Shape Design Enhancement of Pultruded FRP Profiles for Structures Ancillary to Masonry Constructions

2019 ◽  
Vol 817 ◽  
pp. 83-88
Author(s):  
Giosuè Boscato ◽  
Ivano Aldreghetti ◽  
Daniele Baraldi ◽  
Antonella Cecchi ◽  
Giorgio Costantini ◽  
...  
Keyword(s):  
Cross Sections ◽  
Ad Hoc ◽  
Shear Stiffness ◽  
Numerical Approach ◽  
Fiber Reinforced Polymers ◽  
Structural Systems ◽  
Historical Building ◽  
Structural Improvement ◽  
Structural Reinforcement ◽  
Steel Shapes

The historical building heritage, monumental, civil and industrial has highlighted, especially in the last decade, the high vulnerability with respect to horizontal actions. The need to design stable and strong structural systems with respect to the stresses acting in various directions has oriented research to develop lightweight technologies for structural systems, independent or ancillary, with reduced mass to mitigate the consequent applied load. In this scenario all-FRP (Fiber Reinforced Polymers) systems can be a valid alternative for new constructions and / or structural reinforcement. The scenario described above, highlights the importance of developing innovative technologies suitable for the functional and structural improvement of the existing buildings. It is necessary to define an innovative approach aimed at identifying an ad-hoc profile for the FRP pultruded profiles (currently referring to the steel shapes), which allows to capitalize the performance capabilities, limiting the main defects related to low shear stiffness of FRP pultruded material. This research analyses how the shape enhancement of the cross sections, with shape redraw, allows to increase the structural performances of FRP pultruded profiles. Experimental data of previous research on buckling behaviour of different open cross section profiles, narrow and wide flanges, have been analysed and validated by numerical approach and compared with new strengthened shapes.

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.

3D Analysis of Bridges Changing Structural Systems – An Easy Design Tool

2015 ◽  
Vol 796 ◽  
pp. 69-75
Author(s):  
Vladimír Křístek ◽  
Lukáš Kadlec
Keyword(s):  
Cross Sections ◽  
Design Tool ◽  
Structural Systems ◽  
Concrete Bridge ◽  
3D Analysis ◽  
Box Girders ◽  
Reliable Determination ◽  
The Real ◽  
Bridge Structures ◽  
Primary Advantage

Due to increase of requirements on accuracy of structural analyses, practically applicable computational tools for reliable determination of the real structural performance of bridges are needed. A method is proposed for the true full 3D analysis which can be applied to achieve the real spatial behaviour of concrete bridge structures taking into account rheological phenomena and changes of structural systems. Particularly, the effects of shear lag, shear performance of webs of box girders, warping torsion, warping of cross-sections, distortional effects, state of stresses in the singular regions, the real prestress loss, etc., can be correctly determined. The method combines conventional approaches (based on the elementary beamtype assumptions) for calculating the time development of the internal forces due to rheological phenomena and changes in the structural system during construction and routine commercial FEM software intended for calculating spatial shell structures. The method is capable to give the true 3D prediction of structure behaviour by using only commercially available software. The primary advantage of the proposed method is its ease of application which allows the true 3D performance to be determined from simple calculations. The method offers the designers of concrete bridge girders an ideal design tool. The correct 3D simulation can lead to more efficient and economical designs.

scholarly journals Thermomechanical Characterization of CFRPs under Elevated Temperatures for Strengthening Existing Structures

Fibers ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 80
Author(s):  
Christina Papadimitriou ◽  
Lazaros Melidis ◽  
Lambros Kotoulas ◽  
Nikolaos Makris ◽  
Konstantinos Katakalos
Keyword(s):  
Thermal Loading ◽  
Elevated Temperatures ◽  
Tensile Load ◽  
Concrete Columns ◽  
Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Existing Structures ◽  
Structural Reinforcement ◽  
Constant Tensile Load

Fiber-reinforced polymers (FRP) are rapidly gaining acceptance from the construction sector due to their large effectiveness. They are mainly used as confining reinforcement for concrete columns and as tensile reinforcement for concrete beams, columns and slabs. FRPs are already used to a large extent for applications such as bridges and parking lots, where elevated temperatures are not the main risk. Their increasing use as structural reinforcement is hampered by the concern related to their behavior at elevated temperatures as the relevant research is deficient. Thanks to the significant advantage of FRPs’ mechanical properties, further investigation into the influence of heating on their mechanical behavior may solve many doubts. The present study examines the influence of temperatures, ranging among 50, 100 and 250 °C, on the tensile strength of FRP laminates with carbon fibers (CFRP). In addition, the resistance of CFRP specimens to low-cycle thermal loading at the temperatures of 50, 100 and 250 °C under constant tensile load was investigated. The experiments were carried out in the laboratory of Experimental Strength of Materials and Structures of Aristotle University of Thessaloniki.

Characterization of N-Vinyl pyrrolidone grafting into silicone rubber

1989 ◽  
Vol 47 ◽  
pp. 882-883
Author(s):  
R. Lee ◽  
R. Greer
Keyword(s):  
Cross Sections ◽  
Silicone Rubber ◽  
Sodium Bicarbonate Solution ◽  
Monomer Concentration ◽  
Surface Preparation ◽  
Vinyl Pyrrolidone ◽  
Grafted Polymers ◽  
Depth Of Penetration ◽  
Structural Reinforcement ◽  
Thickness Measurements

Since 1960, hydrogels have been utilized in a large number of biomedical products. The poor mechanical strength of hydrogels necessitates the use of a stronger support material in order to provide structural reinforcement. Methods of surface preparation include radiation grafting. Parameters of importance for grafting N-vinyl pyrrolidone (NVP) into silicone rubber include the choice of solvent, monomer concentration, radiation dose and use of selective inhibitors. Post irradiation extraction of homopolymer and monomer from the silicone rubber substrate after grafting is an important step. NVP grafted polymers can be stained by many dyes for depth of penetration studies.Fourteen cm sections of non-reinforced Silastic® (silicone rubber, Dow Corning) tubing, 0.078″x0.125″, were boiled for three 1 h periods in aqueous 2.0% sodium bicarbonate solution. Prior to irradiation, monomer solutions used to fill tubes were bubbled with nitrogen for at least 30 min. Several monomer/solvent formulations (100% NVP; 80% NVP/20% methanol; and 60% NVP/40% methanol, and gamma irradiation doses (50, 150, 200 and 250 krad) were used.) After irradiation, samples were flushed with either acetone/methanol (50:50 v/o) or ethanol/water (50:50 v/o) , followed by three 30 min agitated washes in the same type of solution. To test the effect of methanol concentration on rim thickness measurements, 0.5 cm lengths of cleaned Silastic , acetone/methanol extracted Silastic®, and grafted tubing of 100% NVP and 80% NVP/20% methanol formulations were immersed in 0.1% acid fuchsin stains in 10, 50, and 100% methanol for 48 h. After rinsing and drying, cross sections were cut, and the penetration depth of the stain (i.e., graft depth) was measured.

On the Bow-Shock dynamics in response to a Quasi-Perpendicular interaction with different Solar Wind conditions

2021 ◽  
Author(s):  
Emanuele Cazzola ◽  
Dominique Fontaine ◽  
Philippe Savoini
Keyword(s):  
Solar Wind ◽  
Computer Simulations ◽  
Cross Sections ◽  
Ad Hoc ◽  
Three Dimensional ◽  
Bow Shock ◽  
Hybrid Code ◽  
Mach Numbers ◽  
The Imf

<p>This work will be giving new insights into the global Quasi-Perpendicular interaction effects of the Solar Wind with a realistic three-dimensional terrestrial-like curved Bow Shock (BS) by means of hybrid computer simulations.<br>The Bow-Shock profoundly changes its behavior for different incoming Solar Wind conditions. For Alfvénic Mach numbers greater than a specific threshold, the Bow-Shock shows an intense rippling phenomenon propagating along its surface, as well as the formation of a set of waves in the near-Earth flanks.<br>A similar rippling has been observed from different independent in-situ satellite crossings, as well as studied with ad-hoc computer simulations configured with 2D-planar shocks, conclusively confirming the highly kinetic nature of this phenomenon. Yet, the possible effects of a global three-dimensional curved interaction are still poorly described.<br>As such, we have performed a series of 3D simulations at different Alfvénic Mach numbers, different plasma beta - ratio between the thermal to the magnetic pressures - and different incoming Interplanetary Magnetic Field (IMF) configurations with the hybrid code LatHyS, which was already successfully used for similar past analyses.<br>Particularly, we have found that the ripples follow a pattern not directly driven by the IMF direction as initially expected, but rather a Nose-to-Flanks propagation with the rippling onset region  being significantly displaced from the nose position. Additionally, this phenomenon seems to be mainly confined to the plane on where the IMF direction lies, with the perpendicular cross-sections showing only a slight oscillation.<br>Finally, we have observes a significant ions acceleration in the local perpendicular directions along the flanks modulations, which is most likely related to the local IMF-BS normal fluctuations occurring in the ripples boundary.</p>

Towards a Numerical Approach of Finding Candidates for Additive Manufacturing-Enabled Part Consolidation

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Sheng Yang ◽  
Florian Santoro ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Additive Manufacturing ◽  
Ad Hoc ◽  
Numerical Approach ◽  
Design Guidelines ◽  
Design Stage ◽  
Physical Interaction ◽  
Physical Attributes ◽  
Conflict Handling ◽  
Part Consolidation ◽  
Typical Design

Part consolidation (PC) is one of the typical design freedoms enabled by additive manufacturing (AM) processes. However, how to select potential candidates for PC is rarely discussed. This deficiency has hindered AM from wider applications in industry. Currently available design guidelines are based on obsolete heuristic rules provided for conventional manufacturing processes. This paper first revises these rules to take account of AM constraints and lifecycle factors so that efforts can be saved and used at the downstream detailed design stage. To automate the implementation of these revised rules, a numerical approach named PC candidate detection (PCCD) framework is proposed. This framework is comprised of two steps: construct functional and physical interaction (FPI) network and PCCD algorithm. FPI network is to abstractly represent the interaction relations between components as a graph whose nodes and edges have defined physical attributes. These attributes are taken as inputs for the PCCD algorithm to verify conformance to the revised rules. In this PCCD algorithm, verification sequence of rules, conflict handling, and the optimum grouping approach with the minimum part count are studied. Compared to manual ad hoc design practices, the proposed PCCD method shows promise in repeatability, retrievability, and efficiency. Two case studies of a throttle pedal and a tripod are presented to show the application and effectiveness of the proposed methods.

Image-velocimetry techniques under particle aggregation for streamflow monitoring: a numerical approach

2020 ◽  
Author(s):  
Alonso Pizarro ◽  
Silvano Fortunato Dal Sasso ◽  
Salvatore Manfreda
Keyword(s):  
Large Scale ◽  
Ad Hoc ◽  
Numerical Approach ◽  
Surface Flow ◽  
Particle Aggregation ◽  
Seeding Density ◽  
Stream Flows ◽  
Flow Monitoring ◽  
Time Flow ◽  
Image Velocimetry

<p>Monitoring extreme events with high accuracy and consistency is still a challenge, even by using up-to-date approaches. On the one side, field campaigns are in general expensive and time-consuming, requiring the presence of high-qualified personnel and forward planning. On the other side, non-contact approaches (such as image velocimetry, radars, and microwave systems) have had promising signs of progress in recent years, making now possible real-time flow monitoring. This work focuses on the estimation of surface flow velocities for streamflow monitoring under particle aggregation, in which tracers are not necessarily uniformly distributed across the entire field of view. This issue is extremely relevant for the computing stream flows since velocity errors are transmitted to river discharge estimations. Ad-hoc numerical simulations were performed to consider different levels of particle aggregation, particle colour and shapes, seeding density, and background noise. Particle Tracking Velocimetry (PTV) and Large-Scale Particle Image Velocimetry (LSPIV) were used for image velocimetry estimations due to their widely used worldwide. Comparisons between the theoretical and computed velocities were carried out to determine the associated uncertainty and optimal experimental setup that minimises those errors.</p>

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