scholarly journals Detection and Imaging of Damages and Defects in Fibre-Reinforced Composites by Resonance Magnetic Technique

2020 ◽  
Author(s):  
Carine Alves ◽  
Janete Oliveira ◽  
Alberto Tannus ◽  
Alessandra Tarpani ◽  
José Tarpani
Keyword(s):  
Composite Laminates ◽  
Saline Solution ◽  
Pulse Sequences ◽  
Image Interpretation ◽  
Reinforced Composites ◽  
Electrically Conductive ◽  
Distribution Shape ◽  
Non Destructive ◽  
Magnetic Resonance Imaging Equipment ◽  
Fibre Reinforced Composites

Defectively manufactured and deliberately damaged composite laminates fabricated with different continuous reinforcing fibres (respectively, carbon and glass) and polymer matrices (respectively, thermoset and thermoplastic) were inspected in magnetic resonance imaging equipment. Two pulse sequences were evaluated during non-destructive examination conducted in saline solution-immersed samples to simulate load-bearing orthopaedic implants permanently in contact with biofluids. The orientation, positioning, shape, and especially the size of translaminar and delamination fractures were determined according to stringent structural assessment criteria. The spatial distribution, shape, and contours of water-filled voids were sufficiently delineated to infer the amount of absorbed water if thinner image slices than this study were used. The surface texture of composite specimens featuring roughness, waviness, indentation, crushing, and scratches was outlined, with fortuitous artefacts not impairing the image quality and interpretation. Low electromagnetic shielding glass fibres delivered the highest, while electrically conductive carbon fibres produced the poorest quality images, particularly when blended with thermoplastic polymer, though reliable image interpretation was still attainable.

scholarly journals Detection and Imaging of Damages and Defects in Fibre-Reinforced Composites by Magnetic Resonance Technique

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 977
Author(s):  
Carine Alves ◽  
Janete Oliveira ◽  
Alberto Tannus ◽  
Alessandra Tarpani ◽  
José Tarpani
Keyword(s):  
Magnetic Resonance ◽  
Composite Laminates ◽  
Pulse Sequences ◽  
Image Interpretation ◽  
Electrically Conductive ◽  
Distribution Shape ◽  
Magnetic Resonance Technique ◽  
Non Destructive ◽  
Magnetic Resonance Imaging Equipment ◽  
Fibre Reinforced Composites

Defectively manufactured and deliberately damaged composite laminates fabricated with different continuous reinforcing fibres (respectively, carbon and glass) and polymer matrices (respectively, thermoset and thermoplastic) were inspected in magnetic resonance imaging equipment. Two pulse sequences were evaluated during non-destructive examination conducted in saline solution-immersed samples to simulate load-bearing orthopaedic implants permanently in contact with biofluids. The orientation, positioning, shape, and especially the size of translaminar and delamination fractures were determined according to stringent structural assessment criteria. The spatial distribution, shape, and contours of water-filled voids were sufficiently delineated to infer the amount of absorbed water if thinner image slices than this study were used. The surface texture of composite specimens featuring roughness, waviness, indentation, crushing, and scratches was outlined, with fortuitous artefacts not impairing the image quality and interpretation. Low electromagnetic shielding glass fibres delivered the highest, while electrically conductive carbon fibres produced the poorest quality images, particularly when blended with thermoplastic polymer, though reliable image interpretation was still attainable.

scholarly journals Ultrasonic Non-Destructive  Testing of Fibre Reinforced  Composites

2021 ◽  
Author(s):  
◽  
Matthew Thomson
Keyword(s):  
Experimental Work ◽  
Rayleigh Waves ◽  
Ultrasonic Waves ◽  
Reinforced Composites ◽  
Surface Cracks ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Reinforced Composite ◽  
Non Destructive ◽  
Fibre Reinforced Composites

<p>This thesis focuses on the application of high frequency ultrasound as a tool for performing non-destructive testing for pultruded fibre reinforced composite (FRC) rods. These composite rods are popular in the manufacturing, construction and electrical industries due to their chemical, electrical and strength properties. Such FRCs are manufactured on automated production lines that operate day and night. Non-destructive testing techniques are desired to quickly and accurately detectmanufacturing flaws such as coating thickness irregularities and surface cracks. Layers and cracks can present as large changes in acoustic impedance and will strongly reflect ultrasonic waves. Combined with their low cost, east of use and absense of potentially harmful radiation, ultrasound has proven popular worldwide for Non-Destructive Testing. Finite Element Analysis (FEA) was employed to investigate the propagation of ultrasonic waves through layers of material to simulate a thickness measurement and the ability of ultrasound to measure thicknesses was proven. Experimental work was conducted on two fibre reinforced composite samples with varying thickness coatings of plastic and paint. The thickness was measured accurately using immersion transducers at 50MHz and a resolution of 20μm was attained through the use of matched filtering techniques. Surface acoustic waves, particularly Rayleigh waves were investigated using FEA techniques so that the generation, scattering and detection of such waves was understood. This lead to the development of methods for detecting surface cracks in glass using Rayleigh waves and these methods were successfully used in experimental work. Wave propagation in fibre reinforced composites was modelled and experimentally investigated with the results confirming theoretical expectations. Finally a Rayleigh wave was launched onto a fibre reinforced composite sample however the amount of energy leakage into the water was so great, due to the acoustic impedance of water, the detection of the wave was prevented. The conclusion reached was that an immersion setup was not appropriate for launching a travelling Rayleigh wave.</p>

The significance of damage and defects and their detection in composite materials: A review

1992 ◽  
Vol 27 (1) ◽  
pp. 29-42 ◽  
Author(s):  
W J Cantwell ◽  
J Morton
Keyword(s):  
Composite Materials ◽  
Damage Detection ◽  
Failure Modes ◽  
Fracture Mechanisms ◽  
Reinforced Composites ◽  
Load Bearing ◽  
Fibre Composites ◽  
Non Destructive ◽  
Fibre Reinforced Composites ◽  
Non Destructive Techniques

In this paper the various failure modes which occur in long fibre composites are described and discussed. The significance of each of these fracture mechanisms, in terms of their energy-dissipating capacity as well as their effect on the residual load-bearing properties, is considered. A brief review of both the destructive and non-destructive techniques used for detecting and characterizing defects and damage is presented. The ability of each technique to identify the various fracture mechanisms involved in the failure of long fibre reinforced composites is discussed and their overall suitability for damage detection evaluated.

A simple portable low-pressure healant-injection device for repairing damaged composite laminates

2017 ◽  
Vol 45 (4) ◽  
pp. 360-375 ◽  
Author(s):  
WL Lai ◽  
AYH Cheah ◽  
RCO Ruiz ◽  
NGW Lo ◽  
KQJ Kuah ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Composite Laminates ◽  
Low Pressure ◽  
Reinforced Composites ◽  
Injection Device ◽  
Destructive Testing ◽  
Micro Cracks ◽  
Flow Through ◽  
Injection Unit ◽  
Fibre Reinforced Composites

This article presents the outcomes of an undergraduate design-for-industry team-driven project to develop a portable low-pressure healant-injection device. The developed healant-injection device is intended to use for teaching purpose. The students practice some of the techniques of repairing damaged composite laminates, as part of an engineering composite-related course, which mainly covers the fundamentals and applications of composite laminates. The healant-injection device works by introducing resin into damaged site that can assist the healant to flow through the network of micro-cracks in a low-pressure environment. The device comprises three components: a chamber featuring a (rectangular box) cover made from acrylic that is intended to cover a damaged surface in a low-pressure environment, an injection unit and a vacuum pump unit. Only the vacuum chamber was designed from scratch by the team; the other components were sourced commercially. The repair of composite laminates can be performed using a low viscosity resin, which is made to flow through a hole on the roof of the chamber, assisted by the injection unit (fluid dispenser), from which the resin flows into the damaged (micro-cracks) site; the very low pressure environment (25–29 inHg) in the chamber facilitates the removal of air pockets in the cracks. The composite laminates featured in this project are carbon fibre reinforced composite laminates, which are of great interest to the aerospace industry. Testing and evaluation were carried out by the team to assess the performance of the healant-injection device using impacted carbon fibre reinforced composites. To assist the team to study the effectiveness of the repair, (a) an ultrasonic C-scan equipment for non-destructive testing was used to assess the extent of the healant flow into the crack regions within the damaged carbon fibre reinforced composites and (b) a compression after impact test was carried out to assess the recovery of the compressive strength of the repaired carbon fibre reinforced composites compare to the pristine and damaged samples in different number of carbon-fibre plies (10, 16, 24 and 32).

Recent Developments in Modelling of Progressive Damage in Fibre-Reinforced Composites

2015 ◽  
Vol 784 ◽  
pp. 274-283
Author(s):  
Bo Yang Chen ◽  
Tong Earn Tay
Keyword(s):  
Composite Laminates ◽  
Progressive Damage ◽  
Reinforced Composites ◽  
Matrix Cracks ◽  
Reinforced Composite ◽  
Recent Developments ◽  
Open Hole ◽  
Tension And Compression ◽  
And Migration ◽  
Fibre Reinforced Composites

This paper provides an overview of recent developments in the modeling of progressive damage in fiber-reinforced composite laminates. Some insights into modeling the size effects of open-hole composite laminates under in-plane tension and compression, the significance of ply-blocking and delamination are discussed. Recent interest in the interaction and migration of matrix cracks and delamination, resulting in development of integrated XFEM-CE and floating node methods will also be presented.

Electrostatic Dissipative Glass Fibre Reinforced Composites

2006 ◽  
Vol 312 ◽  
pp. 123-126
Author(s):  
C. Gloria-Esparza ◽  
J. Zurek ◽  
Qiang Yuan ◽  
Stuart Bateman ◽  
Kenong Xia
Keyword(s):  
Glass Fibre ◽  
Reinforced Composites ◽  
Electrically Conductive ◽  
Conductive Composites ◽  
Single Screw Extruder ◽  
Short Glass Fibre ◽  
Glass Fibre Reinforced ◽  
Glass Fibre Reinforced Composites ◽  
Short Glass ◽  
Fibre Reinforced Composites

Electrically conductive composites were made from short glass fibre (GF) and carbon black (CB) blended with high-density polyethylene (HDPE) using a single screw extruder. The Young’s modulus, tensile and impact strengths were improved with the addition of GF, and the surface conductivity in the static dissipative range of 10-6 to 10-9 S was achieved at CB content as low as 1 wt%, significantly lower than that in the unreinforced CB/HDPE. Addition of a coupling agent (MAPE) improved bonding between fibres and the polymer matrix and increased the stiffness and fracture resistance.

scholarly journals Composite Laminates with Recycled Carbon Fibres and Carbon Nanotubes

2020 ◽  
Vol 57 (1) ◽  
pp. 86-91
Author(s):  
Loredana Santo ◽  
Denise Bellisario ◽  
Leandro Iorio ◽  
Claudia Papa ◽  
Fabrizio Quadrini ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Composite Laminates ◽  
Resin Matrix ◽  
Reinforced Composites ◽  
Carbon Fibres ◽  
Industrial Equipment ◽  
Bending Tests ◽  
Mechanical Measurements ◽  
Unfilled Resin ◽  
Fibre Reinforced Composites

Carbon fibre reinforced composites were manufactured by using recycled carbon fibres (CF) and carbon nanotubes (CNT). Dry fabrics were impregnated by hot melting with 1 wt% CNT filled epoxy resin to produce prepregs. Subsequently, composite laminates were manufactured by vacuum bagging and autoclave moulding. Only materials and industrial equipment were used for the laminate production. Laminates with unfilled resin and virgin CFs were also manufactured for comparison. Samples were extracted for physical and mechanical measurements. Dynamic mechanical analyses and bending tests were carried out to evaluate the interaction between CNTs, resin matrix and recycled CFs.

scholarly journals Ultrasonic Non-Destructive  Testing of Fibre Reinforced  Composites

2021 ◽  
Author(s):  
◽  
Matthew Thomson
Keyword(s):  
Experimental Work ◽  
Rayleigh Waves ◽  
Ultrasonic Waves ◽  
Reinforced Composites ◽  
Surface Cracks ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Reinforced Composite ◽  
Non Destructive ◽  
Fibre Reinforced Composites

<p>This thesis focuses on the application of high frequency ultrasound as a tool for performing non-destructive testing for pultruded fibre reinforced composite (FRC) rods. These composite rods are popular in the manufacturing, construction and electrical industries due to their chemical, electrical and strength properties. Such FRCs are manufactured on automated production lines that operate day and night. Non-destructive testing techniques are desired to quickly and accurately detectmanufacturing flaws such as coating thickness irregularities and surface cracks. Layers and cracks can present as large changes in acoustic impedance and will strongly reflect ultrasonic waves. Combined with their low cost, east of use and absense of potentially harmful radiation, ultrasound has proven popular worldwide for Non-Destructive Testing. Finite Element Analysis (FEA) was employed to investigate the propagation of ultrasonic waves through layers of material to simulate a thickness measurement and the ability of ultrasound to measure thicknesses was proven. Experimental work was conducted on two fibre reinforced composite samples with varying thickness coatings of plastic and paint. The thickness was measured accurately using immersion transducers at 50MHz and a resolution of 20μm was attained through the use of matched filtering techniques. Surface acoustic waves, particularly Rayleigh waves were investigated using FEA techniques so that the generation, scattering and detection of such waves was understood. This lead to the development of methods for detecting surface cracks in glass using Rayleigh waves and these methods were successfully used in experimental work. Wave propagation in fibre reinforced composites was modelled and experimentally investigated with the results confirming theoretical expectations. Finally a Rayleigh wave was launched onto a fibre reinforced composite sample however the amount of energy leakage into the water was so great, due to the acoustic impedance of water, the detection of the wave was prevented. The conclusion reached was that an immersion setup was not appropriate for launching a travelling Rayleigh wave.</p>

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