A method and a device for non-invasive vibration-based condition monitoring of a machine placed on a physical frame of reference, using a time-domain broadband magnetoresistive sensor having a sensor transfer function of electric resistance versus magnetic field intensity, said machine comprising an attached magnet or a magnetic part; comprising the steps of: placing the magnetic sensor on said physical frame of reference at a distance from the machine and at a predetermined distance from the magnet or magnetic part, such that the magnetoresistive sensor is operating in a dynamic part of the sensor transfer function in respect of the magnetic field produced by the magnet or a magnetic part; capturing a time-domain magnetic field signal transduced by the sensor; and using an electronic data processor to process the captured signal to obtain a vibration-based indicator of the machine's condition.

A method and a device for non-invasive vibration-based condition monitoring of a machine placed on a physical frame of reference, using a time-domain broadband magnetoresistive sensor having a sensor transfer function of electric resistance versus magnetic field intensity, said machine comprising an attached magnet or a magnetic part; comprising the steps of: placing the magnetic sensor on said physical frame of reference at a distance from the machine and at a predetermined distance from the magnet or magnetic part, such that the magnetoresistive sensor is operating in a dynamic part of the sensor transfer function in respect of the magnetic field produced by the magnet or a magnetic part; capturing a time-domain magnetic field signal transduced by the sensor; and using an electronic data processor to process the captured signal to obtain a vibration-based indicator of the machine's condition.

Example implementations relate to receiving vibration notifications from vibration sensors. In example implementations, a subset of a plurality of vibration sensors from which vibration notifications are expected may be identified based on a position of a train along a track. The plurality of vibration sensors may be arranged in a predetermined order on the track. Whether vibration notifications have not been received from consecutive, with respect to the predetermined order, vibration sensors in the subset may be determined.

Example implementations relate to receiving vibration notifications from vibration sensors. In example implementations, a subset of a plurality of vibration sensors from which vibration notifications are expected may be identified based on a position of a train along a track. The plurality of vibration sensors may be arranged in a predetermined order on the track. Whether vibration notifications have not been received from consecutive, with respect to the predetermined order, vibration sensors in the subset may be determined.

Disclosed in the present invention are a capillary channel environmental sensor and a preparation method therefor. The capillary channel environmental sensor comprises a transfer cavity and at least one capillary channel. The cross sectional area of the transfer cavity is greater than the cross sectional area of the capillary channel, and one end of the capillary channel is connected with the transfer cavity; an elastic transfer diaphragm is provided between the transfer cavity and an external measurement environment. A positioned droplet is provided in the interior of the capillary channel, the positioned droplet is in tight contact with the inner walls of the capillary channel and the positioned droplet is in tight contact with a transfer medium. By means of the transfer cavity and the capillary channel that are connected to one another, because the cross sectional area of the transfer cavity is larger than the cross sectional area of the capillary channel, differences in volume between the transfer cavity and the capillary channel are used to transform a small displacement in a region of large volume into a large displacement in a region of small volume. Because the positioned droplet is provided in the capillary channel, and the capillary channel environmental sensor comprises a magnetic sensing element, the magnetic sensing element causes, on the basis of movement of the positioned droplet, the change in displacement through an intermediate variable to provide high-sensitivity and low-power detection.

Disclosed is a method for detecting a value which represents the temperature of a vibrating element of an ultrasonic transducer. The ultrasonic transducer has a resonant frequency (f.sub.r). The method comprises the steps of operating the ultrasonic transducer with an electric measuring signal at a measuring frequency (f.sub.m) which is above the resonant frequency, and of detecting the absolute value of the complex impedance of the ultrasonic transducer at this measuring frequency (f.sub.m) and, building thereon, ascertaining the desired value, which is to represent the temperature of a vibrating element of an ultrasonic transducer, as a function of the detected absolute value of the complex impedance of the ultrasonic transducer at this measuring frequency (f.sub.m).

Disclosed is a method for detecting a value which represents the temperature of a vibrating element of an ultrasonic transducer. The ultrasonic transducer has a resonant frequency (f.sub.r). The method comprises the steps of operating the ultrasonic transducer with an electric measuring signal at a measuring frequency (f.sub.m) which is above the resonant frequency, and of detecting the absolute value of the complex impedance of the ultrasonic transducer at this measuring frequency (f.sub.m) and, building thereon, ascertaining the desired value, which is to represent the temperature of a vibrating element of an ultrasonic transducer, as a function of the detected absolute value of the complex impedance of the ultrasonic transducer at this measuring frequency (f.sub.m).

A compact directional high resolution magnetostrictive phased array sensor (MPAS) includes a magnetostrictive comb-shaped patch and a magnetic circuit device. The patch was machined with 24 comb fingers along its radial direction. The magnetic circuit device contains a sensing array of angularly spaced apart sensing coils and cylindrical biasing magnets. The individual sensing coils have distinct directional sensing preferences designated by the normal direction of the coil winding. The directional sensing feature of the developed MPAS is supported by the combined effect of the magnetic shape anisotropy of the comb finger formation in the patch and the sensing directionality of the sensing array. The MPAS detects the strain-induced magnetic property change on the comb-shaped patch due to the mechanical interaction between the patch and GLWs propagating in the structure under study. The array sensor enables to acquire signal data from different sensing sections within the patch by altering the rotational orientation of the magnetic circuit device.

A compact directional high resolution magnetostrictive phased array sensor (MPAS) includes a magnetostrictive comb-shaped patch and a magnetic circuit device. The patch was machined with 24 comb fingers along its radial direction. The magnetic circuit device contains a sensing array of angularly spaced apart sensing coils and cylindrical biasing magnets. The individual sensing coils have distinct directional sensing preferences designated by the normal direction of the coil winding. The directional sensing feature of the developed MPAS is supported by the combined effect of the magnetic shape anisotropy of the comb finger formation in the patch and the sensing directionality of the sensing array. The MPAS detects the strain-induced magnetic property change on the comb-shaped patch due to the mechanical interaction between the patch and GLWs propagating in the structure under study. The array sensor enables to acquire signal data from different sensing sections within the patch by altering the rotational orientation of the magnetic circuit device.

A vibration-sensor-integrated vibration exciter 4 has a chassis 21, an excitation unit 22, a magnet 23, a yoke 24, a vibration sensor 25, a fixed plate 26, a moving plate 27, coil springs 28a to 28d, a retaining plate 29, and a crisscross plate 30. Shafts 31a to 31d are fixed to the fixed plate 26. The excitation unit 22 is fixed to the crisscross plate 30. Four vibration-proof rubber members 32a to 32d are installed to the crisscross plate 30 at 90-degree pitches with same radius centering on the excitation axis of the fixed excitation unit 22. The crisscross plate 30 is installed to the retaining plate 29 through the vibration-proof rubber members 32a to 32d. A vibration applied to the chassis 21 is absorbed by the vibration-proof rubber members 32a to 32d, to prevent the yoke 24 from being dislocated in lateral direction due to the vibration.