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 ◽  
...  

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).

Author(s):  
Sérgio Luiz Moni Ribeiro Filho ◽  
Túlio Hallak Panzera ◽  
Lincoln Cardoso Brandão ◽  
Alexandre Mendes Abrão

2014 ◽  
Vol 2 (17) ◽  
pp. 6231 ◽  
Author(s):  
Samuel Lörcher ◽  
Thomas Winkler ◽  
Katarzyna Makyła ◽  
Claudiane Ouellet-Plamondon ◽  
Ingo Burgert ◽  
...  

2021 ◽  
Author(s):  
◽  
Matthew Thomson

<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>


2021 ◽  
Vol 2021 ◽  
pp. 102-108
Author(s):  
J. Domenech-Pastor ◽  
P. Diaz-Garcia ◽  
D. Garcia

Composites are materials formed by the combination of two or more components that acquire better properties than the ones obtained by each component on its own. Composites have been widely used in the industry due to its light weight and good mechanical properties. To improve these properties several layers of reinforced material (e.g., carbon fibre) are overlapped which produce an increase in the fibre consumption. In this sense Tailored Fibre Placement (TFP) embroidery can offer good opportunity to reduce the consumption of reinforced fibre while improving the mechanical properties due to the alignment of the fibres in the effort direction. This study analyzes the performance of carbon fibre reinforced composites with Polyester resin made with TFP embroidery technology against flexural strength efforts and without using plain woven fabrics to demonstrate that the use of reinforcement fabrics in composites can be optimized by a curved alignment of the fibers. Two different structures were embroidered with TFP technology, one simulating a woven fabric with straight unidirectional alignment of fibres in horizontal and vertical direction, and a second structure made with curvilinear alignment of carbon fibers. After the study of the flexural mechanical properties an improvement of 18% was obtained in maximum flexural strength.


2016 ◽  
Vol 2 ◽  
pp. 96-103 ◽  
Author(s):  
Declan Carolan ◽  
A.J. Kinloch ◽  
A. Ivankovic ◽  
S. Sprenger ◽  
A.C. Taylor

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