Methods of measuring ultrasonic signal parameters in presence of interference
FIELD: physics, measurement technology.
SUBSTANCE: invention can be used to measure parameters of ultrasonic waves when investigating physical and mechanical characteristics of materials and flaw detection. Before primary measurement, the method includes obtaining information on noise, for which a radiating transducer and a receiving transducer are placed in the investigated medium, followed by exciting and receiving ultrasonic pulses, standardising the amplitude of the first arrival corresponding to the noise wave, recording the obtained pulse, followed by performing primary measurement, standardising the amplitude of the first arrival, superposition thereof with the first arrival of the pulse obtained during preliminary measurement, and performing pulse subtraction. During preliminary measurement, the radiating and receiving transducers are arranged such that after noise compensation, the first arrival is formed in the resultant pulse by the useful signal.
EFFECT: invention improves accuracy of measuring parameters of ultrasonic waves when investigating physical and mechanical characteristics of materials and flaw detection.
2 cl, 10 dwg
FIELD: radio engineering, communication.
SUBSTANCE: method includes loading a sample to a given tension value in the material and measuring the propagation time of an acoustic wave in a direction perpendicular to the loading direction, wherein the sample is stretched or compressed to tension σ, which is below the proportionality limit of the material, measuring the time t1 of the propagation of the acoustic wave between two parallel surfaces of the sample, unloading the sample, respectively compressing or stretching the sample to tension σ, measuring the time t2 of the propagation of the acoustic wave between said surfaces of the sample and determining the acoustoelastic communication coefficient using a given mathematical expression.
EFFECT: high accuracy of determining the acoustoelastic communication coefficient of material.
SUBSTANCE: transducer to be calibrated is arranged at calibration unit to excite displacement pulses therein. Received signals are registered and compared. Note here that said displacement pulses are excited with the help of friction emission acoustic source. Obtained friction emission acoustic signals are registered. Then, said signals are used to determine autocorrelation of said signals, hence, to perform the relative calibration of acoustic emission transducer.
EFFECT: higher calibration quality.
FIELD: process engineering.
SUBSTANCE: invention relates to system for making of calibration reflectors at the pipe. Portable system comprises bed to be fitted at the pipe, cutting tool, motor connected with cutting tool to drive in compliance with preselected pattern, electrode connected with cutting tool, power source connected with electrode and aforesaid pipe. Note here that said power source can feed voltage from electrode to pipe for material removal therefrom. Dielectric fluid source in contacts with via fluid with pipe for material removal. Note here that motor and power source and/or dielectric fluid source are arranged at the bed.
EFFECT: possibility to make calibration standard from high-pressure vessel pipe by cutting calibration reflectors.
15 cl, 4 dwg
SUBSTANCE: device includes a radiating element, the investigated seismoacoustic transducer, a reference mirror, an optical photodetector, a laser and an optical prism with a semitransparent mirror placed at an angle of 45° to the base. The prism is placed between the radiating element and the investigated seismoacoustic transducer. The radiating and control elements used are a piezoceramic ring with which the optical photodetector is arranged concentrically. The reference mirror and the optical photodetector are acoustically decoupled with the radiating element and the prism.
EFFECT: high sensitivity and simple design of the device.
SUBSTANCE: temperature measurement and ultrasound speed are measured in the measured gas, the speed in pure hydrogen is determined at the same temperature, and the concentration of hydrogen in gas mix is calculated using the mathematical expression considering the ratio of ultrasound speed in pure hydrogen squared to ultrasound speed in the measured mix of gases squared and the ratio of molar mass of admixtures in hydrogen to the molar mass of pure hydrogen are determined.
EFFECT: simplification of hydrogen volume concentration measuring system, increase of its long-term stability and decrease of measurements errors.
2 cl, 1 dwg
FIELD: testing technology.
SUBSTANCE: invention relates to methods of testing and operational ultrasonic product control. To improve the reliability of ultrasonic non-destructive control prior to carrying out the control the product is loaded by load sufficient to disclosure of hypothetical defect such as crack in the place of control to a value that would provide a reflection of the ultrasonic wave from the defect and made it detectable.
EFFECT: improving reliability and quality of the product is achieved.
4 cl, 5 dwg
SUBSTANCE: method includes measuring reference analogue signals using first and second microphones of an acoustic interferometer, analogue-to-digital conversion thereof, calculating a transfer function through continuous wavelet transformation of each of the measured reference signals, calculating reflection coefficients and sound absorption coefficients, presenting the calculation results in graphical form in the form of a curve of sound absorption coefficients versus frequency or geometric mean frequencies of 1/n octave bands, where n is an integer. The reference used is a deterministic analogue signal with duration of not less than 13 s with an exponentially rising frequency in the range of 100-400 Hz.
EFFECT: high accuracy of determining sound absorption coefficients of materials in the low-frequency range.
FIELD: measurement equipment.
SUBSTANCE: device to compensate error of measurement of an ultrasonic locator comprises a generator of ultrasonic pulses connected to an emitter, and the following serially connected components: a receiver, an amplifier, a threshold device, a time interval generation unit, a unit of time interval measurement and a unit of control and indication, the output of which is connected to the generator and input of the time interval generation unit, a source of reference voltage, connected to the input of the threshold device, a quartz generator connected to the unit of time interval measurement, at the same time the second generator of ultrasonic pulses is connected to the second emitter, the following components are connected in series: the second receiver, the second amplifier, the second threshold device, the second unit of time interval generation and the second unit of time interval measurement, besides, the source of reference voltage is connected to the second input of the second threshold device, the input of the second unit of time interval measurement is connected to the quartz generator, and the output of the second unit of time interval measurement is connected to the unit of control and indication, outputs of which are connected to the second generator and the second unit of time interval generation.
EFFECT: reduced error and increased stability of measurements in waveguide distribution of ultrasonic oscillations.
FIELD: measurement equipment.
SUBSTANCE: ultrasonic signal is radiated, a response signal is received, the time interval is measured between the radiated and the received signals, and the distance is detected to the reflecting surface by multiplication of the speed of ultrasound propagation in controlled medium by the measured time interval. Radiation, reception of ultrasonic signals and measurement of time intervals between radiated and received ultrasonic signals is carried out on two frequencies with different periods, then these time intervals are compared, and corrected in accordance with the present mathematical expression.
EFFECT: provision of the possibility to reduce error and increase stability of measurements in waveguide distribution of ultrasonic oscillations.
SUBSTANCE: ultrasound immersion multisection piezoelectric transducer comprises hermetic package filled with damping substance, piezoelectric cells installed inside the package and placed symmetrically in regard to the converter acoustic axis and lens placed from the side of radiation surface of piezoelectric cells, acoustic axes of piezoelectric cells are intercrossed at the longitudinal axis of the converter, polarization vector of all piezoelectric cells is directed to the radiation side or to the damping substance side, at that lens is common for all piezoelectric cells or it consists of separate sections. Piezoelectric cells are placed so that they form convex or concave surface in regard to lens, all piezoelectric cells are made with positive and negative electrodes common for them, which cover gaps between piezoelectric cells filled with polymer compound and connected to sealed electric connector. Lens and damping substance with their surfaces are faced to the formed piezoelectric cells and polymer compound and each of them adjoins electrodes at these surfaces tightly; at that lens is glued to the electrode placed at piezoelectric cells or adjoins the electrode tightly through the layer of acoustically conductive fluid.
EFFECT: potential increase of the operating zone length and expansion of direction pattern for the piezoelectric transducer at simultaneous simplification of its design.
6 cl, 3 dwg
FIELD: ultrasonic engineering; ultrasonic vibration systems for engineering purposes.
SUBSTANCE: proposed ultrasonic device that can be used for cleaning (ultrasonic baths), dispersing, homogenizing, and emulsifying materials has ultrasonic converter accommodating waveguide radiating system which is in acoustic contact with converter. Waveguide radiating system has coaxially installed bending-vibration waveguides separated by longitudinal-vibration waveguide sections. Bending-vibration waveguides are disposed in planes perpendicular to axis of longitudinal-vibration waveguide axis and spaced λ/4 apart, where λ is longitudinal-vibration wavelength. Thickness of each bending-vibration waveguide installed at antinode point of longitudinal vibrations is λ/15. Thickness of each of remaining bending-vibration waveguides is λ/18. Thicknesses of converters are set by way of calculations and experiments including attaining of maximal possible cavitation capacity during liquid sonication. Total length of radiator is a multiple of λ/2.
EFFECT: enhanced radiation effectiveness.
6 cl, 2 dwg
FIELD: measuring engineering.
SUBSTANCE: method comprises emitting pulses of ultrasonic oscillations, receiving, and recording. The emitter and receiver of ultrasonic oscillation are mounted at the opposite corners of the vessel sides, and sounding is performed along the diagonal. The results of measurements give the deviations of the side from the flatness and width of the vessel.
EFFECT: enhanced safety and accuracy of monitoring.
FIELD: investigating or analyzing materials.
SUBSTANCE: device comprises measuring chamber, two electroacoustical converters mounted inside the chamber, commutator, generator-receiver of ultrasonic oscillations, and system for measuring and recording. The device is additionally provided with the unit for control of actuators. The system for measuring and recording comprises converter, unit for processing information, unit for accumulating information, and indicator.
EFFECT: enhanced quality of monitoring.
FIELD: investigating or analyzing materials.
SUBSTANCE: method comprises exciting and receiving pulses of ultrasonic oscillations in the structure to be tested , measuring parameters of ultrasonic oscillations reflected from the interface between the parts of the integral structure, and determining the strength of part joints from the parameters. The spectrum of the bottom pulse in the shell is measured before and after assembling the integral structure at the same sites. The spectrum of the pulse reflected from the interface between the parts of the integral structure is measured, and the strength of the part joints is determined from the correlation relationship.
EFFECT: enhanced accuracy of measuring.
1 cl, 3 dwg
FIELD: inspection of strength of concrete and ferroconcrete structures.
SUBSTANCE: strength of concrete in concrete and ferroconcrete structures includes measurement of speed of ultrasound in samples-cubes and material of structures, mechanical testing of samples-cubes, building of calibration dependence of "speed of ultrasound - strength of concrete" from the results of measurements and testing of samples-cubes and determining of strength of concrete from the results of ultrasonic measurements and preliminary built calibration dependence. Average humidity of tested samples-cubes of concrete is determined on the base of different sets of samples-cubes of concrete. Average speed of propagation of ultrasound in samples-cubes and average strength of concrete cubes-samples are determined the same manner. Value of strength s set by mathematical relations.
EFFECT: improved precision; improved reliability of determination of strength of humid concrete.
FIELD: the invention refers to a frequency control of monolithic bladed disks according to their vibrator acoustic characteristics.
SUBSTANCE: the essence is in that the disk is set in rotation. Each blade on the disk is exposed to stimulation. Its acoustic response is checked and a corresponding electrical signal is generated. According to Fourier's method of rapid transformation its frequency response is determined. The electric signal and corresponding frequency response are memorized. The characteristic frequencies for each blade of the disk are determined. The disk is either accepted or rejected as defective depending on whether the obtained distribution of frequencies coincides with the preliminary defined set of prohibited frequency distributions. An additional stage is also envisaged for identification of the blade's defects by way of comparing its frequency response with preliminary defined frequency responses which are characteristic for standard defects.
EFFECT: increases efficiency and rapid operating speed of control, provides possibility of carrying on the control online and during the process of definition of the type of the defect.
7 cl, 2 dwg
FIELD: electro-acoustics and radio engineering, possible use as device for layer-wise visualization of non-homogenous zones inside internal structures of solid objects.
SUBSTANCE: ultrasound microscope has ultrasound oscillations transformer, sound guide, acoustic lens and immersion substance, researched object, display, generator of linear-frequency-modulated pulses, commutator, broadband amplifier, synchronized filter, compensating amplifier, amplitude detector, threshold device, time selector and computer, synchronization pulses generator. Computer is connected to display by its output. Outputs of synchronizing pulses generator are connected to synchronization inputs of linear-frequency-modulated pulses generator, commutator, time selector, two-coordinate scanning device and computer. First controlling output of computer is connected to second input of time selector. Second - to controlling input of two-coordinate scanning device. Output of two-coordinate scanning device is connected to second information input of computer. Second input-output of commutator is connected to transformer of ultrasound oscillations.
EFFECT: improved resolution by depth of researched sample in mode of operation of ultrasound microscope "for reflection".
FIELD: determination of degree of polymerization of composite materials.
SUBSTANCE: method can be used for determining degree of polymerization of composite material in items and structures with non-stable characteristics of surface of objects. Pulses of longitudinal acoustic waves -probing pulse, bottom pulse and pulses dissipated by structure in reverse direction - are excited and received in inspected material by means of laser optic-acoustic converter from the same surface. Spectrum of pulse dissipated by structure of material in reverse direction and spectrum of probing pulse are measured. Value of standardized power of structural noise is determined on the base of measurement of spectra mentioned above. Spectral analysis of bottom pulse is carried out by means of Fourier transform and spectrum of bottom pulse is determined. The spectrum is used for measuring frequency of main high-frequency spectral component of bottom pulse. Polymerization degree β of composite material is determined from the following correlation relation: β=φ(fmhfc, w), where fmnhfc is frequency of main high-frequency component of spectrum of ultrasonic oscillation bottom pulse, w is value of standardized power of structural noise.
EFFECT: improved precision; improved truth of results.
FIELD: testing of concrete constructions strength.
SUBSTANCE: strength of concrete in concrete and ferroconcrete constructions is determined at increased humidity of concrete and negative temperatures and, as a consequence, at presence of ice crystals in pores of concrete. According to the first version of the method, water-saturated, frozen concrete samples-cubes are used followed by building of calibration dependence of "speed of ultrasound/ strength of concrete". Strength of concrete can be improved by using the dependence. According to the second and third versions of the method, speed of ultrasound is measured in at least of ten parts of inspected area of construction followed by measurement of strengths in parts due to drilling cores out of planned pars for testing strength of cores. After that strength of concrete is calculated.
EFFECT: improved precision; improved reliability of measurement.
4 cl, 2 dwg
FIELD: inspection facilities.
SUBSTANCE: thickness of damaged concrete layer in exploitable constructions of plants is inspected at increased humidity of concrete at negative temperatures and as a result at presence of ice crystals in pores of concrete. Fault detection of concrete and ferroconcrete constructions is carried out by ultrasonic longitudinal profiling by means of mounting of irradiator motionlessly onto concrete surface and receiver is shifted step by step with a pitch of 10-100 mm along line crossing point of mounting of irradiator. Count of time of propagation of ultrasonic longitudinal waves is fixed at any installation of the receiver. Time-distance dependence between irradiator and receiver is plotted. The plot is named as velocity curve. Change in curve line is determined at the turn of damaged and non-damaged concrete. Sound velocity is found in damaged and non-damaged layers of concrete as well as humidity of non-damaged and damaged layers of concrete. After that thickness of damaged layer of concrete is found from corresponding mathematical formula.
EFFECT: improved precision and reliability of measurement of damaged layer of concrete.