Test method electromagnetic

EDDY CURRENT TESTING - An electromagnetic nondestructive testing method in which eddy-current flow is induced in the test object. Changes in flow caused by variations in the object are deflected into a nearby coil or coils where they are measured. 

ASTM D 7113/D 7113M. 2010. Standard test method for density of bituminous paving mixtures in place by the electromagnetic surface contact methods. West Conshohocken, PA ASTM International. 

Optical test methods use the visible part of the electromagnetic spectrum ie, they comprise a subset of the electromagnetic test methods. 

Many polymers and most PMC show no or only comparatively low electrical conductivity, which limits application of electromagnetic test methods. One of the main exceptions is CFRP. The continuous network of carbon fibers in CFRP allows for electrical resistance measurements, eg, based on the four-probe method. Electrical potential (101) or resistance methods are used in fracture mechanics to detect delaminations (102) and to monitor damage in CFRP (103). Whether the application of electrodes is nondestructive depends on the intended use. 

E 376-89 Practice for Measuring Coating Thickness by Magnetic-field or Eddy-Current (Electromagnetic) Test Methods... 

The electromagnetic shielding effectiveness of a nickel-graphite filled silicone gasket with and without an EMI adhesive, measured over a wide frequency range, is shown in Fig. 5.20.1 1 Test methods and requirements for the control of EMI may be found in MIL-STD-461.t ... 

ANSI/RESNA WC/Vol. 2-19983, Section 21, Reqnirements and test methods for electromagnetic compatibility of powered wheelchairs and motorized scooters... 

JIS C 8825 Testing methods for EMC of smaU polymer electrolyte fuel cell power systems (electromagnetic compatibility) Japan)... 

ISO 11452 Road vehicles—component test methods for electrical distuibances from narrowband radiated electromagnetic energy... 

Libby, H.L. Introduction to Electromagnetic Nondestructive Test Methods, John Wiley Sons, New York ( 1971). 

Many of the methods used to study the fibre content and distribution were developed for steel fibre reinforcement. I n this case, the electromagnetic properties of the fibres can be used to develop test methods based on electrical measurement, such as that previously mentioned (Section 6.2.2) of Uomoto and Kobayashi [8]. I n the course of their studies, they also found that the i nduced current is sensitive to fibre orientation, and there is thus the potential for developing a method to detect the extent of the anisotropy. 

B. Malmberg and A. Skarendahl, Determination of fibre content, distribution and orientation in steel fibre concrete by electromagnetic technique , in R.N. Swamy (ed.) Testing and Test Methods of Fibre Cement Composites, Proc. RILEM Symp., The Construction Press, UK, 1978, pp. 289-296. 

This paper compares experimental data for aluminium and steel specimens with two methods of solving the forward problem in the thin-skin regime. The first approach is a 3D Finite Element / Boundary Integral Element method (TRIFOU) developed by EDF/RD Division (France). The second approach is specialised for the treatment of surface cracks in the thin-skin regime developed by the University of Surrey (England). In the thin-skin regime, the electromagnetic skin-depth is small compared with the depth of the crack. Such conditions are common in tests on steels and sometimes on aluminium. 

In this work, a microwave interferometric method and apparatus for vibration measurements is described. The principle of operation is based on measurement of the phase of reflected electromagnetic wave changing due to vibration. The most important features of the method are as follows simultaneous measurement of tlie magnitude and frequency of the rotating object high measurement accuracy weak influence of the roll diameter, shape and distance to the object under test. Besides, tlie reflecting surface can be either metallic or non-metallic. Some technical characteristics are given. 

Shear Horizontal (SH) waves generated by Electromagnetic Acoustic Transducer (EMAT) have been used for sizing fatigue cracks and machined notches in steels by Time-of-Flight Diffraction (TOED) method. The used EMATs have been Phased Array-Probes and have been operated by State-of-the-art PC based phased array systems. Test and system parameters have been optimised to maximise defect detection and signal processing methods have been applied to improve accuracy in the transit time measurements. 

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