4 research outputs found
An Opening Profile Recognition Method for Magnetic Flux Leakage Signals of Defect
The defect opening profile recognition is of great concern in the magnetic flux leakage (MFL) measurement technique. The detected spatial MFL signal has three components: horizontal, vertical, and normal components. Horizontal and normal component signals are commonly used to estimate the defect profile, while the vertical component has always been neglected. With the development of the high resolution and the 3-D MFL testing techniques, the vertical component signal is becoming more available. This paper analyzes the essential right-angle features of the vertical component signal, which is useful for the defect opening profile recognition. After obtaining the initial profile from the horizontal or normal component, the types of the right angle is identified from the vertical component, and the opening profile is further optimized based on these right-angle features. The opening profile recognition method is put forward in this paper to improve the accuracy of the recognition result of the defect. Both simulation and experimental tests are conducted to verify the good performance of the proposed method. Compared with the opening profiles recognized merely by the horizontal component signal, the proposed method shows better recognition results, which also validates that the vertical component signal can also be a useful information for the defect estimation
Investigation of wireless power transfer-based eddy current non-destructive testing and evaluation
PhD ThesisEddy current testing (ECT) is a non-contact inspection widely used as non-destructive
testing and evaluation (NDT&E) of pipeline and rail lines due to its high sensitivity to surface
and subsurface defects, cheap operating cost, tolerance to harsh environments, and capability
of a customisable probe for complex geometric surfaces. However, the remote field of
transmitter-receiver (Tx-Rx) ECT depends on the Tx-Rx coils gap, orientation, and lift-off
distance, despite each coil responding to the effect of sample parameters according to its liftoff distance. They bring challenges to accurate defect detection and characterisation by
weakening the ECT probe’s transfer response, affecting sensitivity to the defect, distorting the
amplitude of the extracted features, and responding with fewer feature points at non-efficient
energy transfer. Therefore, this study proposed a magnetically-coupled resonant wireless power
transfer (WPT)-based ECT (WPTECT) concept to build the relationship between Tx-Rx coil at
maximum energy transfer response, including shifting and splitting (resonance) frequency
behaviour.
The proposed WPTECT system was investigated in three different studies viz., (1)
investigated the multiple resonance point features for detection and characterisation of slots on
two different aluminium samples using a series-series (SS) topology of WPTECT; (2) mapped
and scanned pipeline with a natural dent defect using a flexible printed coil (FPC) array probe
based on the parallel-parallel (PP) topology of WPTECT; and (3) evaluated five different
WPTECT topologies for optimal response and extracted features and characterised entire
parameters of inclined angular Rolling Contact Fatigue (RCF) cracks in a rail-line material via
an optimised topology. Multiple feature extraction, selection, and fusion were evaluated for the
defect profile and compared in the study, unattainable by other ECT methods.
The first study's contribution investigated multiple resonances and principal component
analysis (PCA) features of the transfer response from scanning (eight) slots on two aluminium
samples. The results have shown the potential of the multiple features for slot depth and width
characterisation and demonstrated that the eddy-current density is highest at two points
proportionate to the slot width. The second study's contribution provided a larger area scanning
capability in a single probe amenable to complex geometrical structures like curvature surfaces.
Among the extracted individual and fused features for defect reconstruction, the multi-layer
feed-forward Deep learning-based multiple feature fusion has better 3D defect reconstruction,
whilst the second resonances feature provided better local information than the first one for
investigating pipeline dent area. The third study's contribution optimised WPTECT topology
for multiple feature points capability and its optimal features extraction at the desired lift-off
conditions. The PP and combined PP and SS (PS-PS) WPTECT topologies responded with
multiple resonances compared to the other three topologies, with single resonance, under the
same experimental situation. However, the extracted features from PS-PS topology provided
the lowest sensitivity to lift-off distances and reconstructed depth, width, and inclined angle of
RCF cracks with a maximum correlation, R2
-value of 96.4%, 93.1%, and 79.1%, respectively,
and root-mean-square-error of 0.05mm, 0.08mm, and 6.60
, respectively.
The demonstrated magnetically-coupled resonant WPTECT Tx-Rx probe characterised
defects in oil and gas pipelines and rail lines through multiple features for multiple parameters
information. Further work can investigate the phase of the transfer response as expected to offer
robust features for material characterisation. The WPTECT system can be miniaturised using
WPT IC chips as portable systems to characterise multiple layers parameters. It can further
evaluate the thickness and gap between two concentric conductive tubes; pressure tube
encircled by calandria tube in nuclear reactor fuel channels.PTDF Nigeri
Epidemiology of Injury in English Women's Super league Football: A Cohort Study
INTRODUCTION: The epidemiology of injury in male professional football has been well documented (Ekstrand, Hägglund, & Waldén, 2011) and used as a basis to understand injury trends for a number of years. The prevalence and incidence of injuries occurring in womens super league football is unknown. The aim of this study is to estimate the prevalence and incidence of injury in an English Super League Women’s Football squad. METHODS: Following ethical approval from Leeds Beckett University, players (n = 25) signed to a Women’s Super League Football club provided written informed consent to complete a self-administered injury survey. Measures of exposure, injury and performance over a 12-month period was gathered. Participants were classified as injured if they reported a football injury that required medical attention or withdrawal from participation for one day or more. Injuries were categorised as either traumatic or overuse and whether the injury was a new injury and/or re-injury of the same anatomical site RESULTS: 43 injuries, including re-injury were reported by the 25 participants providing a clinical incidence of 1.72 injuries per player. Total incidence of injury was 10.8/1000 h (95% CI: 7.5 to 14.03). Participants were at higher risk of injury during a match compared with training (32.4 (95% CI: 15.6 to 48.4) vs 8.0 (95% CI: 5.0 to 10.85)/1000 hours, p 28 days) of which there were three non-contact anterior cruciate ligament (ACL) injuries. The epidemiological incidence proportion was 0.80 (95% CI: 0.64 to 0.95) and the average probability that any player on this team will sustain at least one injury was 80.0% (95% CI: 64.3% to 95.6%) CONCLUSION: This is the first report capturing exposure and injury incidence by anatomical site from a cohort of English players and is comparable to that found in Europe (6.3/1000 h (95% CI 5.4 to 7.36) Larruskain et al 2017). The number of ACL injuries highlights a potential injury burden for a squad of this size. Multi-site prospective investigations into the incidence and prevalence of injury in women’s football are require