scholarly journals Aplicação da análise hierárquica como ferramenta de tomada de decisão para escolha do compósito de reforço com polímeros reforçados com fibras

2013 ◽  
Vol 3 (3) ◽  
pp. 161-176
Author(s):  
D. H. Perelles ◽  
M. F. Medeiros ◽  
M. R. Garcez
Keyword(s):  
Decision Making ◽  
Glass Fibers ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Analytic Hierarchy ◽  
Reinforced Polymers ◽  
Structural Reinforcement ◽  
De Se ◽  
Hierarchy Process ◽  
Decision Making Tool

RESUMOO reforço de estruturas com Polímeros Reforçados com Fibras (PRF) é uma alternativa que tem sido muito utilizada em intervenções executadas em elementos de concreto armado. A fibra de carbono é a mais empregada na formação dos compósitos de reforço utilizados em obras civis. Existe, no entanto, a possibilidade de se ampliar as opções de fibras formadoras do compósito utilizando as fibras de aramida e de vidro. Como uma ferramenta alternativa de tomada de decisão, o Método de Análise Hierárquica, baseado em critérios analisados de forma qualitativa e quantitativa, será utilizado neste trabalho para a avaliação das fibras de carbono, aramida e vidro, de forma a se obter qual material seria o mais apropriado para a execução de um reforço estrutural considerando como principais parâmetros de análise os custos dos materiais e as tensões e as deformações que os elementos poderão apresentar. A aplicação desta técnica de interpretação de resultados se mostrou muito útil, podendo ser considerada adequada para estudos que exijam uma tomada de decisão entre diferentes sistemas de reforço com PRF.Palabras clave: Reforço estrutural; polímeros reforçados com fibras; carbono; aramida; vidro; método da análise hierárquica.ABSTRACTStrengthening structures with Fiber Reinforced Polymers (FRP) is an alternative that has been used in interventions performed on reinforced concrete elements. Carbon fibers are the most used in the formation of composite reinforcement used in civil works. There is, however, possible to expand the options of forming fibers using the composite fibers of aramid and glass. As an alternative decision-making tool, the Analytic Hierarchy Process, based on criteria analyzed qualitatively and quantitatively, will be used in this work for the evaluation of carbon, aramid and glass fibers in order to obtain what material would be more suitable for the implementation of a structural reinforcement considering how key parameters of analysis material costs and the tensions and strains that may exhibit elements. This decision-making tool showed useful and can be considered suitable to select different FRP systems.Keywords: Structural strengthening; fiber-reinforced polymers; carbon; aramid; glass; hierarchical analysis method.

scholarly journals Additive Re-Manufacturing of Mechanically Recycled End-of-Life Glass Fiber-Reinforced Polymers for Value-Added Circular Design

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3545
Author(s):  
Alessia Romani ◽  
Andrea Mantelli ◽  
Raffaella Suriano ◽  
Marinella Levi ◽  
Stefano Turri
Keyword(s):  
Additive Manufacturing ◽  
Glass Fiber ◽  
End Of Life ◽  
Glass Fibers ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Glass Fiber Reinforced Polymers ◽  
Glass Fiber Reinforced ◽  
Circular Design

Despite the large use of composites for industrial applications, their end-of-life management is still an open issue for manufacturing, especially in the wind energy sector. Additive manufacturing technology has been emerging as a solution, enhancing circular economy models, and using recycled composites for glass fiber-reinforced polymers is spreading as a new additive manufacturing trend. Nevertheless, their mechanical properties are still not comparable to pristine materials. The purpose of this paper is to examine the additive re-manufacturing of end-of-life glass fiber composites with mechanical performances that are comparable to virgin glass fiber-reinforced materials. Through a systematic characterization of the recyclate, requirements of the filler for the liquid deposition modeling process were identified. Printability and material surface quality of different formulations were analyzed using a low-cost modified 3D printer. Two hypothetical design concepts were also manufactured to validate the field of application. Furthermore, an understanding of the mechanical behavior was accomplished by means of tensile tests, and the results were compared with a benchmark formulation with virgin glass fibers. Mechanically recycled glass fibers show the capability to substitute pristine fillers, unlocking their use for new fields of application.

scholarly journals A Study of the Dry Linear Contact Between Glass Fiber-reinforced Composite Materials and Steel

2019 ◽  
Vol 56 (3) ◽  
pp. 616-620
Author(s):  
Virgil Florescu ◽  
Dorin Rus ◽  
Laurentiu Rece
Keyword(s):  
Glass Fiber ◽  
Glass Fibers ◽  
Fiber Reinforced Polymers ◽  
Wear Behaviour ◽  
Wear Volume ◽  
Wear Depth ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Wear Process ◽  
Glass Fiber Reinforced

The thermoplastic materials studied are biphasic. They consist of a polymer mass and a short glass fiber, the percentage being between 10 and 30%. We have shown, both analytically and graphically, the evolution of wear occurring on the steel surface in contact with glass fiber-reinforced polymers. The evolution in time of this process depends on the evolution of the friction coefficient in the process of the dry linear contact between different polymers and different types of steels. We have made a connection between the theoretical case and the experimental results. The experimental method used was the wear imprint method through which the wear depth and wear volume were determined. The wear process is complex and is accompanied by adhesion and corrosion phenomena. Any modification of the input parameters such as speed, temperature, load, quantity of glass fibers in the polymer lead at a certain one evolution of the wear behaviour of the composite material.

Developing an analytic hierarchy process-based decision model for modular construction in urban areas

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Michael Sing ◽  
Joseph Chan ◽  
Henry Liu ◽  
Nancy Hei Ngai
Keyword(s):  
Decision Making ◽  
Urban Area ◽  
Urban Areas ◽  
Modular Construction ◽  
Analytic Hierarchy ◽  
Content Type ◽  
Decision Making Factors ◽  
Decision Making Model ◽  
Hierarchy Process ◽  
Decision Making Tool

Purpose Modular construction is considered a well-established construction method for improving the efficiency of the construction industry worldwide. However, the industry struggles to achieve higher levels of modularisation in urban areas. Previous studies on decision-making for modularisation have, so far, not focussed much on its application in urban areas. As modular construction could bring lots of advantages such as speed of construction, This study aims to develop a decision-making tool that can assist the project planners in deciding whether the modular construction techniques should be applied in their urban area project. Design/methodology/approach Based on the literature review, a total of 35 decision-making factors of modularisation were identified for this study. The decision-making model is then developed to evaluate the significance of each factor using the analytic hierarchy process (AHP) approach. A total number of 72 valid responses were obtained and analysed. The geometric mean of priorities is adopted to obtain the par-wise comparison between the critical factors in which each factor’s weighting in the decision-making model is calculated. Afterwards, the robustness of the decision-making model is demonstrated by the real-life projects in China, Hong Kong and the UK, respectively. Findings A total of 35 decision-making factors allocated in five criteria for modular construction selection in urban areas were identified. The criteria include site attributes, project characteristics, labour consideration, environmental and organisation and project risk. Their impact was calculated using the AHP to indicate the relative importance with respect to the adoption of modularisation in urban areas. Afterwards, a two-level decision-making model was developed that can be used as a decision-making tool for the adoption of modular construction. Practical implications The outcome of this research will be beneficial to industrial practitioners and academics in understanding the critical attributes that affect the adoption of modular construction in an urban area. It further enables the building professionals to assess the feasibility of using modular construction in their projects, especially at the early stage, so as to facilitate its use. Originality/value There is a number of literature on the decision-making model on the adoption of modular construction. However, previous studies did not provide specific concerns related to urban areas, whereas there is an urgent need to have an updated analysis that can be catered to the modular construction in the urban area. In this research study, the 35 decision-making factors were ranked by the experienced project managers and then a pair-wise comparison was conducted. With this information, the robust decision-making model is formulated to offer a kept promised indicator in adopting modularisation in the urban area.

Shear Performance of Reinforced Concrete Beams with GFRP

2020 ◽  
Vol 1002 ◽  
pp. 531-540
Author(s):  
Suaad K. Ibraheem Al-Fadhli
Keyword(s):  
Load Capacity ◽  
Glass Fibers ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Glass Fiber Reinforced ◽  
Shear Performance ◽  
Practical Program

"Fiber Reinforced Polymers FRP" provide good alternatives to regular reinforcing steel, as their resistance to environmental factors specifies them and provide durability, in addition to their appropriate prices. These polymers are of various compositions and forms, some of which have a basic composition of glass fibers, others contain carbon or additional materials. They have used instead of steel reinforcement as the main longitudinal rebar, also as laminates that can be attached to the concrete surfaces for shear or flexural resistance. In this study, "Glass Fiber Reinforced Polymers GFRP" has tested for shear performance, where a practical program has applied. Three "simply supported beams" as control specimens have been prepared and tested, with the other nine beams with different combinations of reinforcement of steel and GFRP for flexure and shear resistance. Specimens have examined and the results have analyzed. The results showed that the use of GFRP as for main reinforcement with GFRP laminates instead of shear steel reinforcement increases the load capacity by 11%, also decreases the deflection by 46%.

scholarly journals Ageing and Fatigue Combined Effects on GFRP Grids

2017 ◽  
Vol 747 ◽  
pp. 525-532 ◽  
Author(s):  
Lara Calabrese ◽  
Francesco Micelli ◽  
Marco Corradi ◽  
Maria Antonietta Aiello ◽  
Antonio Borri
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Tensile Strength ◽  
Glass Fibers ◽  
Fatigue Loading ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Glass Fiber Reinforced ◽  
Before And After

Many areas of Europe, especially Italy, Greece, Slovenia and other Balkan States, are generally associated with earthquakes. In the last two decades Fiber Reinforced Polymers (FRP) have gained an increasing interest, mostly for upgrading, retrofitting and repair of masonry and timber structures belonging to the architectural heritage. Recent researches demonstrated that masonry constructions or single structural elements are likely to be effectively repaired or enhanced in their mechanical properties using FRPs. The objective of the research presented in this paper is to study the long-term behavior of composite grids, made of E-CR glass fibers and epoxy-vinylester resin, subjected to harsh environmental factors including fatigue loading and ageing in aqueous solution. The paper presents new original test results on the relationship between the durability and the governing material properties of GFRP (Glass Fiber Reinforced Polymers) grids in terms of tensile strength and axial strains, using specimens cut off from GFRP grids before and after ageing in aqueous solution. The tensile strength of a GFRP grid was measured after conditioning in alkaline bath made by deionized water and Ca(OH)2, 0.16% in weight, solution. The reduction in terms of tensile strength and Young’s modulus of elasticity compared to unconditioned specimens is illustrated and discussed. This degradation indicated that extended service in alkaline environment under fatigue loads may produce reductions in the GFRP mechanical properties which should be considered in design, where cyclic loads and aggressive conditions are prevented in service life.

scholarly journals On-Demand Photopolymerization of Fiber-Reinforced Polymers Exhibiting the Shape Memory Effect

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4300
Author(s):  
Xavier Allonas ◽  
Johann Pierrel ◽  
Ahmad Ibrahim ◽  
Céline Croutxé-Barghorn
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Glass Fibers ◽  
Polymer Chains ◽  
Fiber Reinforced Polymers ◽  
Secondary Amines ◽  
Fiber Reinforced ◽  
One Pot ◽  
Reinforced Polymers

Fiber-reinforced polymers exhibiting the shape memory effect were created on the basis of a one-pot three-step chemical process. The first step is a Michael addition, which creates linear polymer chains. The second step is free radical photopolymerization, which increases the degree of curing of polymers. The last step is post-consolidation due to the reaction of previously formed secondary amines on the residual double bonds. By employing such chemistry to impregnate glass fibers, the final composite exhibits a convincing shape memory effect, as shown by cyclic thermomechanical tests.

scholarly journals Application of AHP Method to Aid Destination Choice of Pre-Production Models in a Textile Industry

2019 ◽  
Vol 7 (10) ◽  
pp. 106-112
Author(s):  
Karine Ramos ◽  
Vilson Menegon Bristot ◽  
David Batista Gesuíno ◽  
Márcio Carlos Just ◽  
Bruno Brogni Uggioni ◽  
...  
Keyword(s):  
Decision Making ◽  
Analytic Hierarchy Process ◽  
Textile Industry ◽  
Destination Choice ◽  
Ahp Method ◽  
Analytic Hierarchy ◽  
Production Models ◽  
Hierarchy Process ◽  
Disposal Problem ◽  
Decision Making Tool

The study analyzed, through the Analytic Hierarchy Process (AHP) technique, the decision-making tool, the best resolution for the final disposal problem of pre-pruduction models of a garment company. Obtaining data was based on the identification of the problem, general understanding of how to improve and finally the application of the AHP method, it was concluded that the best decision was archiving the pieces, guaranteeing fidelity in the reproduction of the product and the aid for the development of new parts.

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