C. Featherston - Academia.edu (original) (raw)

Papers by C. Featherston

Research paper thumbnail of Damage classification in carbon fibre composites using acoustic emission: A comparison of three techniques

Composites Part B: Engineering, 2015

Classifying the type of damage occurring within a structure using a structural health monitoring ... more Classifying the type of damage occurring within a structure using a structural health monitoring system can allow the end user to assess what kind of repairs, if any, that a component requires. This paper investigates the use of acoustic emission (AE) to locate and classify the type of damage occurring in a composite, carbon fibre panel during buckling. The damage was first located using a bespoke location algorithm developed at Cardiff University, called delta-T mapping. Signals identified as coming from the regions of damage were then analysed using three AE classification techniques; Artificial Neural Network (ANN) analysis, Unsupervised Waveform Clustering (UWC) and corrected Measured Amplitude Ratio (MAR). A comparison of results yielded by these techniques shows a strong agreement regarding the nature of the damage present in the panel, with the signals assigned to two different damage mechanisms, believed to be delamination and matrix cracking. Ultrasonic C-scan images and a digital image correlation (DIC) analysis of the buckled panel were used as validation. MAR's ability to reveal the orientation of recorded signals greatly assisted the identification of the delamination region, however, ANN and UWC have the ability to group signals into several different classes, which would prove useful in instances where several damage mechanisms were generated. Combining each technique's individual merits in a multi-technique analysis dramatically improved the reliability of the AE investigation and it is thought that this cross-correlation between techniques will also be the key to developing a reliable SHM system.

Research paper thumbnail of Structural Health Monitoring of Composite Structures Using Embedded Transducers

Research paper thumbnail of ACOUSTIC EMISSION MONITORING OF BUCKLING BEHAVIOUR IN IMPACT-DAMAGED COMPOSITE PLATES

Research paper thumbnail of Buckling and Postbuckling of Impact Damaged Composite Plates

This paper describes tests to examine the buckling behaviour of a carbon fibre panel subject to d... more This paper describes tests to examine the buckling behaviour of a carbon fibre panel subject to damage via an impact load, simply supported along all four edges and loaded in uniaxial compression. The buckling shape was monitored using a geometrical Moiré fringe technique and these experimental results were compared with a finite element model. The correlation between the experimental results and the model was very good and provided confirmation of the relevance of the geometric monitoring technique for observing the buckling behaviour of such panels. The test was also continuously monitored using resonant acoustic emission (AE) sensors mounted directly on the composite panel. AE parametric data was recorded together with waveforms for events above 60dB. Time-of-arrival methods were used to locate the sources of events in the panel. The results of the AE monitoring indicated that no further damage due to delamination was induced in the panel as a result of this test. Subsequent ultrasonic scanning of the panel confirmed this finding. The AE results also indicated sources of acoustic emission that corresponded with bending in the panel and it is postulated that AE is a useful technique for identification of bending in panels, allowing buckling modes to be identified and monitored.

Research paper thumbnail of An Investigation of Frequency as an Acoustic Emission Signal Discriminator in Carbon Fibre Composite Materials

This work considers the use of frequency content as a discriminating factor for AE signals from c... more This work considers the use of frequency content as a discriminating factor for AE signals from carbon fibre composites. An artificial AE source generated by a conical transducer was used to investigate the effects of specimen geometry and sensor response on the frequency content of recorded signals. Additionally, AE signals were recorded from different damage mechanisms in tensile and beam buckling coupon specimens. The peak frequency content was used to examine signals resulting from the different damage modes observed and observations were in general agreement with previous research studies. However, it was shown that great care is required when using peak frequency content as a discriminating factor because geometry and sensor response have a significant effect on the frequency content of a recorded signal.

Research paper thumbnail of AE WAVE PROPAGATION AND NOVEL SOURCE LOCATION IN COMPOSITE PLATES

Source location in carbon-fibre composite structures is very complex because the wave velocity is... more Source location in carbon-fibre composite structures is very complex because the wave velocity is dependent on the direction of propagation relative to the fibre lay-up. The problem is further complicated by signal attenuation and dispersion. This paper reports on an investigation into signal propagation and source location in carbon-fibre composite plates.

Research paper thumbnail of Imperfection Sensitivity In Plates -An Assessment Using DIC

This paper examines the effect of imperfections on the behaviour of a series of panels, simply su... more This paper examines the effect of imperfections on the behaviour of a series of panels, simply supported along all four edges, and subject to compressive in-plane loading. In each case Digital Image Correlation (DIC) is used to determine the initial profile and set-up of the structure and to monitor its behaviour during test. The data is used to automatically generate a series of meshes representative of each of these specimens, suitable for analysis using Finite Element Analysis. Comparison of the results obtained from these analyses with those found during the experiments modelled shows an improved correlation when compared with standard techniques for assessing imperfection sensitivity. Set-up is straightforward and models can be obtained quickly based on the data collected.

Research paper thumbnail of Free vibration analysis of beams and frames with multiple cracks for damage detection

Journal of Sound and Vibration, 2014

ABSTRACT The problem of calculating the natural frequencies of beams with multiple cracks and fra... more ABSTRACT The problem of calculating the natural frequencies of beams with multiple cracks and frames with cracked beams is studied. The natural frequencies are obtained using a new method in which a rotational spring model is used to represent the cracks. For beams, dynamic stiffness matrices of order 4 are obtained in a recursive manner, according to the number of cracks, by applying partial Gaussian elimination. The Wittrick–Williams algorithm is used to compute the natural frequencies in the resulting transcendental eigenvalue problem. Published numerical examples for cracked beams are used for validation. The global dynamic stiffness matrix of a frame with multiply cracked members is then assembled. A published two bay frame example is used to evaluate the new method. The effect of changing the location of a crack in a two bay two storey frame is studied numerically, giving insight into the inverse problem of damage detection.

Research paper thumbnail of Detection and Location of Impact Damage using Acoustic Emission

Impact damage is one of the greatest weaknesses of composite materials and efforts taken to impro... more Impact damage is one of the greatest weaknesses of composite materials and efforts taken to improve its understanding, analysis and prevention have slowed the introduction of composite materials to large-scale and safety critical structures. In order to make this step, operators must be able to ensure the structural integrity and safe operation of composite structures during long service lives. One such approach to this is the use of Structural Health Monitoring (SHM) to continuously monitor the condition of a structure. In this paper a novel mapping based acoustic emission (AE) source location technique is used to detect and locate impact events on a carbon fibre composite panel.

Research paper thumbnail of Approaches to acoustic emission monitoring with applicability to key components in wind turbines

Research paper thumbnail of Towards the development of lightweight structural health monitoring systems for aerospace applications

Research paper thumbnail of Rapid text referral

A 23-year-old soldier developed a facial ulcer after returning from Belize. The possibility of cu... more A 23-year-old soldier developed a facial ulcer after returning from Belize. The possibility of cutaneous leishmaniasis prompted referral to our unit. The lesion was photographed with a mobile phone and texted to a secure webpage with password access (fi gure). The images supported the diagnosis of cutaneous leishmaniasis and the patient was admitted. The diagnosis was confi rmed histologically and the parasites found to be Leishmania braziliensis. The patient was treated as an inpatient with a standard regimen of 20 mg/kg of intravenous sodium stibogluconate for 20 days. This therapy led to an uneventful recovery, with no relapse at 6 months follow-up.

Research paper thumbnail of Thermoelectric energy harvesting for wireless sensor systems in aircraft

Research paper thumbnail of Harvesting vibration energy for structural health monitoring in aircraft

... Test-Rig. The panel was tested using the rig shown in Fig. 2a. ... The frame had a mass of ap... more ... Test-Rig. The panel was tested using the rig shown in Fig. 2a. ... The frame had a mass of approximately 22kg in order to prevent the loss of vibration energy by the displacement of the frame. Fig. 2 Test Rig a) frame with panel mounted b) position of energy harvesting devices ...

Research paper thumbnail of Modelling the effects of geometric imperfections on the buckling and initial post-buckling behaviour of flat plates under compression using measured data

ABSTRACT Recent developments in optical techniques have allowed accurate representations of the... more ABSTRACT Recent developments in optical techniques have allowed accurate representations of the geometry of test specimens to be obtained. These enable the nature of geometric imperfections resulting from manufacture or set-up to be captured in a form which allows them to be incorporated directly into models generated to predict the behaviour of the structure. This study examines the effect of such imperfections on the behaviour of a series of panels, simply supported along all four edges, and subject to uniaxial compressive in-plane loading. In each case, digital image correlation is used to determine the initial profile and set-up of the panel and to monitor its behaviour during test. The data are used to automatically generate a series of meshes representative of each of the specimens tested, suitable for finite element analysis. Comparison of the results obtained from these analyses with those found during the experiments modelled shows an improved correlation when compared with standard techniques for assessing imperfection sensitivity. Set-up is straightforward, and models can be obtained quickly based on the data collected.

Research paper thumbnail of Automated Damage Detection in Composite Components Using Acoustic Emission

Key Engineering Materials, 2013

ABSTRACT The ability of a Structural Health Monitoring (SHM) system to automatically identify dam... more ABSTRACT The ability of a Structural Health Monitoring (SHM) system to automatically identify damage in a composite structure is a vital requirement demanded by end-users of such systems. This paper presents the demonstration of a potential method. A composite fatigue specimen was manufactured and initially tested at 1Hz for 1000 cycles. Acoustic emission (AE) signals were recorded for complete fatigue cycles periodically in order to establish a base-line associated with undamaged specimens. The specimen was then subjected to impact damage to create barely-visible impact damage (BVID) and subjected to further fatigue cycles with acoustic emission recorded until failure. The data was subsequently analysed using a range of techniques including basic RMS signal levels and frequency-based analysis. At various stages during the test, C-scanning was used to validate the results obtained. Results demonstrated that AE is capable of detecting BVID in composite materials under fatigue loading. The proposed method has wide applicability to composite structures which are subjected to cyclic loading, such as wind turbine blades.

Research paper thumbnail of Use of Macro Fibre Composite Transducers as Acoustic Emission Sensors

Remote Sensing, 2009

The need for ever lighter and more efficient aerospace structures and components has led to conti... more The need for ever lighter and more efficient aerospace structures and components has led to continuous optimization pushing the limits of structural performance. In order to ensure continued safe operation during long term service it is desirable to develop a structural health monitoring (SHM) system. Acoustic emission (AE) offers great potential for real time global monitoring of aerospace structures, however currently available commercial sensors have limitations in size, weight and adaptability to complex structures. This work investigates the potential use of macro-fibre composite (MFC) film transducers as AE sensors. Due to the inhomogeneous make-up of MFC transducers their directional dependency was examined and found to have limited effect on signal feature data. However, signal cross-correlations revealed a strong directional dependency. The sensitivity and signal attenuation with distance of MFC sensors were compared with those of commercially available sensors. Although noticeably less sensitive than the commercial sensors, the MFC sensors still had an acceptable operating range. Furthermore, a series of compressive carbon fiber coupon tests were monitored in parallel using both an MFC sensor and a commercially available sensor for comparison. The results showed good agreement of AE trends recorded by both sensors.

Research paper thumbnail of An autonomous structural health monitoring solution

Smart Sensors, Actuators, and MEMS VI, 2013

ABSTRACT Combining advanced sensor technologies, with optimised data acquisition and diagnostic a... more ABSTRACT Combining advanced sensor technologies, with optimised data acquisition and diagnostic and prognostic capability, structural health monitoring (SHM) systems provide real-time assessment of the integrity of bridges, buildings, aircraft, wind turbines, oil pipelines and ships, leading to improved safety and reliability and reduced inspection and maintenance costs. The implementation of power harvesting, using energy scavenged from ambient sources such as thermal gradients and sources of vibration in conjunction with wireless transmission enables truly autonomous systems, reducing the need for batteries and associated maintenance in often inaccessible locations, alongside bulky and expensive wiring looms. The design and implementation of such a system however presents numerous challenges. A suitable energy source or multiple sources capable of meeting the power requirements of the system, over the entire monitoring period, in a location close to the sensor must be identified. Efficient power management techniques must be used to condition the power and deliver it, as required, to enable appropriate measurements to be taken. Energy storage may be necessary, to match a continuously changing supply and demand for a range of different monitoring states including sleep, record and transmit. An appropriate monitoring technique, capable of detecting, locating and characterising damage and delivering reliable information, whilst minimising power consumption, must be selected. Finally a wireless protocol capable of transmitting the levels of information generated at the rate needed in the required operating environment must be chosen. This paper considers solutions to some of these challenges, and in particular examines SHM in the context of the aircraft environment.

Research paper thumbnail of Structural health monitoring of buckling composite structures using acoustic emission

Research paper thumbnail of On the Development of a Damage Detection System using Macro-fibre Composite Sensors

Journal of Physics: Conference Series, 2012

Macro-fibre composite (MFC) sensors, originally developed as actuators by NASA, have been investi... more Macro-fibre composite (MFC) sensors, originally developed as actuators by NASA, have been investigated for three components of a damage detection system for composite structures; actuation, sensing and energy harvesting. MFC sensors are constructed from piezoelectric fibres embedded in an epoxy matrix and offer greater flexibility than traditional sensors for embedding due to their low profile and low weight. It is

Research paper thumbnail of Damage classification in carbon fibre composites using acoustic emission: A comparison of three techniques

Composites Part B: Engineering, 2015

Classifying the type of damage occurring within a structure using a structural health monitoring ... more Classifying the type of damage occurring within a structure using a structural health monitoring system can allow the end user to assess what kind of repairs, if any, that a component requires. This paper investigates the use of acoustic emission (AE) to locate and classify the type of damage occurring in a composite, carbon fibre panel during buckling. The damage was first located using a bespoke location algorithm developed at Cardiff University, called delta-T mapping. Signals identified as coming from the regions of damage were then analysed using three AE classification techniques; Artificial Neural Network (ANN) analysis, Unsupervised Waveform Clustering (UWC) and corrected Measured Amplitude Ratio (MAR). A comparison of results yielded by these techniques shows a strong agreement regarding the nature of the damage present in the panel, with the signals assigned to two different damage mechanisms, believed to be delamination and matrix cracking. Ultrasonic C-scan images and a digital image correlation (DIC) analysis of the buckled panel were used as validation. MAR's ability to reveal the orientation of recorded signals greatly assisted the identification of the delamination region, however, ANN and UWC have the ability to group signals into several different classes, which would prove useful in instances where several damage mechanisms were generated. Combining each technique's individual merits in a multi-technique analysis dramatically improved the reliability of the AE investigation and it is thought that this cross-correlation between techniques will also be the key to developing a reliable SHM system.

Research paper thumbnail of Structural Health Monitoring of Composite Structures Using Embedded Transducers

Research paper thumbnail of ACOUSTIC EMISSION MONITORING OF BUCKLING BEHAVIOUR IN IMPACT-DAMAGED COMPOSITE PLATES

Research paper thumbnail of Buckling and Postbuckling of Impact Damaged Composite Plates

This paper describes tests to examine the buckling behaviour of a carbon fibre panel subject to d... more This paper describes tests to examine the buckling behaviour of a carbon fibre panel subject to damage via an impact load, simply supported along all four edges and loaded in uniaxial compression. The buckling shape was monitored using a geometrical Moiré fringe technique and these experimental results were compared with a finite element model. The correlation between the experimental results and the model was very good and provided confirmation of the relevance of the geometric monitoring technique for observing the buckling behaviour of such panels. The test was also continuously monitored using resonant acoustic emission (AE) sensors mounted directly on the composite panel. AE parametric data was recorded together with waveforms for events above 60dB. Time-of-arrival methods were used to locate the sources of events in the panel. The results of the AE monitoring indicated that no further damage due to delamination was induced in the panel as a result of this test. Subsequent ultrasonic scanning of the panel confirmed this finding. The AE results also indicated sources of acoustic emission that corresponded with bending in the panel and it is postulated that AE is a useful technique for identification of bending in panels, allowing buckling modes to be identified and monitored.

Research paper thumbnail of An Investigation of Frequency as an Acoustic Emission Signal Discriminator in Carbon Fibre Composite Materials

This work considers the use of frequency content as a discriminating factor for AE signals from c... more This work considers the use of frequency content as a discriminating factor for AE signals from carbon fibre composites. An artificial AE source generated by a conical transducer was used to investigate the effects of specimen geometry and sensor response on the frequency content of recorded signals. Additionally, AE signals were recorded from different damage mechanisms in tensile and beam buckling coupon specimens. The peak frequency content was used to examine signals resulting from the different damage modes observed and observations were in general agreement with previous research studies. However, it was shown that great care is required when using peak frequency content as a discriminating factor because geometry and sensor response have a significant effect on the frequency content of a recorded signal.

Research paper thumbnail of AE WAVE PROPAGATION AND NOVEL SOURCE LOCATION IN COMPOSITE PLATES

Source location in carbon-fibre composite structures is very complex because the wave velocity is... more Source location in carbon-fibre composite structures is very complex because the wave velocity is dependent on the direction of propagation relative to the fibre lay-up. The problem is further complicated by signal attenuation and dispersion. This paper reports on an investigation into signal propagation and source location in carbon-fibre composite plates.

Research paper thumbnail of Imperfection Sensitivity In Plates -An Assessment Using DIC

This paper examines the effect of imperfections on the behaviour of a series of panels, simply su... more This paper examines the effect of imperfections on the behaviour of a series of panels, simply supported along all four edges, and subject to compressive in-plane loading. In each case Digital Image Correlation (DIC) is used to determine the initial profile and set-up of the structure and to monitor its behaviour during test. The data is used to automatically generate a series of meshes representative of each of these specimens, suitable for analysis using Finite Element Analysis. Comparison of the results obtained from these analyses with those found during the experiments modelled shows an improved correlation when compared with standard techniques for assessing imperfection sensitivity. Set-up is straightforward and models can be obtained quickly based on the data collected.

Research paper thumbnail of Free vibration analysis of beams and frames with multiple cracks for damage detection

Journal of Sound and Vibration, 2014

ABSTRACT The problem of calculating the natural frequencies of beams with multiple cracks and fra... more ABSTRACT The problem of calculating the natural frequencies of beams with multiple cracks and frames with cracked beams is studied. The natural frequencies are obtained using a new method in which a rotational spring model is used to represent the cracks. For beams, dynamic stiffness matrices of order 4 are obtained in a recursive manner, according to the number of cracks, by applying partial Gaussian elimination. The Wittrick–Williams algorithm is used to compute the natural frequencies in the resulting transcendental eigenvalue problem. Published numerical examples for cracked beams are used for validation. The global dynamic stiffness matrix of a frame with multiply cracked members is then assembled. A published two bay frame example is used to evaluate the new method. The effect of changing the location of a crack in a two bay two storey frame is studied numerically, giving insight into the inverse problem of damage detection.

Research paper thumbnail of Detection and Location of Impact Damage using Acoustic Emission

Impact damage is one of the greatest weaknesses of composite materials and efforts taken to impro... more Impact damage is one of the greatest weaknesses of composite materials and efforts taken to improve its understanding, analysis and prevention have slowed the introduction of composite materials to large-scale and safety critical structures. In order to make this step, operators must be able to ensure the structural integrity and safe operation of composite structures during long service lives. One such approach to this is the use of Structural Health Monitoring (SHM) to continuously monitor the condition of a structure. In this paper a novel mapping based acoustic emission (AE) source location technique is used to detect and locate impact events on a carbon fibre composite panel.

Research paper thumbnail of Approaches to acoustic emission monitoring with applicability to key components in wind turbines

Research paper thumbnail of Towards the development of lightweight structural health monitoring systems for aerospace applications

Research paper thumbnail of Rapid text referral

A 23-year-old soldier developed a facial ulcer after returning from Belize. The possibility of cu... more A 23-year-old soldier developed a facial ulcer after returning from Belize. The possibility of cutaneous leishmaniasis prompted referral to our unit. The lesion was photographed with a mobile phone and texted to a secure webpage with password access (fi gure). The images supported the diagnosis of cutaneous leishmaniasis and the patient was admitted. The diagnosis was confi rmed histologically and the parasites found to be Leishmania braziliensis. The patient was treated as an inpatient with a standard regimen of 20 mg/kg of intravenous sodium stibogluconate for 20 days. This therapy led to an uneventful recovery, with no relapse at 6 months follow-up.

Research paper thumbnail of Thermoelectric energy harvesting for wireless sensor systems in aircraft

Research paper thumbnail of Harvesting vibration energy for structural health monitoring in aircraft

... Test-Rig. The panel was tested using the rig shown in Fig. 2a. ... The frame had a mass of ap... more ... Test-Rig. The panel was tested using the rig shown in Fig. 2a. ... The frame had a mass of approximately 22kg in order to prevent the loss of vibration energy by the displacement of the frame. Fig. 2 Test Rig a) frame with panel mounted b) position of energy harvesting devices ...

Research paper thumbnail of Modelling the effects of geometric imperfections on the buckling and initial post-buckling behaviour of flat plates under compression using measured data

ABSTRACT Recent developments in optical techniques have allowed accurate representations of the... more ABSTRACT Recent developments in optical techniques have allowed accurate representations of the geometry of test specimens to be obtained. These enable the nature of geometric imperfections resulting from manufacture or set-up to be captured in a form which allows them to be incorporated directly into models generated to predict the behaviour of the structure. This study examines the effect of such imperfections on the behaviour of a series of panels, simply supported along all four edges, and subject to uniaxial compressive in-plane loading. In each case, digital image correlation is used to determine the initial profile and set-up of the panel and to monitor its behaviour during test. The data are used to automatically generate a series of meshes representative of each of the specimens tested, suitable for finite element analysis. Comparison of the results obtained from these analyses with those found during the experiments modelled shows an improved correlation when compared with standard techniques for assessing imperfection sensitivity. Set-up is straightforward, and models can be obtained quickly based on the data collected.

Research paper thumbnail of Automated Damage Detection in Composite Components Using Acoustic Emission

Key Engineering Materials, 2013

ABSTRACT The ability of a Structural Health Monitoring (SHM) system to automatically identify dam... more ABSTRACT The ability of a Structural Health Monitoring (SHM) system to automatically identify damage in a composite structure is a vital requirement demanded by end-users of such systems. This paper presents the demonstration of a potential method. A composite fatigue specimen was manufactured and initially tested at 1Hz for 1000 cycles. Acoustic emission (AE) signals were recorded for complete fatigue cycles periodically in order to establish a base-line associated with undamaged specimens. The specimen was then subjected to impact damage to create barely-visible impact damage (BVID) and subjected to further fatigue cycles with acoustic emission recorded until failure. The data was subsequently analysed using a range of techniques including basic RMS signal levels and frequency-based analysis. At various stages during the test, C-scanning was used to validate the results obtained. Results demonstrated that AE is capable of detecting BVID in composite materials under fatigue loading. The proposed method has wide applicability to composite structures which are subjected to cyclic loading, such as wind turbine blades.

Research paper thumbnail of Use of Macro Fibre Composite Transducers as Acoustic Emission Sensors

Remote Sensing, 2009

The need for ever lighter and more efficient aerospace structures and components has led to conti... more The need for ever lighter and more efficient aerospace structures and components has led to continuous optimization pushing the limits of structural performance. In order to ensure continued safe operation during long term service it is desirable to develop a structural health monitoring (SHM) system. Acoustic emission (AE) offers great potential for real time global monitoring of aerospace structures, however currently available commercial sensors have limitations in size, weight and adaptability to complex structures. This work investigates the potential use of macro-fibre composite (MFC) film transducers as AE sensors. Due to the inhomogeneous make-up of MFC transducers their directional dependency was examined and found to have limited effect on signal feature data. However, signal cross-correlations revealed a strong directional dependency. The sensitivity and signal attenuation with distance of MFC sensors were compared with those of commercially available sensors. Although noticeably less sensitive than the commercial sensors, the MFC sensors still had an acceptable operating range. Furthermore, a series of compressive carbon fiber coupon tests were monitored in parallel using both an MFC sensor and a commercially available sensor for comparison. The results showed good agreement of AE trends recorded by both sensors.

Research paper thumbnail of An autonomous structural health monitoring solution

Smart Sensors, Actuators, and MEMS VI, 2013

ABSTRACT Combining advanced sensor technologies, with optimised data acquisition and diagnostic a... more ABSTRACT Combining advanced sensor technologies, with optimised data acquisition and diagnostic and prognostic capability, structural health monitoring (SHM) systems provide real-time assessment of the integrity of bridges, buildings, aircraft, wind turbines, oil pipelines and ships, leading to improved safety and reliability and reduced inspection and maintenance costs. The implementation of power harvesting, using energy scavenged from ambient sources such as thermal gradients and sources of vibration in conjunction with wireless transmission enables truly autonomous systems, reducing the need for batteries and associated maintenance in often inaccessible locations, alongside bulky and expensive wiring looms. The design and implementation of such a system however presents numerous challenges. A suitable energy source or multiple sources capable of meeting the power requirements of the system, over the entire monitoring period, in a location close to the sensor must be identified. Efficient power management techniques must be used to condition the power and deliver it, as required, to enable appropriate measurements to be taken. Energy storage may be necessary, to match a continuously changing supply and demand for a range of different monitoring states including sleep, record and transmit. An appropriate monitoring technique, capable of detecting, locating and characterising damage and delivering reliable information, whilst minimising power consumption, must be selected. Finally a wireless protocol capable of transmitting the levels of information generated at the rate needed in the required operating environment must be chosen. This paper considers solutions to some of these challenges, and in particular examines SHM in the context of the aircraft environment.

Research paper thumbnail of Structural health monitoring of buckling composite structures using acoustic emission

Research paper thumbnail of On the Development of a Damage Detection System using Macro-fibre Composite Sensors

Journal of Physics: Conference Series, 2012

Macro-fibre composite (MFC) sensors, originally developed as actuators by NASA, have been investi... more Macro-fibre composite (MFC) sensors, originally developed as actuators by NASA, have been investigated for three components of a damage detection system for composite structures; actuation, sensing and energy harvesting. MFC sensors are constructed from piezoelectric fibres embedded in an epoxy matrix and offer greater flexibility than traditional sensors for embedding due to their low profile and low weight. It is