Application Of Fiber Reinforced Polymer Composites Research Articles

Compressive Behavior and Analytical Model of Ultra-Early Strength Concrete-Filled FRP Tube With Zero Curing Time

Fiber-reinforced polymer (FRP) has been widely used in civil engineering due to its light weight, high strength, convenient construction, and strong corrosion resistance. One of the important applications of FRP composites is the concrete-filled FRP tube (CFFT), which can greatly improve the compressive strength and ductility of concrete as well as facilitate construction. In this article, the compressive performances of a normal concrete-filled FRP tube (N-CFFT) column with 5-hour curing time and an ultra-early strength concrete-filled FRP tube (UES–CFFT) column with zero curing time were studied by considering the characteristics of rapid early strength improvement of ultra-early strength concrete and the confinement effect of the FRP tube. Monotonic axial compression tests were carried out on 3 empty FRP tubes (FTs) without an internal filler and 6 CFFT (3 N-CFFTs and 3 UES-CFFTs) specimens. All specimens were cylinders of 200 mm in diameter and 600 mm in height, confined by glass fiber–reinforced polymer (GFRP). Test results indicated that the compressive bearing capacity of the specimens increased significantly by adopting the ultra-early strength concrete as the core concrete of the CFFT, although the curing time was zero. It was also shown that the compressive behavior of the UES–CFFT specimens with zero curing time increased significantly than that of the N-CFFT specimens with 5-hour curing time because the former was able to achieve rapid strength enhancement in a very short time than the latter. The ultimate compressive strength of UES–CFFT specimens with zero curing time reached 78.3 MPa, which was 66.2 and 97.2% higher than that of N-CFFT with 5-hour curing time and FT specimens, respectively. In addition, a simple confinement model to predict the strength of UES–CFFT with zero curing time in ultimate condition was introduced. Compared with the existing models, the proposed model could predict the ultimate strength of UES–CFFT specimens with zero curing time with better accuracy.

Fiber-Reinforced Polymers in Freeform Structures: A Review

This article is a survey discussing the application of fiber-reinforced polymer composites in freeform structures and their impact on the design and shape generation process. The analysis of case studies showed that the use of FRP composites not only helps to overcome some challenges in the construction of objects with complex geometry, but also creates brand new types of structures and design approaches. On the other hand, there is a problem—although FRP materials are frequently used in construction, the shapes of structures and design methods are often traditional and are simply copied from materials such as wood, concrete, and steel. FRP composites have been applied in civil engineering for several decades, since the 1960s, as building envelopes, façade skins, load-bearing structures, and internal and external reinforcement. The article aims to analyze this accumulated experience and to explore the role of FRP materials in the design of buildings with free, complex, fluid, and organic shapes. A new classification of freeform composite structures is proposed. They are classified in this article according to the methodology applied at the conceptual design stage: structures created by using a geometric approach, a form-finding (equilibrium) approach, or a biomimetic approach. Each approach is described in its own separate section, with a thorough literature and state-of-the-art review.

Fiber Reinforced Polymer Composite as a Strengthening of Concrete Structures: A Review

For centuries, concrete is the main material most widely used in a building. The strength and durability of this material will decrease over time due to several factors that influence the mechanism of its structural characteristics. Although the compression strength is excellent, it is weak in tensile. Fiber reinforced polymer (FRP) composites are widely used as an alternative material to replace metal-based engineering materials. This material has properties such as lightweight products, low production costs, easy to form, high tensile and flexural strength, and elastic. The purpose of this review paper is to provide information about the application of FRP composites as reinforcement of concrete structures either as repairs or new structures. Initially, FRP composite materials were used as reinforcement structures for reinforced concrete column-beam joints. The resulting structure has increased the flexural ability due to the load given. The addition of natural fiber (jute) to concrete also increases in the hardness of concrete. Other investigations regarding the application of FRP composites in concrete to improve strength performance are discussed in this paper. Finally, the technique of wrapping FRP composites in concrete in an effort to improve the performance of the resulting structure is also discussed in the paper.

Preparation of high-performance transparent glass-fiber reinforced composites based on refractive index-tunable epoxy-functionalized siloxane hybrid matrix

Fiber reinforced polymer composites (FRPs) are widely utilized in various industrial fields due to their remarkable mechanical properties and low cost fabrication. However, typical FRPs cannot concurrently fulfill optical transparency and high mechanical strength, which are essential for transparent electronics and automotive applications. Here, we report a transparent FRP (GFRH) that exhibits high opto-mechanical properties by incorporating reinforced glass-fibers into refractive index-tunable epoxy-functionalized siloxane hybrid materials. To achieve transparent composites, we precisely control the refractive index of the siloxane matrix by adding an epoxy cross-linkable hardener. We compare the opto-mechanical properties of the GFRP according to various conditions in terms of curing method (thermal- and UV-curing), fiber content (from 0 to 25 wt% of matrix), fiber length (from 0.08 to 3 mm), and fiber type (filament mat, glass-fabric, chopped strands glass-fibers, and milled glass). Finally, to obtain high-performance GFRP, we further optimize the composite structure with short fiber (5 wt% of chopped strands glass-fibers) and long fiber (10 layers of glass-fabric). The optimized composite exhibits high optical transparency (80% @ 550 nm) and mechanical properties (251 MPa flexural strength, 9 GPa flexural modulus and 3 H pencil hardness). Our transparent composite has significant potential for the application of FRPs to transparent electronics and automotive devices.

Tribological behaviour of fibre-reinforced thermoset polymer composites: A review

Application of fibre-reinforced polymer composites has increased over the last two decades as compared to conventional materials. This improvement in the application of fibre-reinforced polymer composites is attributed to their unique material properties, such as high strength and stiffness-to-weight ratio, specific modulus and internal vibration damping. However, in most of the industrial applications, composite materials encounter tribological complications. Economic indicators and market dynamics suggested that the market for composite materials is booming and the dominant materials are carbon fibres, glass fibres and thermoset polymer (polyester resin) in resin segments. That is why tribological characteristics are crucial in designing carbon and glass-based fibre-reinforced polymer components. Owing to this importance, the study of tribological behaviour of fibre-reinforced polymer composite materials has expanded significantly. The present study has made an attempt to review the fundamental tribological applications and critical aspects of fibre-reinforced polymers, based on research work, which has been carried out over the past couple of decades. This work has primarily focused on the fibre-reinforced polymer composites, based on carbon and glass fibres with thermosets as the matrix material for probing into tribological behaviours. In the process, the focus has largely been on the most commonly occurring erosive and abrasive mode of wear process.

Tensile performance of additively manufactured short carbon fibre-PLA composites: neural networking and GA for prediction and optimisation

ABSTRACT Despite the vast applications of fibre-reinforced polymer composites in multiple domains, conventional fabrication is laden with many difficulties, thus bringing focus on Additive manufacturing technologies. The aim of this study is to evaluate the effect of infill percentage, layer thickness and carbon fibre layer position on the mechanical tensile performance of Fused Deposition Modelling (FDM) printed short Carbon Fibre-reinforced Polylactic Acid composites. Experimentation is based on full factorial design, with elastic modulus and maximum tensile stress as the response variables. Two distinct models for output are developed using an multivariate regression analysis and Generalised Regression Neural Network and are further validated through three set of randomised experiments. Genetic Algorithm is used to optimise the outputs, the results of which agree well with experiments. Changes in the carbon fibre layer position in the fabricated composites are found to have a visible and significant effect on the mechanical performance of the composites.

Impact of Application of Selected Composite Materials on the Weight and Vibroactivity of the Upper Gearbox Housing.

In this paper, exploratory studies on the application of fibre-reinforced polymer composites in the construction of gearbox housing elements that are used for transport means, as an alternative to traditionally used materials, were undertaken. Composite materials with three types of reinforcement were used: a glass-chopped strand mat, glass fabric, and carbon fabric. The manufactured elements were subjected to weight assessment and vibroactivity tests, including the recording of vibration and noise. The obtained results were compared to the values recorded for housings made of steel. It has been found that composite housings, while maintaining geometric similarity, are characterised by at least 60% lower weight compared to steel housings. It has been shown that in the frequency range below 1 kHz, composite housings are characterised by the presence of resonant frequencies with higher amplitudes than steel housings. At higher frequency ranges—above 1 kHz—composite housings had a lower vibroactivity level than steel housing. They allowed a significant reduction in the level of vibration and noise in this frequency range. The results obtained indicate that composite gearbox housings can be a good alternative to steel-based solutions.

Serotonin transporter gene hypermethylation – an epigenetic footprint of depressive symptomatology in panic disorder?

Recycling of composite materials, particularly renewable composites, in the offshore industry is a novel concept that is growing. It factors into the use of fiber-reinforced polymer (FRP) composites, their waste collection, and recycling process. Thus, the disposal and collection of these FRP composite wastes is also considered. The offshore industry has moved from shallow waters to deep waters and thus lighter structures are required, like composite risers. The focus is on the influence of the applicable renewable composite materials in the composite industry, the quality of the reinforced FRP composites, and the commercial flexibility. These include wind turbine blade recycling technologies. Since chemical processes produce good quality fibers, unlike mechanical processes that produce bad quality fibers, we will look at some applications of FRP composites in the offshore industry.

Temperature dependent bond strength model for GFRP laminate externally bonded to heat-damaged concrete

External bonding by the use of fiber-reinforced polymer (FRP) laminates to regain/improve the structural capacity of damaged/undamaged concrete members is a widely used popular method among various other retrofitting and strengthening techniques. A partial or full damage of concrete members due to accidental fire – that is at elevated temperature – often leads to significant reduction in the strength of concrete. The strength of such heat-damaged concrete structural members may be improved partly by the application of FRP composites – either by wrapping as whole or bonding locally on external surfaces. Both require understanding of the bond characteristics of FRP laminates with heat-damaged concretes. In this study, an improved temperature dependent bond strength (TDBS) model has been developed for predicting anchorage strength of glass fiber-reinforced polymer (GFRP) with heat-damaged concrete using the experimental results available from single-shear tests. The efficacy of proposed model in predicting the experimental values of interface bond strength of GFRP laminates with heat-damaged concrete has been critically shown by comparing the solutions from this study with other models reported in literature. A method for determining the debonding strain of FRP has also been discussed.

Polymers and composites made incredibly cheaply

Researchers have found a way to create industrially important thermoset polymer and fiber-reinforced polymer composite products at considerably lower expense than has been possible before. The approach could create products such as shaped composite panels for airplane fuselages using 10 orders of magnitude lower energy than current industrial manufacturing techniques. And the resulting polymers and composites have comparable properties—strength, thermal stability, bending resistance, and chemical resistance—to those made conventionally. The method could be useful for making a wide variety of polymer and composite products in a range of creative forms—including strong, lightweight shaped materials for the bodies of cars, boats, and planes, some of the largest-volume applications of fiber-reinforced polymer composites. Manufacturing high-performance thermoset components currently requires autoclaves that cure preshaped monomer resins by heating them under pressure. The size of the autoclave scales with the ...

Self-Reporting Fiber-Reinforced Composites That Mimic the Ability of Biological Materials to Sense and Report Damage.

Sensing of damage, deformation, and mechanical forces is of vital importance in many applications of fiber-reinforced polymer composites, as it allows the structural health and integrity of composite components to be monitored and microdamage to be detected before it leads to catastrophic material failure. Bioinspired and biomimetic approaches to self-sensing and self-reporting materials are reviewed. Examples include bruising coatings and bleeding composites based on dye-filled microcapsules, hollow fibers, and vascular networks. Force-induced changes in color, fluorescence, or luminescence are achieved by mechanochromic epoxy resins, or by mechanophores and force-responsive proteins located at the interface of glass/carbon fibers and polymers. Composites can also feel strain, stress, and damage through embedded optical and electrical sensors, such as fiber Bragg grating sensors, or by resistance measurements of dispersed carbon fibers and carbon nanotubes. Bioinspired composites with the ability to show autonomously if and where they have been damaged lead to a multitude of opportunities for aerospace, automotive, civil engineering, and wind-turbine applications. They range from safety features for the detection of barely visible impact damage, to the real-time monitoring of deformation of load-bearing components.

Durability of CFRP sheets and epoxy resin exposed to natural hygrothermal or cyclic wet‐dry environment

Fiber reinforced polymer (FRP) composites are used in harsh environments, resulting in degradation of their mechanical properties. Such degradation is critical in terms of the reliable design and application of FRP composites. In this study, a set of CFRP flat coupons and epoxy resin matrix flat coupons were prepared and subjected to alternating conditions of 10 h immersion in a 40°C NaCl solution with a concentration of 3.5%, and 14 h drying at 25°C and 60% relative humidity (RH). They were divided into five series, subjected to 0, 60, 120, 240, and 360 wet‐dry cycles, respectively. For a comparison with the acceleration simulation tests, the same numbers of specimens were exposed to a natural hygrothermal environment for 0, 6, 12, 18, and 30 months, respectively. After removal from the environment at the designated time, a series of tension tests were carried out. Based on the experimental results, the relationship regarding the tensile strength degradation of the CFRP sheets between the natural hygrothermal environment and the cyclic wet‐dry environment was determined. It was found that the tensile modulus of the CFRP sheets increased by 1.4%, and the tensile strength and ultimate strain decreased by 8.1% and 8.0% after 360 wet‐dry cycles, respectively. After a 30‐month natural exposure period, the tensile strength, tensile modulus, and ultimate strain of the CFRP sheets decreased by 9.9%, 3.4%, and 7.2%, respectively. The tensile property of the epoxy resin matrix appeared to be more sensitive to these two types of exposure environments than that of the CFRP sheets, and the tensile strength decreased by 59.4% at the end of 30‐month exposure. POLYM. COMPOS., 40:553–567, 2019. © 2017 Society of Plastics Engineers

Combined effects of sustained tensile loading and elevated temperatures on the mechanical properties of pultruded BFRP plates

Fiber reinforced polymer (FRP) composites have to face harsh environments and service loading conditions during practical use, causing their mechanical properties to degrade. Mitigating this degradation is critical for the safe design and application of FRP composites. In the present paper, the combined effects of sustained tensile loading and elevated temperatures on the mechanical properties of a pultruded basalt FRP (BFRP) plate were studied. The examined tensile stresses were set at 35%, 50% and 65% of its ultimate tensile strength (fu), and the exposure temperatures were room temperature, 80°C, 120°C and 160°C. Strain was recorded during testing, and variations of the tensile and interlaminar shear (ILSS) properties were studied. The tensile strain evolution of BFRP specimens during sustained tensile loading depended largely on the exposure temperature due to the temperature sensitivity of the epoxy resin. As the exposure temperature increased above the glass transition temperature (Tg) of the composites (123.7°C), a remarkable increase in strain was observed. Meanwhile, the residual tensile strength and tensile modulus decreased with the exposure temperature and sustained tensile loading level. The tensile strength and tensile modulus decreased by 41.8% and 30%, respectively, for the specimens exposed at 160°C and 50% fu. Sustained tensile loading led to stress redistribution in BFRP specimens especially at elevated temperatures, leading to serious degradation of the interlaminar shear strength (ILSS). Dynamic mechanical thermal analysis was performed to investigate the interface damage. An equation for predicting the tensile strength retention of BFRP plates under elevated temperatures was also proposed.

Structural Applications of Fiber-Reinforced Polymer (FRP) Composites in Australia and Philippines

Fiber-reinforced polymer (FRP) composites are considered viable alternatives due to their inherent advantages over traditional materials. Their advantages include light weight, high specific strength, high durability, corrosion resistance, chemical and environmental resistance, and low maintenance cost. This innovative material has been globally applied into civil infrastructure. In Australia, the applications include composite pile system and rehabilitation, marine structures, bridge structures and electrical cross-arms. On the other hand, strengthening of bridge and building structures are the common application of fiber composites in the Philippines. This paper presents the recent developments on the application of FRP composites in Australia and in the Philippines. Challenges in the implementation of this material are also presented. It is hoped that with the information revealed in this study, it will gain further application of this innovative material into civil infrastructure here in the Philippines.

Moisture diffusion in glass–fiber-reinforced polymer composite bridge under hot/wet environment

In literatures, researches on degradation of composites due to environmental effects were well documented on fiber-reinforced polymer (FRP) composites for Aerospace Engineering; for FRP composites utilized in Civil Engineering field, the available information was very limited. In order to keep pace with the application of FRP composites in Civil Engineering field, this research was undertaken to reveal more knowledge about the environmental degradation of FRP composite bridge under hot/wet environment. By gravimetric experiments, the moisture diffusion in thin-section of FRP composites and adhesives were characterized. Based on the analytical model of one-dimensional moisture diffusion theory, the diffusion coefficients were determined by the best least-square curve fitting to the experimental data. The finite element (FE) models of test specimens were developed and validated against experimental results. Through transient FE diffusion analysis, the moisture diffusion into the FRP-steel composite bridge deck system under a hot/wet environment was numerically predicted up to 100-year aging duration. The moisture uptake in adhesive connection was fully saturated after 26-year aging. The area between FRP composite sections and the adhesive layer was confirmed to be the most sensitive part to moisture effects. This research developed a step towards the prediction of long-term performance and life-time estimation of FRP-steel composite bridges.

Innovative Materials and Technologies for Construction and Restoration

new concepts and measures of safety. Tackling these issues requires integrated, multidisciplinary efforts between material- and structure-oriented experts. Even more complex is the problem of preservation and strengthening of historical buildings, which involves additional challenges such as reversibility, minimal intrusion and the expectation of durability over a century time scale. The aim of the conference was to provide an international forum for researchers, practitioners, and industry experts to exchange information and ideas on innovation in materials and technologies in the civil engineering field. The conference was conceived in three parts of focusing on: i Materials; ii Construction; and iii Restoration. The idea behind this format was to foster the interaction between experts working on civil engineering problems at different scales material, system and full structural, as well as with different perspectives structural engineers and restoration experts. The Special Issue contains fourteen papers from all three areas some being relevant to more than one area, all having passed the usual peer-review process before publication. Reflecting the trend of the papers presented at the conference, particular attention is devoted to the characterization and application of fiber-reinforced polymer composites for reinforcement or strengthening of structures.

Kings Stormwater Channel and I-5/Gilman Bridges, USA

Advanced composite materials, or fiber-reinforced polymer (FRP) composites, have found wide application in recent years in the rehabilitation of structures. Most of the primary structure applications of FRP composites have been as direct replacements for existing structural components, which may not be economically viable due to higher material costs. Therefore, the advantages of FRP, such as their weight, low life-cycle maintenance costs and mechanical tailorability, can only be effectively utilized when the structural systems offer reduced material usage and simplified construction procedures. The Kings Stormwater Channel and I-5/Gilman bridges represent the implementation of state-of-the-art knowledge on the use of FRP composites for civil infrastructure. The designs implement a variety of structural systems developed through several stages of research and development.