Classification of ultrasonic signals
In ultrasonic non-destructive testing it is very difficult to detect flaws in materials with coarse-grain structure. The ultrasonic signals measured on these materials contain echoes which are very similar to fault echoes. These echoes arise from grains which are contained in the material. For the detection of flaws various methods for suppressing echoes from grains have to be used. In this work we used the method for filtering ultrasonic signals based on discrete wavelet transform. For the classification of ultrasonic signals in A-scan we used a pattern recognition method called support vector machines. In this study we classify signals with fault echoes, echo from weld and back-wall echo. Ultrasonic signals were measured on materials used for constructing aeroplane engines. The experimental results indicate the performance of the proposed approach.
Design and Implementation of Water Depth Measurement and Object Detection Model Using Ultrasonic Signal System
There are several ways to measure water depth without physical contact. Some devices have infrared light emitters and receivers to determine water depth. Other devices have laser-based systems which have improved accuracy and precision. Presently, the detection techniques of laser, radar, infrared ray and ultrasonic have been widely applied at the aspect of water depth measurement. The research of the water depth measurement system backing up with high ratio of capability to low price has ended at Ultrasonic Range Finder. The difficulty in measuring water depth and object detection will no longer be a complicated issue. A simple technique to determine water depth and object detection is described in this paper. In this project it is employed sensors like ultrasonic transducer. A mechanical part in the device is introduced which is a salient part for the project to measure the water depth. Ultrasonic transducers are connected in this part. Angle is measured through this mechanical part therefore it can conveniently determine water depth and object. This technique has provided a useful tool to more accurately to identify the water depth and object. The purpose of this paper is to illustrate the noble methodology for measuring water depth and object detection using Ultrasonic sounds to provide efficient and effective way. This paper provides researchers a good understanding of Ultrasonic signal and its characteristics to measure the depth of the water and object detection.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.