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1 – 10 of 697B. Namiranian, S. Shaikhzadeh Najar and A. Salehzadeh Nobari
The purpose of this paper is to evaluate some important parameters in plate buckling of fused interlining worsted fabric with different weight and laying‐up direction. The article…
Abstract
Purpose
The purpose of this paper is to evaluate some important parameters in plate buckling of fused interlining worsted fabric with different weight and laying‐up direction. The article compares the formability of fused fabric composite by two different methods (Lindberg's hypothesis and fabric assurance by simple testing method).
Design/methodology/approach
Plate buckling compression behavior of fused fabric composite is investigated using a special designed clamp according to Dahlberg's test method.
Findings
The result shows that fusible interlining lay‐up angle significantly influences on buckling parameters. It is indicated that the buckling behavior of fused fabric composite against lay‐up interlining direction is in accordance with interlining buckling behavior. The result of research suggests that the formability behavior of fused fabric composite with interlining lay‐up direction is predictable according to Lindberg's method.
Research limitations/implications
Experimental design is limited at low speed. Further research works are needed to perform buckling behavior of fused fabric composites at higher speeds as well as under cyclic loading conditions.
Originality/value
Compression plate buckling behavior of fused interlining fabrics is predictable against interlining laying‐up direction. The result of this research could be used in the area of garment quality serviceability.
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Lorenzo Malagutti, Valentina Mazzanti and Francesco Mollica
The architecture of 3D-printed parts made through fused deposition modelling (FDM) with raster infill resembles that of composite laminates. Classical lamination theory (CLT), the…
Abstract
Purpose
The architecture of 3D-printed parts made through fused deposition modelling (FDM) with raster infill resembles that of composite laminates. Classical lamination theory (CLT), the simplest model for composite laminates, has been proved successful for describing the stiffness properties of FDM parts, while strength modeling so far has been limited to unidirectional lay-ups. The aim of this paper is to show that CLT can be used to predict also FDM part failure.
Design/methodology/approach
Wood flour-filled polyester has been chosen as a model material. Unidirectional specimens oriented at 0°, 90° and ± 45° have been first characterized in simple tension to obtain the properties of the single layer. Next, two quasi-isotropic lay-ups, possessing different layer sequences, have been tested again in simple tension for CLT validation.
Findings
The measured properties are in good agreement with theoretical predictions, both for stiffness and strength, and an even better agreement can be achieved if a correction for taking the contour lines into account is implemented.
Originality/value
The paper shows that also the tensile strength of FDM parts can be predicted by using a mathematical model based on CLT. This opens up the possibility of using CLT for studying optimization of raster filled lay-ups, for example in terms of the best raster angles sequence, to better resist applied external loads.
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M. Rahmani Kalestan, H. Moayeri Kashani, A. Pourkamali Anaraki and F. Ashena Ghasemi
The purpose of this paper is to use the fiber metal laminates (FML) composites as a patch for repairing a single notched specimen made of AL1035 aluminum alloy. The FML composite…
Abstract
Purpose
The purpose of this paper is to use the fiber metal laminates (FML) composites as a patch for repairing a single notched specimen made of AL1035 aluminum alloy. The FML composite patch was bonded on one side of the cracked specimens by adhesive Araldite 2015. Then the fatigue crack growth tests were conducted on the specimens and the effects of both FML patch lay-up sequence and pre-crack angle on the fatigue life were investigated. Finally, the effect of repairing on the fracture parameters (SIF and crack propagation direction) at the crack front has also been calculated using three-dimensional finite element analysis.
Design/methodology/approach
The fatigue crack growth tests were conducted on the specimens and the effects of both FML patch lay-up sequence and pre-crack angle on the fatigue life were investigated.
Findings
The results show that the fatigue life of the patched specimens with inclined crack increased approximately 2-6.02 times compared to the un-patched specimens. In addition, the fatigue crack growth rate decreased significantly when the patch was used. Generally, the FML patch with Plate-Fiber-Fiber-AL lay-up has more efficiency than other lay-up sequences.
Originality/value
Recently, composite patches are used in the structure repair processes to increase the service life of cracked components. The bonded patch method is one of the efficient methods among repairing methods. Today, the FMLs are used in the aircraft structures as a replacement of high-strength aluminum alloys due to their lightweight and high-strength properties. Many researches have been performed on single and double side repaired panels using composite patches. In this study, the FML composites have been used as a patch for repairing a single notched specimen made of AL1035 aluminum alloy.
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S. Vali-Shariatpanahi, S. Noroozi and J. Vinney
This paper presents the results from a study of the in-plane (interlamina) shear characteristics of specific CFRP with a particular balanced lay-up of 12 ply cured laminates. This…
Abstract
This paper presents the results from a study of the in-plane (interlamina) shear characteristics of specific CFRP with a particular balanced lay-up of 12 ply cured laminates. This study involved a detailed experimental program to determine the material properties. The material properties were used for the failure analysis of a new type of fastener joint for composite laminates, which has a potential use in the aerospace industry. Twenty shear tests were carried out using a minimum of 6 specimens for every lay-up. Although some thickness tolerances issues were caused by using different laminate lay-ups, all other geometric parameters were kept similar. Ply failures were observed for 45°/90°, 45°, 90° specimens. An FE model was also developed for each particular lay-up and compared against the test data. It was also used to determine why each coupon failed in a certain way. The FE model uses 2D unsymmetrical material properties with shell elements representing the thickness. In terms of boundary conditions the model was constrained at one end of the specimen and in two directions with a compressive load applied at the other end.
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Describes the benefits of using robots for advanced composite lay‐up procedures. Particular emphasis is on aerospace structures. Argues that the use of robots now makes viable…
Abstract
Describes the benefits of using robots for advanced composite lay‐up procedures. Particular emphasis is on aerospace structures. Argues that the use of robots now makes viable many fabrication operations that were previously too expensive, and highlights the improved quality afforded by consistent and rapid, automated lay‐up procedures.
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Gang Zhou, Bolun Zhang and Aimee Pasricha
The indentation behaviour of sandwich panels is significant to incipient damage and is known to be affected by a number of dominant parameters. However, it is challenging not only…
Abstract
Purpose
The indentation behaviour of sandwich panels is significant to incipient damage and is known to be affected by a number of dominant parameters. However, it is challenging not only to demonstrate how those few dominant parameters influence the indentation behaviour but also to ascertain that such influence was coupled to the variation of the other dominant parameters. The paper aims to discuss these issues.
Design/methodology/approach
In this work, the authors adopted a controllable quasi-static testing to carry out a diagnostic interrogation on the nature of incipient damage in laminate-skinned sandwich panels using hemispherical indenter and used photographs taken from the cross-sections of all the cut-up tested specimens, which were stopped both just before and after the initial critical loads, respectively, to confirm the mechanism of the incipient damage. Sandwich panels with aluminium honeycomb core had carbon/epoxy skins of two different thicknesses and lay-ups and hemispherical nosed indenter had three different diameters.
Findings
The authors found that: the incipient damage mechanism in all the panels was combined delamination in the skin and core crushing without debonding; doubling the skin thickness had the significant enhancement on critical load and indentation and this enhancement became greater for the larger indenter diameters; the indenter diameter had the moderate effect on critical load in the thick panels from 8 to 14 mm but had the negligible effect on thin panels and no effect on the thick panels from 14 to 20 mm; varying the skin lay-up or support had little effect on the indentation behaviour.
Research limitations/implications
These findings were limited to the constant core density and core thickness. Varying the former significantly could alter the findings accordingly.
Practical implications
The results of this work should be tremendously useful to design and analysis in industrial applications of sandwich structures in aircraft, vehicles, marine vessels and transport carriages for situations involving localised loading and deformation.
Originality/value
The results of this research work is one of the very few that demonstrated a systematic understanding of the indentation behaviour characteristics of sandwich construction, which is vital to the establishment of indentation law for sandwich structures in future.
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Russo Swart, Feras Korkees, Peter Dorrington and Joshua Thurman
Composites 3D printing has the potential to replace the conventional manufacturing processes for engineering applications because it allows for the manufacturing of complex shapes…
Abstract
Purpose
Composites 3D printing has the potential to replace the conventional manufacturing processes for engineering applications because it allows for the manufacturing of complex shapes with the possibility of reducing the manufacturing cost. This paper aims to analyse the performance of 3D printed fibre reinforced polymer composites to investigate the energy absorption capabilities and the residual properties before and after impact.
Design/methodology/approach
Various composites composed of carbon fibres and Kevlar fibres embedded into both Onyx and nylon matrix were printed using Markforged-Two 3D printers. Specimens with different fibre orientations and fibre volume fractions (Vf) were printed. A drop-weight impact test was performed at energies of 2, 5, 8 and 10 J. Flexural testing was performed to evaluate the flexural strength, flexural modulus and absorbed energy under bending (AEUB) before and after impact. Additionally, 3D printed carbon fibre composites were tested at two different temperatures to study their behaviour under room and sub-ambient temperatures. Failure modes were investigated using optical and high depth of field microscopes for all 3D printed composite samples.
Findings
Kevlar/nylon composites with a unidirectional lay-up and 50% Vf exhibited the most prominent results for AEUB at room temperature. The high-Vf carbon fibre composite showed the highest ultimate strength and modulus and performed best at both temperature regimes.
Originality/value
The work, findings and testing produced in this paper are entirely original with the objective to provide further understanding of 3D printed composites and its potential for use in many applications.
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Tony Williams, Brian Birchall and Julian Rishton
Composite design software is helping engineers from British Aerospace to reduce significantly engineering time on composite parts for the Eurofighter 2000 aircraft. FiberSIM’…
Abstract
Composite design software is helping engineers from British Aerospace to reduce significantly engineering time on composite parts for the Eurofighter 2000 aircraft. FiberSIM’ simulation software from Composite Design Technologies (CDT), Waltham, Massachusetts, allows manufacturing engineers to define the composite lay‐up on a computer, eliminating the old, industry‐wide trial and error process that was used to lay composite plies onto a complex surface. The new technology ensures that manufacturing reflects the design intent and reduces weight by avoiding unnecessary patches. British Aerospace also expects additional production time savings by using the software to program laser projection equipment.
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J. Sorić and I. Smojver
A linear and geometrically non‐linear computation of a laminatedcomposite torispherical shell subjected to internal pressure was performed byusing the layered finite element whose…
Abstract
A linear and geometrically non‐linear computation of a laminated composite torispherical shell subjected to internal pressure was performed by using the layered finite element whose formulation is based on degeneration principle. Geometric non‐linearity in terms of large deformations with total Lagrangian formulation was taken into account. The effect of the lamination schemes on geometric non‐linear behaviour and stress resultant distributions was analysed. The fibre directions have not a great influence on the shape of the load‐displacement curves. In contrast to the hoop stress resultant distribution, the moment distribution is significantly influenced by the lamination schemes. The influence of the lamination schemes on bending moments is greater in non‐linear than in linear computations. Likewise, the effect of the fibre orientation is greater on the hoop than on the meridional moment distribution. In unsymmetric laminated shells the values of the hoop moments exceed those of the meridional moments which is a considerable difference from metallic isotropic shells.
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Abstract
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