Magnetoelastic transducer for determining mechanical stresses in ferromagnetic materials

The invention relates to instrument engineering, control ierazrushayuschemu materials technical diagnostics and can be used as probes to determine overhead mechanical stresses in ferromagnetic materials to estimate resource consumption device units operating under load.

The closest to the claimed technical result is the decision of the magnetoelastic sensor for detecting mechanical stress [patent №2073856, cl. G01N 27/80, publ. 20.02.1997], which comprises a housing mounted therein mandrel placed on it with excitation and measurement coils, in this case it is provided with two additional cores strip form and are respectively arranged at two measuring coils and the main core is H-shaped, and additional cores are mounted symmetrically between the poles of the main central portion thereof.

The disadvantages of the known sensors are relatively large, which does not allow to conduct measurements of the mechanical tension in the local points, highlight the complexity of Barkhausen jumps, as the winding cores may strip guidance electrodynamic forces (EMF) with the frequency of the excitation and weak immunity from outsiders EMF.

The technical result of the invention is to improve noise immunity and sensitivity.

This technical result is achieved in that the magnetoelastic sensor to determine the mechanical stresses in ferromagnetic materials includes a housing mounted in it core in U-shape with placed on it exciting and controlling the level of excitation coils, as well as an additional core is U-shaped, which is available measuring coil, wherein the additional core mounted symmetrically between the poles of the main core so that its plane is perpendicular to the plane of the main core. Magnetoelastic sensor housing is made of conductive magnetic material, and acting as a screen against external interference. The plane of the core with the measuring coil is perpendicular to the main plane of the core, and therefore, it is practically not induced EMF at the excitation frequency, and the EMF of the Barkhausen jumps when it remains practically unchanged.

A magnetoelastic sensor for detecting mechanical stress in the ferromagnetic material consists of a housing 1, two U-shaped magnetic cores 2 and 3, the magnetic circuit 3 is set in the interpolar space of the yoke 2 perpendicular to it. In the center of the magnetic core 2 is wound magnetizing winding 4, closer to the poles of the magnetic circuit wound two series-connected winding 5 for controlling the excitation level. 3 wound on magnetic measuring coil 6 for measuring the magnetic noise generated by the Barkhausen jumps in the magnetization reversal of the controlled area.

Magnetoelastic sensor operates as follows. Impose sensor PA-controlled surface, which is under mechanical pressure. By passing an alternating current frequency of 20-30 Hz of the field winding, produces a controlled surface magnetization alternating electromagnetic zero. At the signal output level control winding excitation provides the required value of the electromagnetic field of the magnetization, which is then kept constant during the measurement. According to RMS value of the magnetic noise, or by the number of Barkhausen jumps determined by measuring the output of the measuring coil, judge the value of the mechanical stress. To determine the absolute value of the strain using the calibration curve obtained with standard samples with known mechanical stresses.