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Article
Publication date: 3 February 2020

Feras Korkees, James Allenby and Peter Dorrington

3D printing of composites has a high degree of design freedom, which allows for the manufacture of complex shapes that cannot be achieved with conventional manufacturing…

Abstract

Purpose

3D printing of composites has a high degree of design freedom, which allows for the manufacture of complex shapes that cannot be achieved with conventional manufacturing processes. This paper aims to assess the design variables that might affect the mechanical properties of 3D-printed fibre-reinforced composites.

Design/methodology/approach

Markforged Mark-Two printers were used to manufacture samples using nylon 6 and carbon fibres. The effect of fibre volume fraction, fibre layer location and fibre orientation has been studied using three-point flexural testing.

Findings

The flexural strength and stiffness of the 3D-printed composites increased with increasing the fibre volume fraction. The flexural properties were altered by the position of the fibre layers. The highest strength and stiffness were observed with the reinforcement evenly distributed about the neutral axis of the sample. Moreover, unidirectional fibres provided the best flexural performance compared to the other orientations. 3D printed composites also showed various failure modes under bending loads.

Originality/value

Despite multiple studies available on 3D-printed composites, there does not seem to be a clear understanding and consensus on how the location of the fibre layers can affect the mechanical properties and printing versatility. Therefore, this study covered this design parameter and evaluated different locations in terms of mechanical properties and printing characteristics. This is to draw final conclusions on how 3D printing may be used to manufacture cost-effective, high-quality parts with excellent mechanical performance.

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Article
Publication date: 17 May 2021

Jesús Miguel Chacón, Miguel Ángel Caminero, Pedro José Núñez, Eustaquio García-Plaza and Jean Paul Bécar

Fused filament fabrication (FFF) is one of the most popular additive manufacturing (AM) technologies due to its ability to build thermoplastic parts with complex…

Abstract

Purpose

Fused filament fabrication (FFF) is one of the most popular additive manufacturing (AM) technologies due to its ability to build thermoplastic parts with complex geometries at low cost. The FFF technique has been mainly used for rapid prototyping owing to the poor mechanical and geometrical properties of pure thermoplastic parts. However, both the development of new fibre-reinforced filaments with improved mechanical properties, and more accurate composite 3D printers have broadened the scope of FFF applications to functional components. FFF is a complex process with a large number of parameters influencing product quality and mechanical properties, and the effects of the combined parameters are usually difficult to evaluate. An array of parameter combinations has been analysed for improving the mechanical performance of thermoplastic parts such as layer thickness, build orientation, raster angle, raster width, air gap, infill density and pattern, fibre volume fraction, fibre layer location, fibre orientation and feed rate. This study aims to assess the effects of nozzle diameter on the mechanical performance and the geometric properties of 3D printed short carbon fibre-reinforced composites processed by the FFF technique.

Design methodology approach

Tensile and three-point bending tests were performed to characterise the mechanical response of the 3D printed composite samples. The dimensional accuracy, the flatness error and surface roughness of the printed specimens were also evaluated. Moreover, manufacturing costs, which are related to printing time, were evaluated. Finally, scanning electron microscopy images of the printed samples were analysed to estimate the porosity as a function of the nozzle diameter and to justify the effect of nozzle diameter on dimensional accuracy and surface roughness.

Findings

The effect of nozzle diameter on the mechanical and geometric quality of 3D printed composite samples was significant. In addition, large nozzle diameters tended to increase mechanical performance and enhance surface roughness, with a reduction in manufacturing costs. In contrast, 3D printed composite samples with small nozzle diameter exhibited higher geometric accuracy. However, the effect of nozzle diameter on the flatness error and surface roughness was of slight significance. Finally, some print guidelines are included.

Originality value

The effect of nozzle diameter, which is directly related to product quality and manufacturing costs, has not been extensively studied. The presented study provides more information regarding the dependence of the mechanical, microstructural and geometric properties of short carbon fibre-reinforced nylon composite components on nozzle diameter.

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Article
Publication date: 2 March 2015

Wei Huang, Sima Didari, Yan Wang and Tequila A.L. Harris

Fibrous porous media have a wide variety of applications in insulation, filtration, acoustics, sensing, and actuation. To design such materials, computational modeling…

Abstract

Purpose

Fibrous porous media have a wide variety of applications in insulation, filtration, acoustics, sensing, and actuation. To design such materials, computational modeling methods are needed to engineer the properties systematically. There is a lack of efficient approaches to build and modify those complex structures in computers. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, the authors generalize a previously developed periodic surface (PS) model so that the detailed shapes of fibers in porous media can be modeled. Because of its periodic and implicit nature, the generalized PS model is able to efficiently construct the three-dimensional representative volume element (RVE) of randomly distributed fibers. A physics-based empirical force field method is also developed to model the fiber bending and deformation.

Findings

Integrated with computational fluid dynamics (CFD) analysis tools, the proposed approach enables simulation-based design of fibrous porous media.

Research limitations/implications

In the future, the authors will investigate robust approaches to export meshes of PS models directly to CFD simulation tools and develop geometric modeling methods for composite materials that include both fibers and resin.

Originality/value

The proposed geometric modeling method with implicit surfaces to represent fibers is unique in its capability of modeling bent and deformed fibers in a RVE and supporting design parameter-based modification for global configuration change for the purpose of macroscopic transport property analysis.

Details

Engineering Computations, vol. 32 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 7 September 2015

Milesa Ž Sreckovic, Branka Kaludjerovic, Aleksander G Kovacevic, Aleksandar Bugarinovic and Dragan Družijanic

The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory…

Abstract

Purpose

The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory conditions to beams of various laser types.

Design/methodology/approach

Carbon fabric materials – fiber, felt and cloth – obtained from different precursor materials and prepared at various process conditions (oxidized, partially carbonized, carbonized, graphitized), were exposed to pulses of various lasers (Nd3+: YAG, alexandrite, ruby).

Findings

Depending on the laser power, plasma and destructive phenomena occurred. In the case of an interaction between a Nd3+: YAG laser beam and specimens of thickness in millimeter range, the authors have estimated the threshold of the energy density for drilling and discussed the possible models of the interaction.

Research limitations/implications

The results have implications in the estimations of quality as well as in the improvement of material processing, giving some new light to the changes of mechanical and optical constants of the material, as well as to the changes of carbon groups of the material, which would be useful for different types of modeling. Future research will be in the interaction of laser beams with various textile materials, where the investigation would cover the microstructure changes and the implications on cloth cutting and welding, concerning the damages as well as relief structures, specially renew for fs laser regimes.

Originality/value

The area of laser applications in the textile industry is supported by scientific and applicative exploration. However, fewer results are concerned with deep introspection into the microstructure of the damages considering the laser interaction with carbon fiber and other carbon-based textiles.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 3 May 2016

Julián Sierra-Pérez and Alfredo Güemes

The purpose of this paper is to study techniques of pattern recognition in the strain field as structural health monitoring tools. The changes in the strain field may be…

Abstract

Purpose

The purpose of this paper is to study techniques of pattern recognition in the strain field as structural health monitoring tools. The changes in the strain field may be very intense at the tip of a crack but smooth out very quickly. So trying to get information about damage occurrence from strain measurements is a difficult task, as the detected strain changes may be very small and masked by temperature drifting, load changes or any other environmental factor.

Design/methodology/approach

It drives to the need to include a large sensor array into the structure, which is not difficult when using optical fiber sensors. Experiments were done on a simple cantilever beam, instrumented with 32 sensors and submitted to loads and progressive damage conditions. The same approach was applied to a more complex structure, the wing of an unmanned air vehicle (UAV) made in composite materials.

Findings

Algorithms based on principal component analysis (PCA), damage indices and damage thresholds were used and shown to be simple and robust enough for this task.

Originality/value

The data treatment was done in a fully automated approach; an algorithm to compare and extract information from the multiple strain measurements was developed for this task.

Details

Aircraft Engineering and Aerospace Technology: An International Journal, vol. 88 no. 3
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 1 January 1987

Roger Main

Roger Main gives a four‐part report on the optical technologies which are playing an increasingly important role in sensor development.

Abstract

Roger Main gives a four‐part report on the optical technologies which are playing an increasingly important role in sensor development.

Details

Sensor Review, vol. 7 no. 1
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 February 1992

Gordon Oscroft

Numerous articles have been written about the many applications for fibre optic sensors and their future potential. However, very few products are yet in volume production.

Abstract

Numerous articles have been written about the many applications for fibre optic sensors and their future potential. However, very few products are yet in volume production.

Details

Sensor Review, vol. 12 no. 2
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 7 August 2007

Richard Bloss

This paper sets out to report on the developments in the evolution of advanced composite fibre structure production systems, to highlight advanced equipment already in…

Abstract

Purpose

This paper sets out to report on the developments in the evolution of advanced composite fibre structure production systems, to highlight advanced equipment already in production and to examine efforts to extend automated technology to assessing damage and automatically repairing composite fibre structures.

Design/methodology/approach

Leading companies in design and construction of advanced composite fibre production machinery are teaming with other technology leaders to further automate the inspection, damage assessment and repair of composite fibre structures. Automated control and movement of inspection scanners, coupled with computer analysis of findings, provide input to repair program generation. The repair program then can direct the ultrasonic cutting and composite fibre tape‐laying procedures necessary to complete the repair. Also important is the coordination of a material‐handling system to link the parts and the required production subsystems.

Findings

The outlook for totally automated repair looks very promising. Success appears to depend more on implementation and automation of known technologies and less on the development of totally new technology. Key are the software developments necessary to complete the system integration.

Practical implications

A team approach, where leaders in their own technology join together rather than an expert in one area attempting to become an expert in other technologies, looks like a more productive answer. A bonus is that the end result will be the combination of the best of all the applicable technologies.

Originality/value

Seeing the results of others in tackling what may seem like a hard to automate application by employing a team of vendors can provide a road‐map to success in addressing other requirements.

Details

Assembly Automation, vol. 27 no. 3
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 1 July 2004

A.E. Richardson

This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but…

Abstract

This paper makes a comparison between the electrical properties of cement grout with and without monofilament polypropylene fibre additions. The findings show a small, but significant difference between the electrolytic transport properties of cement grout with monofilament polypropylene fibre additions when compared to grout without fibre additions. The grout with fibre additions suggests a reduced probability of water and ion transmission, due to higher measured resistivity, which will result in enhanced durability and lower life cycle costs. Durability of reinforced concrete structures, is known to be closely linked to the water permeability of the concrete matrix. This potential trend for enhanced durability can be added to the other benefits of using monofilament polypropylene fibre in concrete, such as low absorption, freeze/thaw resistance, fire resistance and micro reinforcement.

Details

Structural Survey, vol. 22 no. 3
Type: Research Article
ISSN: 0263-080X

Keywords

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Article
Publication date: 1 February 1992

Radislav Potyrailo and Sergei Golubkov

Achievements in guided wave optics have had a great influence on many areas of technology for several years. Fibre optic communication links, sensors for various…

Abstract

Achievements in guided wave optics have had a great influence on many areas of technology for several years. Fibre optic communication links, sensors for various parameters, recently developed distributed temperature sensors, integrated optical switches, etc. are all applications that are commercially available. The field of analytical chemistry is no exception in this growing technology. In order to compete with well‐established chemical‐sensing instrumentation, optical waveguide chemical sensors (OWCSs) must show all the qualities of such instrumentation. OWCSs combine well‐known features of sensors, based on waveguide optics, with optical methods of chemical analysis and offer advantages over other types of chemical sensor. OWCSs are electrically passive, corrosion‐resistant, can respond to analytes for which other chemical sensors are not available, and referencing can be carried out optically. They allow multicomponent measurements at several wavelengths, have a common technology for fabrication of sensors for different chemical and physical parameters and are easily compatible with telemetry etc. Further, only OWCSs are capable of distributed sensing. However, interference from ambient light, temperature, long‐term instability, relatively slow response time, and limited dynamic range may be a problem for some types of OWCS. These disadvantages can be considerably reduced using various methods.

Details

Sensor Review, vol. 12 no. 2
Type: Research Article
ISSN: 0260-2288

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