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signal-processing method

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Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006464
EISBN: 978-1-62708-190-0
... surface. This article discusses the strategies for implementing thermography for NDE, including the steady-state/whole-body approach and transient heat conduction. It describes the most common signal-processing methods, such as thermographic signal reconstruction, lock-in thermography, and pulsed-phase...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003237
EISBN: 978-1-62708-199-3
... type. Relationship to Other Test Methods Acoustic emission (AE) differs from most other nondestructive testing (NDT) methods in two key respects. First, the signal has its origin in the material itself, not in an external source. Second, acoustic emission detects movement, while most other...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006476
EISBN: 978-1-62708-190-0
... and applied, along with microstructural variations such as hardness and carbon content. When measuring MBN using the traditional method, the sample is magnetized with an alternating magnetic field (typically 125 Hz), and the signal containing Barkhausen noise is amplified and filtered in a frequency range...
Series: ASM Handbook
Volume: 18
Publisher: ASM International
Published: 31 December 2017
DOI: 10.31399/asm.hb.v18.a0006368
EISBN: 978-1-62708-192-4
... in time, frequency, and time-frequency domains. Signal Processing Vast implementation of signal-processing techniques is due to the fast development in electronics and computers today (2017). Powerful digital signal-processing methods are currently used for data analyses in various fields...
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006936
EISBN: 978-1-62708-395-9
... plot, as shown in the upper right-hand corner of Fig. 17 , in which each event represents one pixel on the display. The form of the histogram is greatly influenced by the way the ultrasonic waveform is analyzed. Therefore, prior knowledge about the signal processing methods must accompany both...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006443
EISBN: 978-1-62708-190-0
... be judiciously examined to determine suitability for new applications. Quantification of the performance level, calibration (or process control) methods, and acceptance criteria is particularly important in extrapolating the applicability of prior NDE data to a new NDE engineering problem. Conversely...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006453
EISBN: 978-1-62708-190-0
... and selective excitation configuration of the signal-generation mechanisms in thermal nondestructive evaluation methods. The three widely used approaches to TNDE are surface-excited thermography, vibrothermography, and thermoelastic stress analysis. The article provides information on the common features...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005638
EISBN: 978-1-62708-174-0
... documentation. To be beneficial to production, a high degree of confidence must be statistically established to minimize the occurrence of both false positives and false negatives. Sensors The reliability of various signals generated by the laser weld process requires statistical process control methods...
Series: ASM Handbook
Volume: 21
Publisher: ASM International
Published: 01 January 2001
DOI: 10.31399/asm.hb.v21.a0003436
EISBN: 978-1-62708-195-5
...-transmission (TT) ultrasonics and pulse-echo (PE) ultrasonics. The TT method uses two transducers, one on each side of the part, to measure the acoustic attenuation through the structure. One transducer is the transmitter and is electronically pulsed to produce an ultrasonic signal, and the other transducer...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006634
EISBN: 978-1-62708-213-6
... and subsequently analyzing the uncertainty from both the calibration process and the measurement process. This article briefly summarizes the most common calibration and uncertainty analysis methods, namely external standard methods, abbreviated external standard methods, internal normalization, internal standard...
Series: ASM Handbook
Volume: 6
Publisher: ASM International
Published: 01 January 1993
DOI: 10.31399/asm.hb.v06.a0001473
EISBN: 978-1-62708-173-3
... method of detecting leaks in storage tanks. By taking triangulation measurements from points around the tank, the source can be located. Perhaps the most effective use of AE is in the proof testing of pressure vessels. The AE process was originally developed for use with pressure tests of vessels...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005616
EISBN: 978-1-62708-174-0
... surface area with one pass, which helps minimize the lift-off variations. Considering the noise source in the eddy current method, having a small variation in the lift-off is a big advantage over many single-probe-based scan techniques. In many cases, advanced signal processing algorithms can be used...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006477
EISBN: 978-1-62708-190-0
... the noise source in the eddy-current method, having a small variation in the lift-off is a big advantage over many single-probe-based scan techniques. In many cases, advanced signal-processing algorithms can be used to produce more intuitive and easy-to-interpret test results when compared to conventional...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006478
EISBN: 978-1-62708-190-0
...-transmission (TT) ultrasonics and pulse-echo (PE) ultrasonics. The TT method uses two transducers, one on each side of the part, to measure the acoustic attenuation through the structure. One transducer is the transmitter and is electronically pulsed to produce an ultrasonic signal, and the other transducer...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006454
EISBN: 978-1-62708-190-0
... of stress waves by sudden movement in stressed materials. Classic sources of AE are defect-related deformation processes such as crack growth and plastic deformation. The principle of the AE test method is illustrated in Fig. 1 . Sudden movement at the source produces a stress wave, which radiates out...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.9781627081900
EISBN: 978-1-62708-190-0
Series: ASM Handbook
Volume: 1A
Publisher: ASM International
Published: 31 August 2017
DOI: 10.31399/asm.hb.v01a.a0006336
EISBN: 978-1-62708-179-5
..., technical society, or commercial specifications. These methods can also be used for process/feedback control or statistical quality design and control as well as accept/reject quality control. To select the most efficient NDI method, one must identify the shape/size/location of the anomaly or material...
Book Chapter

By D.R. Crow
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0001741
EISBN: 978-1-62708-178-8
... circumstances, controlled convection, particularly as rapidly rotated electrodes, is used to enhance current signals. For most circumstances, the current-voltage curves for metal ions in solution may be interpreted in terms of the interplay of the diffusion process, by which they arrive at the surface...
Series: ASM Handbook
Volume: 24A
Publisher: ASM International
Published: 30 June 2023
DOI: 10.31399/asm.hb.v24A.a0006982
EISBN: 978-1-62708-439-0
... is placed in contact with the sample to test and is connected to the controller. Fig. 2 Principle of ultrasonic testing. (a) Ultrasonic probe faces a sample to inspect that contains a flaw. (b) Plot of signal obtained by the inspection As stated, UT processes can be performed manually...
Series: ASM Handbook
Volume: 14B
Publisher: ASM International
Published: 01 January 2006
DOI: 10.31399/asm.hb.v14b.a0005153
EISBN: 978-1-62708-186-3
... manufacturing processes. Basic Concepts of Control Systems A signal is defined as a representation (typically mechanical or electrical) of a physical condition, and a system is a physical entity with input and output signals. Control systems are used to drive the output signals of the system...