578 results about "Ultrasonic guided wave" patented technology

The invention belongs to the field of nondestructive detection, and particularly relates to a power station thick-walled pipeline ultrasonic guided wave detecting method, wherein the method comprises the following steps of: selecting an ultrasonic guided wave detecting probe; selecting an ultrasonic guided wave detecting instrument; manufacturing a sensitivity test block; making a distance-amplitude curve; scanning; carrying out flaw size measurement; and verifying and grading detecting results. The detecting method is suitable for comprehensively detecting the flaws of pipelines with different pipe diameters and thicknesses, and is particularly suitable for comprehensively detecting power station thick-walled pipelines. The detecting method has the characteristics of rapidness, simpleness, safety and reliability, can overcome some limitations of a conventional nondestructive detection method, lowers the manual detection intensity and saves human and material resources.

A method for the nondestructive inspecting of coated or uncoated pipeline, using ultrasonic guided waves excited on the outer or inner pipe surface, wherein at least one or more transducers are individually or simultaneously excited to generate ultrasound, wherein multiple received signals with different focal spot positions are processed and combined to produce a reduced number of final waveforms that show defect axial positions in the pipe, wherein a data calibration scheme is utilized to adjust velocity variability for all the guided wave modes at different frequencies, and wherein the hardware arrangement has at least one pulser channel and one receiver channel for the collection and storage of signals.

The invention provides an ultrasonic guided wave detection device for quality evaluation of a composite laminated plate. In the device, ultrasonic guided wave is taken as a detection means for accurately and conveniently evaluating quality of the composite laminated plate. The detection means is achieved by the following steps: (a) performing time-frequency analysis on guided wave signals of the composite laminated plate, comparing a time-frequency distribution diagram of the signals with a theoretical time-frequency distribution curve of the guided wave, and providing a mode separation method; (b) obtaining accurate time delay information in a time-frequency domain based on good characteristics of a Gabor wavelet, combining optimal sensor placement and multi-path positioning, broadening the range of defect positioning, introducing cluster analysis and then improving accuracy and reliability of two-dimensional positioning; and (c) improving rationality and accuracy for extracting signal characteristics, and effectively separating various mode components from ultrasonic guided wave signals by adopting an improved HTT method, and taking instantaneous components as a characteristic parameter according to linear regression analysis; and (d) constructing a detection device of the ultrasonic guided wave signals, improving detection steps, designing software architecture and programming for processing the guided wave signals based on the time-frequency analysis.

The invention discloses an electromagnetic ultrasonic inclined guiding wave checking method of natural gas pipeline cracks, which is characterized in that electromagnetic ultrasonic energy exchanger units are composed of split-type broken line coils and permanent magnet blocks, and are arranged on an inner checking device in the pipeline along the inclined direction, and generated ultrasonic guiding waves have a certain checking sensitivity on cracks of each direction on the spreading route of the ultrasonic guiding waves. The inclined ultrasonic guiding wave and the supporting guiding wave after crack action of a single emitting electromagnetic ultrasonic energy exchanger unit are received by two annular receiving energy exchangers arranged on both sides of the emitting electromagnetic ultrasonic energy exchanger. A plurality of emitting energy exchanger units are arranged into an annular set, and orderly generate inclined guiding waves so as to cover the entire circumference of the pipeline wall according to time, and the positions and the sizes of the crack defects are fixed according to the received guiding wave signals and the arranging condition of the energy exchangers. The invention realizes the non-contact purpose of the cracks in the natural gas pipeline without liquid coupling check, and can be used for the crack defects of each direction.

The invention discloses a damage detection method based on instantaneous phase changing degree in the technical field of mechanical structural detection, comprising the following steps: fixing an energy converter on the surface of an object to be detected or inlaying the energy converter in the structure of the object to be detected and constructing a detection area; detecting and calculating the objected to be detected in a non-damage state by utilizing ultrasonic guided wave to obtain the flight time of the wave signal scattered by the damage; calculating to obtain the damaged coordinate position by adopting a triangle positioning method according to the flight time, and drawing multiple coordinate tracks by combining ToF assessed by each sensing path in a sensing network, wherein the converging area of the coordinate tracks is the area in which the damage can appear. The method of the invention has preferable ability of resisting the random noise interference; even though signal noise ratio (SNR) of the collected wave signal is lower, the method still can be used for accurately assessing the ToF scattered by the damage in a basic order symmetrical (S0) mode, and further successfully identifies and positions the damage by combining a triangle positioning method.

The invention discloses an ultrasonic guided-wave detecting system for the defect of a composite insulator. The ultrasonic guided-wave detecting system comprises a system master control computer, a signal generator, a power amplifier, a piezoelectric paster and a digital oscilloscope. The invention further discloses a detecting method applied to the ultrasonic guided-wave detecting system for the defect of the composite insulator. The detecting method comprises the following steps that 1, the frequency dispersion equation of propagation of guided waves in a composite insulator model is determined; 2, a corresponding frequency dispersion curve is obtained through insulator test piece related parameters tested through experiments; 3, stimulation guided wave frequency, periods and modal are determined according to a frequency dispersion curve conclusion; 4, stimulation and receiving points are selected, and defect detection of guided waves is achieved; 5, a guided wave detecting waveform is placed in a computer for data analysis processing, whether the defect exits or not it judged, and the size and type of the defect are judged. The detecting advantages of being accurate, fast, long in distance, large in range, low in cost and the like are achieved.

The invention discloses a flexible magnetostriction and magnetoelastic integrated sensor for detecting stress and defect of a wire rope. The integrated sensor comprises an inner flexible printing coil and an outer flexible printing coil, wherein the structure of the flexible printing coil can be curled and attached to the surface of the wire rope to form a single-layer or multi-layer solenoid coil which is locked by a connector and then mounted on the detected wire rope; and after the locked state is released, the solenoid coil is removed from the surface of the wire rope. The integrated sensor can work as a magnetostriction sensor and excite a longitudinal modal ultrasonic guide wave in the wire rope to perform long-distance defect detection of the wire rope or to measure the average stress of the wire rope in a certain distance based on the acoustoelastic effect of the ultrasonic guide wave; and the integrated sensor also can work as a magnetoelastic sensor and calculate the stress value of a section of the wire rope based on the magnetoelastic effect by measuring the magnetic conductivity of the material of the wire rope, or scan along the length direction of the wire rope to obtain the change of the magnetic conductivity of the material of the wire rope along the length direction and reflect the size and position of the defect.

The invention provides an ultrasonic guided wave testing method aiming at the angle steel of an electric steel tower, which belongs to the field of ultrasonic guided wave testing. The testing method is mainly and technically characterized by comprising the steps of: selecting an ultrasonic flaw detector, an ultrasonic guided wave probe and a reference block, and manufacturing an artificial defective groove on the reference block; manufacturing a distance-amplitude curve by the reference block; polishing a smooth probe movement area on the surface of the angle steel to be tested and coating a coupling agent; using the ultrasonic guided wave probe to transversely move along the probe movement area for scanning; and judging whether the angle steel to be tested is qualified or not according to the relationship between the echo signal amplitude and the distance-amplitude curve. The testing method uses the ultrasonic detector by matching with the special ultrasonic guided wave probe for exciting the ultrasonic guided wave with designated mode, is used for the nondestructive testing of the angle steel of the electric steel tower, is characterized by simpleness, fastness, safety and reliability, and has great significance in ensuring the safe and stable operation of the electric steel tower and power transmission lines.

The invention relates to a pipeline feature intelligent recognition method based on correlation analysis, belonging to the field of non-destructive detection signal analysis. The method classifies detection signals according to amplitude, shape similarity and relative size relationship between symmetric and asymmetric signals based on the correlation analysis of ultrasonic guided wave detection signals. The corresponding relationship between the categories and the pipeline features is established through tests, thereby being capable of rapidly and accurately classifying the ultrasonic guided wave detection signals.

The invention discloses a method for monitoring defects of a high-temperature steam injection pipeline. An embedded probe is connected with a probe interface of a coupler; an exciting circuit is connected with an excitation source interface of the coupler; an input end of a signal conditioning circuit is connected with a signal conditioning interface of the coupler, and an output end of the signal conditioning circuit is connected with a data acquisition card interface of a computer acquisition and processing system; the excitation source inputs a pulsed excitation signal to the embedded probe through the coupler, excites ultrasonic guided-waves in the pipeline, and generates ultrasonic echoes when encountering the defects, the ultrasonic echoes are transmitted to the embedded probe and are converted into voltage signals through the embedded probe; the voltage signals are transmitted to the signal conditioning circuit to be processed through the coupler and are output to the computer acquisition and processing system which acquires, processes and displays the ultrasonic echo signals containing defect information. The embedded probe can be embedded in an insulating layer of the pipeline, and the insulating layer of the high-temperature steam injection pipeline does not need to be damaged basically, but online detection and long-term monitoring for the defects of the pipeline can be realized, and the defects of the pipeline can be simply and accurately positioned.

The invention discloses an ultrasonic guided wave device for detecting a defect at the rail bottom of a steel rail at a long distance, which comprises a computer, a data acquisition card, a detection signal amplifier, an arbitrary waveform generator, a power amplifier, a change-over switch and a guided wave array probe. The ultrasonic guided wave device is characterized in that: the computer serves as a control center of the device, and controls the arbitrary waveform generator to generate a single-audio frequency signal of which central frequency is selected detection frequency; the single-audio frequency signal is transmitted to the guided wave array probe after passing through the power amplifier to excite guided waves of a vertical bending mode in the rail bottom of the steel rail; and under the regulation and control of the change-over switch, the guided wave array probe receives a defect reflection echo signal which is transmitted to the computer for processing and display after passing through the detection signal amplifier and the data acquisition card. The ultrasonic guided wave device realizes the rapid nondestructive detection of the defect at the rail bottom of the steel rail.

The invention discloses a guided wave signal analyzing method based on time delay. The time delay and the linear superposition are carried out on the basis of multiple groups of original signals for detecting ultrasonic guided wave, and multiple groups of original signals are separated in directions and combined into two detection result curves finally. The method comprises the steps of: mounting N sensors, wherein each sensor group corresponds to one channel, the sensors are divided into an A-ring and a B-ring and respectively set in odd number and even number, and the interval between the A-ring and the B-ring is 1/4 of the wavelength of exciting signal central frequency; selecting M windowing modulation sine waves with different central frequencies and the certain periodicity as the exciting signals, wherein the M turns of exciting signals have respective central frequency and bandwidth in the frequency domain, each turn of exciting signals covers a certain frequency range, and M*N*N groups of data are obtained by exciting and changing the central frequencies for many times; and obtaining a final pipeline detection curve graph by the calculation to realize the separation in the direction of detection and the separation of symmetrical and unsymmetrical signals, which is convenient to find out defects on the pipeline.

The invention discloses an ultrasonic guided-wave probe array fixing device used for tube fitting detection. The ultrasonic guided-wave probe array fixing device comprises a mechanical part and a signal circuit part, wherein the mechanical part comprises a circular-ring-shaped base, a plurality of positioning bolts, a plurality of spiral telescopic components, a plurality of swing rods and a plurality of probe bases; the inner diameter of the circular-ring-shaped bases is larger than the outer diameter of a detected tube fitting; two side panels of the circular-ring-shaped bases are respectively a panel A and a panel B; the positioning bolts are mounted on the panel B; each spiral telescopic component penetrates through the panel B and the panel A in sequence and then is correspondingly connected with one end of each swinging rod to regulate the opening and the closing of the swinging rod, the other end of each swinging rod is correspondingly connected with each probe base; a structure consisting of the spiral telescopic component, the swinging rods and the probe bases is uniformly distributed on the circular-ring-shaped base. The ultrasonic guided-wave probe array fixing device used for tube fitting detection, disclosed by the invention, is simple in structure, quick and convenient to operate, and capable of adapting to detection needs of tube fittings with different outer diameters within a design range.

The invention relates to a rack pipe detection robot based on the ultrasonic guided wave technology. The robot is mainly characterized in that five rotary modules and two clamps are connected in a series manner on the basis of modular structure; the two clamps can be changed according to different pipe diameters, and a claw of each clamp is provided with a guided-wave probe clamping component on which guided-wave probes different in structure and quantity can be mounted; the rotary modules expand and retract to adjust the pose of terminal clamps, the two claws hold alternately to coordinate with the rotary modules to allow for various climbs. A control system based on PC/104 bus technology is used and comprises a servo motor, an embedded computer main board, a sensor and a remote control system. The robot has the advantages of small size, light weight, simple structure and high flexibility, can detect in such manners of creeping on straight pipes and bent pipes and creeping among the pipes, and allows for rack pipe nondestructive detection on the basis of the ultrasonic guided wave technology by integrating the guided wave detection technology and the robot technology.

The invention provides a nondestructive test method for positioning defects of a composite laminated plate. The method is characterized in that a multi-probe detection mode is adopted to accurately and conveniently perform two-dimensional positioning on interfacial defects of the composite laminated plate. The method comprises the following steps: (a) arranging four sensors in a square at a certain spacing on the surface of the composite laminated plate; (b) taking each sensor in the square arrangement as an excitation sensor sequentially and two sensors adjacent to the excitation sensors as receiver sensors, thus forming a multiplex defect positioning system; (c) performing cluster analysis on position information of a plurality of groups of the defects, keeping effective data and eliminating information with obvious deviation; and (d) calculating to obtain position information of the defects based on an elliptic positioning method according to time delay, and further reducing errors by an averaging method for centering, thus performing accurate two-dimensional positioning on the defects of the composite laminated plate.

The present invention discloses a calculation method for separating symmetric and flexural mode wave packet and extracting weak signal of the bending mode. Based on the wave structure characteristic theory of axisymmetric mode and bending mode, the method uses finite element software to establish correlative model, extracts transient displacement signal of signal acquisition nodes of a guided-wave monitoring surface, and conducts delay superimposing on the collected signals on the frequency domain in accordance with relative formula; then the superimposed frequency domain signal is subjected to the inverse Fourier transform to obtain guided-wave mode wave packet of each order after separation; and Hilbert-Huang envelope is employed to calculate reflection coefficient for each mode. The method uses secondary development function of finite element software to compile the secondary development program, quantitatively analyze the influence degree of the parameters such as characteristics of defect size, location distribution, the number of defects and the center excitation frequency on the amplitude value of the flexural mode reflection echo generated from the defect locations through modal conversion, thereby integrally utilize reflection coefficients of axisymmetric mode and bending mode to evaluate the distribution of defect locations.

The invention concretely relates to an ultrasonic Lamb wave-based butt weld nondestructive testing method and belongs to the ultrasonic guided-wave nondestructive testing field. An excitation source is loaded at the end of a weld joint. Two piezoelectric patches are pasted on the upper surface and the lower surface of a plate symmetrically and excited. The generated weld joint guided-wave mode propagating along the weld joint has high energy and slow attenuation, and the long-distance testing problem can be solved. The testing system is shown in the figure, and composed of a function generator (1), a power amplifier (2), piezoelectric patches (3), an oblique incidence-type piezoelectric ultrasonic sensor (4), an oscilloscope (5) and a computer (6). By utilizing the testing system, when the ultrasonic Lamb wave encounters flaws of the weld joint, flaw echoes are generated. According to the time difference between the excitation waveforms and the waveforms of flaw echoes and the group velocity of the weld joint guided-wave mode, the distance from the flaws to the excitation source can be obtained, and therefore the effective locating of weld joint flaws can be achieved.

The invention discloses a method for quantified monitoring bolt pre-tightening torque through active ultrasonic guided wave. MFC (Macro-Fiber Composite) material elements serve as an exciter and a sensor to conduct directional excitation, acquire fluctuation response and establish a bolt pre-tightening torque reference and comparison database. In this way, on-line monitoring bolt pre-tightening torque based on the reference database is carried out. The tightness of a bolt can be rapidly monitored without disassembling a structure, the assembling cost is reduced, and the efficiency is improved. The method is simple in operation, and quantified monitoring precision for single-bolt torque value is relatively high. The MFC material elements are thin (about 0.2mm), and may not affect structure performance after being pasted.

The invention discloses a nonlinear ultrasonic guided wave detection method and a nonlinear ultrasonic guided wave detection device for pipeline micro damage. An exciting transducer capable of exciting single guided wave modal state and a matched receiving transducer are adopted, the transducers can wind a pipeline to excite axisymmetric modal states, the receiving efficiency of a second order harmonic signal is improved by a matching and corresponding receiving probe, the detection capacity of the system on second order harmonic waves of the guided waves is improved. The nonlinear change of a material is characterized by detecting the ratio of nonlinear response to propagation distance, nonlinear interference of instruments is effectively reduced, nonlinear ultrasonic guided wave evaluation of the pipeline material is realized, and nonlinear ultrasonic high sensitivity can be used for early detection of the pipeline micro defects.

The invention relates to a flexible magnetostriction and eddy integrated sensor for detecting defects of a high-voltage transmission line and belongs to the technical field of an electromagnetic acoustic sensor. An outer-layer magnetostriction sensor is printed on a substrate through a flexible printing coil and an inner-layer eddy sensor is printed on the substrate through the flexible printing coil; the flexible printing coil can be coiled into a cylindrical shape and clung to the surface of the high-voltage transmission line so as to form a solenoid coil; after the solenoid coil is clamped and fixed by a connector, the solenoid coil is mounted on a detected transmission line so as to detect the defects; and after the clamped and fixed state is released, the solenoid coil can be detached from the surface of the transmission line. The integrated sensor can be used for stimulating a longitudinal modal ultrasonic guide wave from the transmission line and detecting the defects of the whole structure of the transmission line on the basis of a magnetostriction effect; the integrated sensor also can be used for detecting complex impedance change of a sensor detecting coil due to the defects of the transmission line by utilizing a multi-channel eddy sensor and realizing the peripheral positioning for the defects on the basis of an eddy effect; and meanwhile, the deep positions of the defects in the transmission line can be confirmed on the basis of a surface action of an eddy field.