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Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006475
EISBN: 978-1-62708-190-0
... Abstract Electromagnetic signals at microwave and millimeter-wave frequencies are well suited for inspecting dielectric materials and composite structures in many critical applications. This article presents a partial list of reported nondestructive testing (NDT) application areas...
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
... Electromagnetic signals from the laser weld process Imaging the weld after the keyhole (x-ray or other means) An excellent review of sensor technology for weld quality monitoring can be found in Ref 17 . Acoustic Monitoring Acoustic diagnostics is based on the premise that the behavior of good...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003234
EISBN: 978-1-62708-199-3
... serviceability can cause instrument signals that mask critical variables or are mistakenly interpreted to be caused by critical variables. Eddy-Current vs. Magnetic Inspection Methods In eddy-current inspection, eddy currents create their own electromagnetic field, which is sensed either through...
Image
Published: 01 August 2018
Fig. 8 (a) Focused electromagnetic acoustic transducer design using single generator and three coils as detectors. (b) Detected signal amplitudes on each detector with respect to angle of defect. Note that the color scales are normalized for each plot. Source: Ref 38 More
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006458
EISBN: 978-1-62708-190-0
... Abstract This article describes the basic features of electromagnetic acoustic transducers (EMATs) and discusses their existing and some potential uses within the field of ultrasonic nondestructive evaluation (UNDE). It provides sufficient basic and practical information to make an informed...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006450
EISBN: 978-1-62708-190-0
... serviceability may cause instrument signals that mask critical variables or are mistakenly interpreted to be caused by critical variables. Eddy Current versus Magnetic Inspection Methods In eddy-current inspection, the eddy currents create their own electromagnetic field, which can be sensed either...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003237
EISBN: 978-1-62708-199-3
... preamplifier and then to the main signal-processing equipment. The preamplifier can be miniaturized and housed inside the sensor enclosure, facilitating setup and reducing vulnerability to electromagnetic noise. Fig. 1 Typical construction of an acoustic-emission resonant sensor During an AE test...
Image
Published: 01 August 2018
Fig. 16 Schematic representation of pulse-echo (PE) (upper image) and pitch-catch (PC) (lower image) electromagnetic acoustic transducer (EMAT) systems. Normally, separate T- and R-coils are used even for the PE configuration; in this case, a thin strip or wire R-coil (less than a skin depth More
Book Chapter

Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003235
EISBN: 978-1-62708-199-3
... decay with respect to the distance traveled. Microwave Detection of Surface Cracks in Metals When an electromagnetic wave is incident on a metallic surface that has slits or cracks, the metallic surface reradiates (reflects) a signal because of induced current. Under the proper conditions...
Book Chapter

Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003233
EISBN: 978-1-62708-199-3
... the flux density typical of the leakage field from a slot and corresponding signal search as in Fig. 3 . Fig. 3 Flux leakage measurement using a search coil Fig. 4 Leakage flux and search coil signal as a function of position While an inductive coil measures flux gradient, a Hall...
Series: ASM Handbook Archive
Volume: 10
Publisher: ASM International
Published: 01 January 1986
DOI: 10.31399/asm.hb.v10.a0005692
EISBN: 978-1-62708-178-8
... for photography is to refract light differently as a function of principles. optical density. wavelength is minimized. See also achro- matic, apochromatic lens. analytical curve. The graphical representa- absorption (of electromagnetic radiation). A tion of a relation between (1) the intensity decrease...
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: 4C
Publisher: ASM International
Published: 09 June 2014
DOI: 10.31399/asm.hb.v04c.a0005857
EISBN: 978-1-62708-167-2
... of this demagnetization current is connected to the coercive force of the material. A coercimeter with two attached electromagnets, with a second situated inside the first, was devised. The intensity of the demagnetizing current with zero signal of the inner transducer contains information on the properties...
Series: ASM Handbook
Volume: 13A
Publisher: ASM International
Published: 01 January 2003
DOI: 10.31399/asm.hb.v13a.a0003658
EISBN: 978-1-62708-182-5
... detection is based on the physics of the way in which microwaves interact with the materials of the coating and the sublayers of corrosion. Paint, appliqués, and corrosion byproducts are all dielectric materials, and each influences a microwave signal differently. In addition, the damage caused by corrosion...
Series: ASM Handbook
Volume: 4C
Publisher: ASM International
Published: 09 June 2014
DOI: 10.31399/asm.hb.v04c.a0005853
EISBN: 978-1-62708-167-2
... line and have a good earth ground. None of the signal cables should be run in the same conduit as power cables or relay outputs. A separate conduit must be used for any signal cable. If the sensor is close to the induction coil and there is electromagnetic interference, the sensor may be moved...
Series: ASM Handbook
Volume: 14B
Publisher: ASM International
Published: 01 January 2006
DOI: 10.31399/asm.hb.v14b.a0009152
EISBN: 978-1-62708-186-3
... to an alarm that gives a signal when this peak force exceeds the preset limit. In other cases, the complete force signature is monitored and displayed, providing additional information to the operator. Force sensors can help to achieve the following objectives ( Ref 2 ): Protection of machine from...
Series: ASM Handbook
Volume: 10
Publisher: ASM International
Published: 15 December 2019
DOI: 10.31399/asm.hb.v10.a0006748
EISBN: 978-1-62708-213-6
... in the trans- density. analysis based on the detection of character- mission electron microscope equipped to istic radionuclides following nuclear bom- detect and quantify many different signals absorption (of electromagnetic radiation). A bardment. See also neutron activation from the specimen. The technique...
Series: ASM Handbook
Volume: 4C
Publisher: ASM International
Published: 09 June 2014
DOI: 10.31399/asm.hb.v04c.a0005858
EISBN: 978-1-62708-167-2
.... Electromagnetic Fields Present in the Environment Radar Radars are used for navigation, weather forecasting, numerous military applications, and various other functions. They emit pulsed microwave signals. The peak power of these electromagnetic pulses can be high even though the average power is low...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006467
EISBN: 978-1-62708-190-0
.... 18 Plot of eddy-current signal output versus flaw depth to measure detectability of flaws in high-tensile sheared bolts. Source: Ref 1 Electromagnetic Systems Electromagnetic systems include the systems that use magnetic fields generated by alternating current flowing in a solenoid...
Series: ASM Handbook
Volume: 17
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.hb.v17.a0006438
EISBN: 978-1-62708-190-0
... of the test component. Typical inspection techniques examine some metric or signal against a threshold level. The signal may be a simple voltage or indicator level or it may be a complex multidimensional image; however, the basic concept of flaw detection is that the signal exceeds a detection threshold...