding of how different types of reinforcements and process parameters can affect tensile properties, particularly tensile toughness, SRPLA has been prepared based on oriented tapes (ot-SRPLA) as well as nanofiber mats (nf-SRPLA) using a film-stacking and hot-compaction approach. A considerable improvement was observed in tensile strength, modulus, and toughness at the optimum consolidation temperature and time. Specifically, the tensile toughness of nf-SRPLA increased approximately threefold at a very low nanofiber loading of 0.56 wt%, while the toughness of ot-SRPLA more than doubled at a tape mass fraction of 36 wt%. In terms of toughening mechanisms, the presence of the nanofibers slowed down crack propagation through crack branching, deviation, and fiber bridging in nf-SRPLA, whereas the predominant toughening mechanisms were interlayer debonding and tape pull-out for ot-SRPLA.

Investigation of punching shear performance in concrete slabs reinforced with GFRP and synthetic fibers: An experimental study

The punching shear resistance mechanism of reinforced concrete slabs with glass fiber-reinforced polymers (GFRP-RC) is weaker than that of steel-RC slabs. The reduced shear strength and modulus of elasticity of GFRP reinforcement which led to greater tensile strains of the reinforcement and shallower compressive zone reduce the contribution of concrete in compression, aggregate interlocking, and dowel action to the punching shear mechanism. This condition results in reduced capacity and a higher likelihood of catastrophic failure compared to their steel-RC counterparts. To address this weakness of GFRP-RC, this paper aims to examine the punching shear performance of GFRP-RC slabs and explore the potential improvements through the incorporation of synthetic fibers. A total of 11 two-way slabs having a dimension of 1000 × 1000 mm with a thickness of 80 mm were tested under punching shear load and the effect of several types of fiber (polypropylene (PP) and (polyvinyl alcohol (PVA)), fiber content (0, 0.5%), reinforcement ratio, and reinforcement type (steel and GFRP) was investigated. The slabs’ behavior was assessed by considering crack width, deflection performance, the mode of failure, and the overall load-bearing capacity. The findings indicated that the influence of fibers was more noticeable in GFRP-RC slabs compared with steel-RC counterparts. Moreover, the fibers were found to effectively reduce deflections and crack widths. The results particularly showed the superior performance of PVA fibers in improving the capacity of the two-way slabs, whereby the addition of 0.5% PVA fibers led to the punching shear capacity increase of 44–51%. The findings of this study offer a better understanding of the punching shear behavior of slabs reinforced with GFRP reinforcement and synthetic fibers.

Bond performance of FRP bar reinforced concrete under monotonic load and fatigue effect

In order to investigate the bonding properties of FRP-reinforced concrete under different loads, a series of FRP-reinforced concrete specimens were subjected to pull-out tests. Three types of reinforcement were used in the experiment: ordinary steel reinforcement, carbon fiber reinforcement (CFRP), and glass fiber reinforcement (GFRP). Pull-out tests were first conducted under monotonic load to determine the effect of concrete strength and reinforcement diameter on the bond performance of FRP bar-reinforced concrete and steel-reinforced concrete. The investigation of the variation of bond performance under different reinforcement materials was made. Second, a fatigue test was done, followed by further pull-out tests to get the bond stress-slip curve between concrete and reinforcement, and the influence of fatigue action on the bond stress-slip curve was further examined. The formulae to calculate the stress were developed, which can be applied to determine the bond failure pattern, bond strength, and bond-slip curve.

Flexural Behavior of RCC Beam Using Confined Reinforcement with Helical Stirrups

In the present condition the cost of construction goes on increasing due to usage of steel. In order to improve the tensile strength in concrete and reducing the usage of steel, a new type of reinforcement is essential for making an economical building. The main objective of our project is to reduce the usage of steel by providing helical stirrups in the reinforcement recommended as per IS 456:2000. By this method of reinforcement, we can achieve flexure in reinforced concrete beams which opposes conventional method of reducing the neutral axis depth of the beam. The under reinforced section of the beam can be achieved by this method of helical stirrups in the reinforcement. Steel is introduced in the tension zone to take the tensile stress, but as strength of concrete is ignored in tension zone with respect to compression zone. The objective of this research is to investigate the behavior of singly, doubly and confined reinforced beams. Ultimate load, deflection load, compressive stresses and tensile stresses were compared with the controlled plain reinforced helical stirrups beams. Single and double reinforced concrete beams were cast and tested for this purpose of investigation. The results obtained have indicated that enhanced the strength of concrete.

Mechanical properties enhancement of 3D-printed HA-PLA composites using ultrasonic vibration assistance

ABSTRACT 3D-printed HA-PLA composites have attracted much attention because of their excellent biodegradability and osteointegration properties. However, HA particles negatively affect the mechanical properties of the composite parts. In this study, ultrasonic vibration-assisted 3D printing was used to improve the mechanical properties of HA-PLA composite specimens, and the effects of different infill angles and ultrasonic vibration power on the mechanical properties were investigated. The results demonstrated that the degradation and anisotropy of the mechanical properties of HA-PLA composites were alleviated by the use of ultrasonic vibration. By applying the ultrasonic vibration, the tensile and flexural strengths of the 20 wt% HA-PLA specimens fabricated with a 90° infill angle demonstrated the largest improvement of 104.3% and 112.7%, respectively. The high-frequency ultrasonic vibration waves promoted the spreading and fusion of the extruded materials, thereby reducing overlapping voids within the specimens and improving the interface bonding strength, also facilitated the refinement and dispersibility of the HA particles, which inhibited the formation of stress concentrations within the specimens and ultimately improved the mechanical properties. The printing process developed in this study can also be adapted to other particle (or other reinforcement types) reinforced composite to improve their mechanical performance.

Article of RILEM TC 292-MCC: bond behaviour of textile-reinforced concrete—a review

Textile-reinforced concrete (TRC) has gained a lot of attraction in recent years. Adequate bond between the phases in this system allows to transfer high loadings, thus enabling high performance. The terminus textile reinforcement, however, comprises many different types of fabrics, which differ in their chemical composition, geometry, surface properties etc., and thus exhibit substantially different bond properties. In the course of RILEM’s Technical Committee 292 work on TRC it was found that a comprehensive understanding of the complex interactions between individual parameters is still lacking. This is amplified by the fact that different types of textile reinforcement are preferably used in different regions of the world. This paper therefore attempts to compile findings from literature on the bond in TRC. The database used was created in the course of the TC work. Additional papers of relevance were identified by scanning scientific web databases. The different influencing parameters are given in this paper in a hierarchical order, starting from the level of the individual constituents (filament and matrix) to impregnated fabrics and the influence of textile manufacturing and architecture on the bond. Finally, by mapping all the cited literature used in this paper based on grouped keywords the complex intercorrelations are visualised.

Investigation of the effects of volume fraction, aspect ratio and type of fibres on the mechanical properties of short fibre reinforced 3D printed composite materials

AbstractMechanical behaviour of 3D-printed composite parts is affected by the volume fraction, aspect ratio and type of fibre reinforcement. Although in the literature experimental approaches have been used to characterise the effects of the above factors on the mechanical properties of 3D printed parts, time and cost of the manufacturing process as well as the uncertainty associated with a large number of experimental techniques are the key issues. This study aims to address these challenges by developing a methodology based on a multi-scale Finite Element (FE) analysis of representative volume element (RVE) of 3D printed composite parts to predict the effective orthotropic properties. To account for the effects of fibre features, RVEs were modelled considering variables of volume fraction, aspect ratios and type of short fibres. To study the main and interaction effects of the above variables on the mechanical properties of 3D printed composite parts, a structured approach based on the Design of Experiments is used. The FE stress analysis of the RVE provides an understanding about the potential failure modes such as interfacial debonding between fibres and matrix, interlayer and intralayer delamination that may occur in load-bearing 3D printed composite parts. The FE computed mechanical properties are validated against experimental data through a series of mechanical testing of flexure, Iosipescu, and short beam shear which were conducted in conjunction with the Digital Image Correlation technique. As a result, certainty is obtained in using the proposed approach for a fast iterative design of 3D printed composite parts prior to industrial applications.

Impact of the Curing Temperature on the Manufacturing Process of Multi-Nanoparticle-Reinforced Epoxy Matrix Composites.

This study aims to analyze the effect of the curing temperature of nano-reinforcements during the manufacturing process on the mechanical properties of composites involving graphene (GNP), carbon nanofibers (CNFs), and a hybrid mixture of these two nanoparticles. In this context, the type of nanoparticles, their content, their type of resin, and their hybridization were considered. The results showed that both nanoparticles increased the viscosity of the resin suspension, with an increase of between 16.3% and 38.2% for GNP nanoparticles and 45.4% and 74% for CNFs depending on the type of resin. Shrinkage was also affected by the addition of nanoparticles, as the highest results were obtained with GNP nanoparticles, with a 91% increase compared with the neat resin, and the lowest results were obtained with CNFs, with a decrease of 77% compared with the neat resin. A curing temperature of 5 °C promoted the best bending and hardness performance for all composites regardless of the type of resin and reinforcement used, with improvements of up to 24.8% for GNP nanoparticles and 13.52% for CNFs compared with the neat resin at 20 °C. Hybridization led to further improvements in bending properties and hardness compared with single-reinforcement composites due to a synergistic effect. However, the effectiveness of hybridization depends on the type of resin.

Conditioned overconsumption is dependent on reinforcer type in lean, but not obese, mice.

Associative learning can drive many different types of behaviors, including food consumption. Previous studies have shown that cues paired with food delivery while mice are hungry will lead to increased consumption in the presence of those cues at later times. We previously showed that overconsumption can be driven in male mice by contextual cues, using chow pellets. Here we extended our findings by examining other parameters that may influence the outcome of context-conditioned overconsumption training. We found that the task worked equally well in males and females, and that palatable substances such as high-fat diet and Ensure chocolate milkshake supported learning and induced overconsumption. Surprisingly, mice did not overconsume when sucrose was used as the reinforcer during training, suggesting that nutritional content is a critical factor. Interestingly, we also observed that diet-induced obese mice did not learn the task. Overall, we find that context-conditioned overconsumption can be studied in lean male and female mice, and with multiple reinforcer types.

Active vibration control of piezoelectric multilayers FG‐CNTRC and FG‐GPLRC plates

AbstractThis study investigates the active vibration control of multilayer Functionally Graded Carbon NanoTube Reinforced polymer Composite (FG‐CNTRC) plates and multilayer functionally graded graphene platelets reinforced polymer composite (FG‐GPLRC) plates covered with a piezoelectric layer (PZTG1195N) serve as both actuators and sensors. The plate's heart is supposed to be reinforced nonlinearly using both types of reinforcement. Active vibration control of plates under uniform load was achieved by utilizing a velocity feedback control algorithm with a specific gain value. The finite element method is employed to analyze both the static and dynamic behavior of a square plate discretized into 9‐node quadratic finite elements with 5 ° of freedom per node. The material properties are assumed to change across the thickness direction following a power law distribution, exhibiting various patterns: Uniform Distribution (UD), as well as Functionally Graded types X, O, and A (FG‐X, FG‐O, and FG‐A). The geometrical nonlinear equations are solved by the Newmark integration method. This work begins by validating the natural frequencies of a Functionally Graded (FG) composite plate reinforced with four different distributions of Nano‐filler and then aims to show the effect of the nonlinear distribution of nanofillers on the plate's stiffness. The Results obtained after the execution of a developed code highlight the significance of employing a nonlinear distribution of nanofillers to attenuate vibrations.Highlights FG composite and sandwich plates reinforced with GPLs and CNTs. Effect of nonlinear nanofillers distribution of reinforcement on free and forced vibration. The ability of the nonlinear distribution of nanofillers to attenuate forced vibrations.

Tensile assessment of woven CFRP using finite element method: A benchmarking and preliminary study for thin-walled structure application

Abstract Carbon-fiber-reinforced polymers (CFRPs) are a composite material popular for thin-walled structure applications because of their advantages over other materials. In this study, numerical simulation analysis based on the finite-element method to identify the tensile behavior of CFRP woven material has been carried out. The method used has been verified and validated using a benchmarking procedure with the results of previous research. Errors in the simulation results are less than 10%, indicating a valid method that can be used for further research. The stress–strain distribution of each layer, the effect of ply orientation on tensile strength, the comparison of failure criteria used, and the comparison of several types of reinforcements often used have been investigated. The results showed that the characteristics of each inner layer received tensile loading visualized in the form of stress strains. Choosing the right layer angle on CFRP woven can affect the performance and strength of the material. Failure criteria that are appropriate to specific application conditions are important. Puck criteria can be used for simple applications, which require only the analysis of the main stresses in the material. Tsai–Hill and Tsai–Wu criteria can provide more accurate predictions and are better suited for loading conditions and more complex material types. Carbon fiber has better characteristics when compared to S-glass and E-glass.

An experimental study on the strength values of resin added sand samples with different types of fiber reinforcements

In this study, uniaxial compressive strength values of a sand type soil reinforced with polypropylene fiber and silicate-based resin additives with different amounts were investigated. Micro grid fiber (MGF) was tested as a new polypropylene fiber additive in the experiments to compare it with a widely used polypropylene fiber type geosynthetic product used in soil fill improvement applications. According to the findings obtained from the uniaxial compressive strength (unconfined compressive strength) tests, it was determined that the new MGF type fiber usually increased the strength values at higher rates in comparison with the conventional fiber product. As another outcome, it was found that target strength values can be supplied by using less resin amounts for the specimens with fiber additives. It was determined that proper strength improvements can be obtained more economically by the fiber additive use together with the resin, rather than the resin added mixtures without the fiber.

Thermal and Mechanical Performance of 3-Phase Polymer Composite Panels for Structural Applications

The objective of this study is to establish a conceptual framework for fiber-reinforced polymer composite (FRPC) panels designed for structural purposes through the incorporation of a third phase (fillers). The present investigation was aimed to design and fabricate 3-phase polymer composite panels that offer enhanced thermal insulation and strength while maintaining low material and labor expenses. Two types of fibrous reinforcements (jute fabric and glass fabric) of different origins were used as reinforcement; polypropylene (PP) was used as the matrix, and microcrystalline cellulose (MCC) was used as particle reinforcement material. The composite materials were fabricated with different MCC concentrations (0, 2 wt%, and 4 wt%), using a hot compression molding technique. It was found that MCC helped to enhance the mechanical performance of the composite panels, while the thermal conductivity showed a slight reduction due to lower concentrations of MCC used. For polypropylene/glass (PPG) composites, thermal conductivity was reduced from 0.214 to 0.193 W/m·K by the addition of 4% MCC fillers. Similarly, for polypropylene/jute (PPJ) composites, it was reduced from 0.14 to 0.126 W/m·K by 4% MCC fillers. The Charpy impact strength of both PPG and PPJ composites was enhanced by the addition of fillers, and the effect was more significant in the case of PPG (increased from 24.83 to 43.98 kJ/m2 for 4% fillers). Cost analysis of the composite panels was also done, showing PPJ panels to be slightly cheaper as compared to PPG. The findings indicate that the developed composite panels have the potential to serve as partitioning as well as the outer shield of the building due to their effective thermal and mechanical properties.

Structural Behavior of Circular Concrete Columns Reinforced with Longitudinal GFRP Rebars under Axial Load

This paper presents experimental and theoretical assessments of the structural behavior of circular steel fiber-reinforced concrete (SFRC) columns reinforced with glass fiber-reinforced polymer (GFRP) bars subjected to a concentric axial compressive load. Laboratory experiments were planned to evaluate and compare the effect of different design parameters on the structural behavior of column specimens based on experiments and finite element (FE) analysis. The experimental variables were (i) concrete types, i.e., conventional concrete (CC) and fiber-reinforced concrete (FC), (ii) longitudinal reinforcement types, i.e., steel and GFRP bars, and (iii) transverse rebar configurations, i.e., tied and spiral with different pitches. Sixteen column specimens were fabricated and categorized into four groups with respect to rebar configurations and concrete types. The results showed that the failure modes and cracking patterns of those four column groups were comparable, particularly in the pre-peak branches of load-deflection curves. Even though the average ultimate load of the columns with longitudinal GFRP bars was 17.9% less than that with longitudinal steel bars, the ductility index (DI) was 10.2% greater than their counterpart on average. The addition of steel fibers (SF) to concrete increased the axial peak load by up to 3.1% and the DI by up to 6.6% compared to their counterpart CC columns without SFs. The DI of specimens was increased by higher volumetric ratios (up to 12%) and spiral types (up to 5.5%). The concrete damage plastic (CDP) model for FC columns was updated in the finite element software ABAQUS 6.14. Finally, a new simple equation was theoretically proposed to predict the axial capacity of specimens by considering the inclusion of longitudinal GFRP rebars, volumetric ratio, and steel spiral/hoop ties. Good agreement between the proposed model predictions and the experimental/numerical results was observed.

Experimental Study Of Simple Cyclic Testing On Reinforced Beam Using Fiber Reinforced Polymers (FRP)

The geographical location of Indonesia on the Ring of Fire makes it prone to earthquakes. Frequent earthquakes cause failures in construction. Construction failures must be repaired to restore the strength of the structures to their original or even higher levels. One type of structural reinforcement is Fiber Reinforced Polymers (FRP). FRP can enhance the strength of beams damaged by earthquakes, alter the structural failure mode, increase load-carrying capacity, and prolong plastic hinges in beam elements. This study recommends using FRP to reinforce concrete structures, particularly beams. The first stage of the research involves experimental testing on a prototype not wrapped with FRP. After reaching peak strength and experiencing failure, then the prototype is covered with FRP. Subsequently, the prototype is retested until it gets peak strength and experiences failure again. Both specimens are subjected to monotonic loading, which is simulated as cyclic loading. Data processing is performed by analyzing the results of the experimental testing on both prototypes. The processed data includes crack patterns in the beams, cyclic load capacity, displacement, strain of concrete, strain in the primary reinforcement, and strain in the stirrup reinforcement.

Effect of different types of reinforcement denture base materials on implants retained overdenture

Effect of different types of reinforcement denture base materials on implants retained overdenture

Design and preparation of WBX/Al composites for nuclear radiation protection

As the utilization of nuclear energy continues to expand, there is a growing focus on the development of lightweight and efficient nuclear shielding composites. In this paper, novel WBX/Al (x = 1, 2, 4) composites were designed based on shielding performance. The effects of reinforcement type, volume fraction, and material thickness on the 60Co and 137Cs γ-rays, fast and thermal neutron shielding performances were simulated. The results show that WB/Al composites offer better development potential compared to WB2/Al or WB4/Al composites. Additionally, a predictive model for the γ-ray shielding effectiveness of WB/Al composites, based on the areal density of tungsten, was proposed. The fabrication process involved mechanical ball milling and spark plasma sintering to fabricate 30 vol% WB/Al composites, with optimization of ball milling time, sintering temperature, and holding time. As a result, a novel nuclear radiation protection composite with uniform composition, a relative density of 97 %, and flexural strength of 527 MPa was acquired.

Physical and 3D numerical modelling of reinforcements pullout test

This paper reports results of laboratory and 3D numerical modeled pull-out tests with steel ladders and polymeric strip reinforcements. These types of reinforcement are commonly used in reinforced soil walls constructed with concrete facing elements. Laboratory pull-out tests are required to determine accurate and realistic pull-out strength values considering the interaction of specific reinforcement and backfill materials under different confining pressures (i.e., trying to simulate the different reinforcement layer arrangements and load conditions in actual reinforced soil walls). International design Codes for reinforced soil walls provide default values for pull-out strength. However, in many cases, default values are too conservative and/or are not strictly specified for particular reinforcement types. Pull-out tests can be difficult and expensive to perform, thus not being common nor worth for the vast majority of reinforced soil wall projects. Consequently, calibrated numerical models can be useful to predict pull-out response under site-specific conditions, and provide further understanding of the mechanisms involved in the soil-reinforcement interaction. Details of the numerical approach, including relevant aspects of the soil-reinforcement interfaces, are described. Examples of calibrated numerical predictions for pull-out loads, displacements, and soil-dilatancy effects are presented. The influence of reinforcement, soil and interface stiffnesses is shown. Numerical results provide useful insight for future modelling works of the complex interaction between type-specific backfill materials and reinforcement element, relevant for investigation and/or practical design of reinforced soil walls.

Sandwich structures of aluminium skins and egg-box-shaped cores made with biobased foam and composites

Sandwich panels composed of aluminium skins and egg-box-shaped cores made with natural fibre composites are tested in three-point bending and evaluated statistically and through failure analysis. The corrugated cores are assessed with filled bio-based foam. In order to produce these sandwich panels, preliminary investigations on natural fibre composites, and their use as egg-box-shaped structures are conducted. A full factorial design is performed to assess the effects of fibre reinforcement (sisal or coir) and polymer matrix types (epoxy or castor oil) on the physical-mechanical properties of flat composite laminates. These composites are also used to manufacture the egg-box shaped structures in different sizes, which are characterized under compression testing. A new analytical approach called RJS Method is used to determine the flexural and shear modulus of the proposed sandwich panels and estimate the shear contribution. The results reveal that flat laminated composites and their corresponding egg-box shaped cores, composed of sisal fibres and epoxy polymer, achieve higher absolute and specific mechanical properties. The corrugated core also leads to sandwich panels with higher mechanical properties, increasing the skin and core shear stresses by up to 60 and 76%, respectively, compared to the coir fibre castor-oil cores. The failure modes of the sandwich panels are limited to the core and are chronologically established through foam tearing, foam-egg-box shaped composite debonding, and final egg-box cell-wall flattening. The findings demonstrate that the sandwich panel based on egg-box shaped core made from natural resources is feasible for scaling up in different structural applications.

Review of Machine learning: Views, Architectures or Techniques, Challenges and Future guidance and Real-world applications

In this digital world, the data is wealth, this data is analyzed, developed and applied to specific applications using some well-developed algorithms known as Machine learning (ML). Machine learning algorithms are supervised, unsupervised, semi-supervised and reinforcement types. Deep learning (DL) is also a method of analyzing the data on a large scale. Deep learning is a further subdivision of The subsection of ML is deep learning and measures a particular type of learning that involves the use of artificial neural networks (ANN). This paper provides group of different machine learning terminologies for quick reference. This study is important to focus on different machine learning techniques and their connection in various real-world applications such as smart cities, cyber security, healthcare, agriculture and intelligent transportation systems. In this paper, machine learning concepts, different types of architectures, the challenges, various real world applications are discussed.