A detection of backside crack using rotational magnetic flux sensor with search coils

Abstract

We have developed a new magnetic Sensor Using a rotational magnetic field with a three-axis search coil for non-destructive testing(NDT). Using specimens with a machined crack in the center, we investigated the relationship between the position and the depth of a crack and the output signal of the three-axis search coil. The results of our experiments,.t;his sensor can clearly detect a crack existine on the revers e side of the sensine surface. In coil positioned orthogonal over the x-axis searchcoil. Each-=is search coil has 700 turns, The z-axis coil is a pamik"kpe Coil which outer radius is 1~" and thickness i s 1 " .It has 2oo-tums nXi& of 0 . 0 4~ Copper Wire. order to obtain large output signals, x-and y-axis search coils have an amorphous core( 1 x 7 x 7 m 3 ) . 0 " this paper, we present the construction, results of numerical analysis and experimental results of this sensor.

Non-destructive testing on stainless steel plate by rotational magnetic flux sensor

“…degree phase difkence. These exciting currents a~ adjusted by the PC so that the Lissajous's figure which is drawn by output signals ofthe x-and y-axis search coil become nearly a circle at the place of no de&ct [4]. Exciting currents are applied to two pairs of exciting coils.…”

A Deconvolution Approach to the Three Dimensional Identification of Cracks in Magnetic Slabs

“…In the past, several nondestructive crack detection techniques have been introduced (see, for example, [1][2][3][4][5]). Among those techniques, stray magnetic field monitoring, as a result of impressed current crack perturbation, has proven to be successful [6,7].…”

A State-of Art of Creative Sensor Devices Utilizing Magneto- Rheological Fluids

“…Magnetic flux sensors finds wide range of applications in magnetic anomaly detection technology, position tracking of human body movement, magnetic resonance imaging technology for medical / biological applications, detection of machined cracks and mechanical torque measurement [15][16][17][18][19][20]. Generally, there are two types of magnetic sensors, namely vector and scalar magnetometers based on the method used to measure the magnetic field.…”