Acoustic Emission Monitoring of Defects in Buckling CFRP Composite Panels

2006 ◽  
Vol 13-14 ◽  
pp. 259-266 ◽  
Author(s):  
Mark J. Eaton ◽  
Karen M. Holford ◽  
C.A. Featherston ◽  
Rhys Pullin
Keyword(s):  
Acoustic Emission ◽  
Carbon Fibre ◽  
Optical Measurement ◽  
Impact Damage ◽  
Fibre Composite ◽  
Carbon Fibre Composite ◽  
Premature Failure ◽  
Full Field ◽  
Cfrp Composite ◽  
Acoustic Emission Sensors

The presence of impact damage in a carbon fibre composite can reduce its capacity to support an in-plane load, which can lead to an unexpected or premature failure. This paper reports on an investigation into two slender carbon/fibre epoxy panels, one un-damaged and one with an artificial delamination introduced using an embedded section of PTFE. The reported tests form part of a larger series of investigations using differing sizes of artificial delamination and real impact damage. An investigation of wave velocity propagation at varying angles to the composite lay up was completed to assist in source location. The specimens were loaded under, uniaxial in-plane loading and monitored using four resonant acoustic emission sensors. A full field optical measurement system was used to measure the global displacement of the specimens. Analysis of AE waveforms and AE hit rate were used to assess the buckling of the panel. The results compared favourably with the optical measurement results.

scholarly journals CONCRETE, REINFORCED BY CARBON FIBRE COMPOSITE STRUCTURE, LOAD BEARING CAPACITY DURING CRACKING

2021 ◽  
Vol 2 ◽  
pp. 232-237
Author(s):  
Krishna Kiran Annamaneni ◽  
Bhumika Vallabhbhai Dobariya ◽  
Krasnikovs Andrejs
Keyword(s):  
Carbon Fibre ◽  
Fibre Composite ◽  
Plain Concrete ◽  
Carbon Fibre Composite ◽  
Natural Sand ◽  
Load Bearing ◽  
Study Approach ◽  
Concrete Mix ◽  
Cfrp Composite ◽  
Carbon Fibre Reinforced Plastic

Different authors conducted studies on fiber reinforced concretes (FRC) with carbon fibres of different lengths and some results showed that concrete mix with homogeneously distributed short fibres in their volume have good strength and ultra-strain compared to normal plain concrete mix. However, this study is focused more on 3-dimensional (3D) carbon fibre reinforced plastic (epoxy) CFRP composite thin rods frame used as a reinforcement in concrete which shows good increase in loadbearing and ductility. Were investigated concrete mixes with superplasticizer, nano-silica, quartz sand, fine natural sand and gravels. Diagonal cross bracing carbon fibre epoxy frames were used as a reinforcement giving better ductility results. Proposed study approach is to show that the reinforced concrete with provided materials have an increased performance in terms of ductility, sustainability, and load bearing in cracked statement. Total, four groups of concrete and each group with three beams were casted and tested in this experiment, three groups with three different shapes of carbon frames and three beams without frames to compare the mechanical properties after 28 days. Failure mechanisms in any particular case were analysed.  

Classification of Delamination and Matrix Cracking in Carbon Fibre Composite Plates Using Acoustic Emission (AE)

2009 ◽  
Author(s):  
Dirk Aljets ◽  
Alex Chong ◽  
Steve Wilcox ◽  
Karen Holford ◽  
Rhys Pullin ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Carbon Fibre ◽  
Composite Structures ◽  
Failure Modes ◽  
Fibre Composite ◽  
Composite Plates ◽  
Matrix Cracking ◽  
Actual Condition ◽  
Carbon Fibre Composite ◽  
Failure Types

Recent publications show that there is an increasing interest in the aircraft industry in monitoring the actual condition of a structure in real time and while the structure is in service. It is hoped that this Structural Health Monitoring (SHM) could make some regular inspections unnecessary and allow maintenance only when required. This is particularly important for CFRP structures for which aircraft manufacturers are increasingly interested. For these new composite structures where the experience of fatigue failure is relatively low, this technique could potentially be economical and improve the safety of the structures. Acoustic Emission is reported to be sensitive to the four failure types in composite materials, namely matrix cracking, delamination, debonding and fibre fracture. These failure modes can have different impacts on structural integrity and it is therefore of interest to identify these failure types before further maintenance steps are conducted. This report discusses different features in AE signals which can be used to identify the actual flaw type. These features were then applied to AE data collected from two different experiments on carbon fibre composite plates. These experiments were designed to induce the two different failure modes of matrix cracking and delamination. The data collected was used to train a neural network to recognise the two failure modes.

scholarly journals A repairable carbon nanotube web-based electro-thermal heater and damage sensor for aerospace applications

2021 ◽  
pp. 1-11
Author(s):  
X. Yao ◽  
S.C. Hawkins ◽  
B.G. Falzon
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fibre ◽  
Infrared Imaging ◽  
Impact Damage ◽  
Fibre Composite ◽  
Leading Edge ◽  
Cold Spot ◽  
Loss Of Function ◽  
Carbon Fibre Composite ◽  
Web Based

ABSTRACT We previously described an efficient, lightweight and flexible electro-thermal system, based on directly drawn carbon nanotube web (CNT web), as part of an icing protection system for carbon fibre reinforced polymer (CFRP) composite aircraft structures. The location of the heating elements on critical lifting surface leading edges or nacelle intake lips makes them particularly susceptible to impact damage, which may leave no visible mark. This makes it desirable to have both a mechanism for identifying the location of damage to the CNT structure (and by inference, potential damage to the underlying CFRP) and a process for restoring the CNT heater to full operation. With the CNT web acting as a sensor, impact damage is identified by an increase in electrical resistance and, particularly, by infrared imaging, which reveals a cold spot or zone depending upon the CNT web layup. Whereas a unidirectional CNT web layup exhibits a large increase in resistance and loss of a full width band of operation, a cross ply quasi-isotropic CNT web arrangement suffers only a small increase in resistance and a loss of function that is highly localised to the damaged area. A novel methodology, based on dispersed CNT in resin, is described for repairing and reconnecting the CNT structure and restoring functionality. A CNT web-based electro-thermal element was applied to the leading edge of a representative carbon-fibre composite wing section to demonstrate the flexibility of this system.

Carbon fibre composite development for in-ground UAV’s with NACA0012 aerofoil wing

2021 ◽  
Author(s):  
Ajanas Saludheen ◽  
Firaz Muhammed Zakariya ◽  
M Ankith ◽  
Nirmal Nandakumar ◽  
Jais George ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Fibre Composite ◽  
Carbon Fibre Composite
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