CN111678630A - Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis - Google Patents
Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis Download PDFInfo
- Publication number
- CN111678630A CN111678630A CN202010560525.6A CN202010560525A CN111678630A CN 111678630 A CN111678630 A CN 111678630A CN 202010560525 A CN202010560525 A CN 202010560525A CN 111678630 A CN111678630 A CN 111678630A
- Authority
- CN
- China
- Prior art keywords
- stress
- guided wave
- steel strand
- ultrasonic
- ultrasonic guided
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/25—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons
- G01L1/255—Measuring force or stress, in general using wave or particle radiation, e.g. X-rays, microwaves, neutrons using acoustic waves, or acoustic emission
Abstract
The invention relates to a steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis, which comprises the following steps of: obtaining a 1000mm length copied test piece of an in-service steel strand component to be detected; theoretically determining the optimal excitation frequency of the ultrasonic guided wave transmitted in the copied test piece through stress sensitivity analysis, building a steel strand single-axis stress detection hardware and software system, and obtaining a relation curve of the characteristic quantity of the ultrasonic guided wave and the stress under the frequency from a test; determining a detection area of the steel strand component in service, and acquiring an ultrasonic guided wave time domain signal by using a steel strand single-axis stress detection system; and processing the captured time domain signals to obtain actually-measured ultrasonic guided wave characteristic quantity, substituting the actually-measured ultrasonic guided wave characteristic quantity into a guided wave characteristic quantity and stress relation curve of the copied test piece, and solving the uniaxial stress of the steel strand in service. The method can realize nondestructive testing of uniaxial stress of in-service steel strands and steel round rods with different specifications, and has high testing precision.
Description
Technical Field
The invention belongs to the field of nondestructive testing of stress of steel structural members, and particularly relates to a steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis.
Background
The steel strand is used as a common tension member, bears the main tension effect in the structure, and is widely applied to multiple fields of civil engineering. In the process of stretching and service of the steel strand, the stress borne by the steel strand generates certain loss due to the performance degradation of building materials, the complex construction condition and the influence of environmental factors. In order to accurately know and master the stress state and service performance of the steel strand, it is necessary to develop an accurate, stable and efficient steel strand stress detection method.
The steel strand mainly comprises a prestressed tendon in a prestressed concrete structure, a stay cable in a cable-stayed bridge, a cable and a sling in a suspension bridge, a buried anchor rod for foundation pit support and the like. The steel strand, which is the main stressed member, has a great influence on the safety and durability of the structure. Aiming at the stress state of a steel strand in the application field of bridge guys and the like, the main detection method in the current construction is a pressure sensor method, and the detection method of the stay in service mainly comprises a frequency method based on a string vibration theory, a magnetic flux detection method based on a magnetoelastic effect and the like. The steel strand in the prestressed concrete structure penetrates into the member body, a frequency method is not suitable, and for the steel strand in the application field, a traditional stress detection method needs to embed a sensor in advance, and the traditional stress detection method comprises a strain gauge pasting method, a steel strand sensor detection method, a fiber bragg grating sensor method and the like. The embedded detection methods need to embed the sensor in advance when the component is manufactured, the sensor is difficult to repair or replace once damaged in the later service process, and the detection precision of the embedded detection methods is greatly different according to different working conditions.
Ultrasonic guided waves, which are a special ultrasonic wave propagating in a waveguide having a narrow boundary, have a general advantage of ultrasonic waves in stress detection. Further, ultrasonic guided waves have their own advantages: due to the fact that the frequency of the ultrasonic guided wave is low, attenuation of the ultrasonic guided wave in propagation in a medium is low, and the ultrasonic guided wave has obvious advantages in the field of long-distance and large-range defect and damage detection. Current research on ultrasonic guided waves has focused primarily on the detection of defects and damage in pipes, columnar structures, slab structures, and laminated composites. In the aspect of stress nondestructive testing, on the basis of the ultrasonic guided wave acoustic elasticity theory, for the ultrasonic guided wave which is propagated in the steel strand under the action of axial force, certain correlation exists between the ultrasonic characteristic quantity and the axial stress, however, due to the complexity of the guided wave propagation mode, a large amount of basic research and experimental research are still needed for utilizing the ultrasonic guided wave to carry out stress testing on the steel strand component in service.
Disclosure of Invention
Technical problem to be solved
In order to solve the problems in the prior art, the invention provides a steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis, which realizes nondestructive detection of axial stress of an in-service steel strand component.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
a steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis comprises the following steps:
s1, obtaining a 1000mm length duplication test piece of the in-service steel strand member to be detected;
s2, theoretically determining the optimal excitation frequency of the ultrasonic guided wave transmitted in the copied test piece through stress sensitivity analysis, building a steel strand uniaxial stress detection hardware and software system, and obtaining a relation curve of the ultrasonic guided wave characteristic quantity and stress under the frequency from a test;
s3, determining a detection area of the steel strand member in service, and acquiring an ultrasonic guided wave time domain signal by using a steel strand uniaxial stress detection system;
and S4, processing the captured time domain signals to obtain actually measured ultrasonic guided wave characteristic quantity, substituting the actually measured ultrasonic guided wave characteristic quantity into a guided wave characteristic quantity and stress relation curve of a copied test piece, and obtaining the uniaxial stress of the steel strand in service.
Preferably, the replica test piece is identical to the original steel strand in material, strength and nominal diameter except for length.
Preferably, the step S2 includes the following sub-steps:
s21, solving a guided wave frequency dispersion curve propagated in the copied test piece through theory, acquiring a relation curve of the sensitivity of the ultrasonic guided wave characteristic quantity and the frequency, and determining an excitation frequency range of the guided wave characteristic quantity with the highest stress sensitivity;
s22, reasonably selecting parameters of each module instrument of the hardware system, and compiling an ultrasonic guided wave excitation signal with specific central frequency in the optimal excitation frequency range by using a software system;
s23, applying uniaxial tension stress to the copied test piece step by step, emitting ultrasonic guided waves while applying the stress, collecting received signals, and storing ultrasonic guided wave characteristic quantity time domain signals in corresponding stress states;
and S24, processing the time domain signals, and acquiring a correlation test curve of the ultrasonic guided wave characteristic quantity and the uniaxial stress in the steel strand under the optimal excitation frequency.
Preferably, the data source of the relation curve of the stress sensitivity and the frequency of the ultrasonic guided wave characteristic quantity is as follows: for the same ultrasonic guided wave excitation frequency, subtracting guided wave characteristic quantity of the replication test piece in a zero stress state and a non-zero stress state, changing a frequency value, and repeating the process to obtain a relation curve of the sensitivity of the ultrasonic guided wave characteristic quantity and the frequency;
wherein, the larger the difference value is, the more sensitive the guided wave characteristic quantity at the frequency is to the uniaxial stress.
Preferably, each module instrument of the hardware system comprises: the device comprises an ultrasonic signal transmitting module, an ultrasonic signal amplifying module, an ultrasonic signal converting module, an ultrasonic guided wave signal receiving and acquiring module and a steel strand stress loading and controlling module;
the main instrument of the ultrasonic signal transmitting module is a waveform generator, and the selected waveform is a 20-peak sinusoidal signal; the ultrasonic signal amplification module is mainly provided with a signal amplifier, the gain value of output voltage is adjustable within the range of 0-26 dB, and the maximum amplification factor of the corresponding signal voltage is about 20 times;
the ultrasonic signal conversion module is a round PZT-4 flanging piezoelectric plate, the diameter of the round PZT-4 flanging piezoelectric plate is 10mm, and the central frequency of the round PZT-4 flanging piezoelectric plate is 1 MHz;
the ultrasonic guided wave signal receiving and collecting module is characterized in that the most main instrument of the module is an oscilloscope, and the selected oscilloscope can at least receive and display ultrasonic signals of 2 channels simultaneously;
the main instrument of the stress applying and controlling module is an electro-hydraulic servo universal tester which can stretch a steel strand with the maximum length of 1400 mm.
Preferably, the guided ultrasonic wave mode is a longitudinal mode, and the data sources of the guided ultrasonic wave characteristic quantity in the replica member are as follows: a PZT-4 piezoelectric patch is arranged at one end of the copying component to transmit an ultrasonic signal, and the vibration of the piezoelectric patch is effectively transmitted to the end surface or the side surface of the steel strand through a coupling agent, so that the ultrasonic longitudinal wave is transmitted in the steel strand to form ultrasonic guided waves;
and adhering a receiving end piezoelectric sheet on the other end of the copied steel strand member or on a side surface of a certain position outside a certain distance by the same method, converting the ultrasonic signal into an electric signal to be received, and acquiring data by an oscilloscope.
Preferably, according to the formula of the acoustic elasticity theory, the relationship between the ultrasonic wave speed and the stress in the uniaxial stress state is as follows:
wherein, CLIs the wave velocity of a longitudinal wave of the body propagating in the direction of uniaxial stress, CTThe wave velocity of the transverse wave of the body propagating along the uniaxial stress direction, λ, μ is a second-order elastic constant of the isotropic medium, i.e. the Lame constant, l, m, n is a Murnaghan third-order elastic constant of the isotropic medium, and σ is the uniaxial stress applied to the isotropic medium.
Preferably, the ultrasonic guided wave characteristic quantities are guided wave phase velocity and group velocity, and the extraction of the characteristic quantities should satisfy: let y1And y2Two simple harmonic waves with same amplitude and wave number and frequency which are propagated in the same medium are provided, and the wave function of the simple harmonic waves is as followsThe following steps:
y1(x,t)＝Asin(k1x-ω1t)，y2(x,t)＝Asin(k2x-ω2t)，
wherein, x is the distance from the point on the propagation direction of the simple harmonic to the initial point, and A is the amplitude of the simple harmonic;
for a simple harmonic of a single frequency, its propagation velocity in a medium is the ratio of frequency ω to wave number k, defined as the phase velocity Cpω/k; according to the superposition principle of simple harmonics, using y3Represents the combined vibration of two simple harmonic waves:
wherein the content of the first and second substances,
simple harmonic y1And y2The peak phase of the weakly synthesized wave packet always satisfies
Namely:
if the wave number and frequency of two simple harmonic lines are assumed to be close
Representing the group velocity.
Preferably, the acquisition of the ultrasonic guided wave longitudinal mode dispersion curve in the replica member should satisfy the following conditions: the solution of the wave equation is:
wherein u isrFor radial displacement, uθFor circumferential displacement, uzFor axial displacement, three types are respectively correspondedGuided wave modes-bending, torsional and longitudinal modes; m is 0 or a positive integer and represents the symmetry of vibration; t is the time of vibration of the vibration source, k is the wave number of the ultrasonic wave, and ω is the circular frequency of the ultrasonic wave.
For longitudinal mode, because of its symmetry of vibration, let m equal to 0, introduce the free boundary condition σ of stress on the surface of the rodrr＝σrz＝σrθ＝0(r＝a)，
The Pochhammer frequency dispersion equation of the longitudinal mode of the ultrasonic guided wave can be obtained by substituting the equation into a Navier equation:
L(α,β,a)-M(α,β,a)-N(α,β,a)＝0，
M(α,β,a)＝(β2-k2)2J0(αa)J1(βa)，
N(α,β,a)＝4k2αβJ1(αa)J0(βa)，
wherein a is the radius of the elastic round bar with the length being infinite isotropically, Ji(x) And the expression that the i is 0 or 1 and is 0 th order and 1 st order of the Bessel function in the 1 st class respectively.
Preferably, in step S3, for the steel strand member to be detected in service, the detection interval is determined by adhering ultrasonic transceiver sensors to both ends of the steel strand or to the side surfaces of the steel strand.
(III) advantageous effects
The invention has the beneficial effects that: the steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis provided by the invention has the following beneficial effects:
(1) the method can realize nondestructive testing of uniaxial stress of in-service steel strand structural members with different specifications, is simple and convenient to operate, has lower cost and has certain engineering application value.
(2) The method selects the frequency range of the maximum stress sensitivity of the ultrasonic guided wave characteristic quantity as the guided wave excitation frequency, and has higher sensitivity and higher precision.
(3) According to the method, the relation is established between the ultrasonic guided wave characteristic quantity and the uniaxial stress by capturing the ultrasonic guided wave characteristic quantity in the time domain range, the echo signal is stable, data acquisition is easy, and the stability is high.
In conclusion, the steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis provided by the invention realizes nondestructive detection of uniaxial stress in-service steel strand structural members with different specifications, and is simple and convenient in test process, convenient in test instrument installation, low in cost and easy to realize. The method can be used for detecting the uniaxial stress of the steel strand structural members under construction and already constructed, and can also be used for detecting the welding residual stress and loading stress of other metal round rod members.
Drawings
FIG. 1 is a comparison graph of guided wave phase velocity dispersion curves in steel round rods with different diameters under zero stress.
FIG. 2 is a comparison graph of the guided wave group velocity dispersion curves in steel round rods with different diameters under zero stress.
FIG. 3 is a graph showing the relationship between the stress sensitivity of guided phase velocity and the frequency in the case of round rods with different diameters.
FIG. 4 is a graph showing the relationship between the stress sensitivity of the group velocity and the frequency of the guided waves in the round rods with different diameters.
FIG. 5 is a frame diagram of a steel strand uniaxial stress detection hardware system in an embodiment of the invention.
FIG. 6 is a 20-peak sinusoidal ultrasonic excitation signal with a center frequency of 200kHz modulated by a hanning window in an embodiment of the present invention.
Fig. 7 shows ultrasonic transmit-receive time-domain signals acquired according to an embodiment of the present invention.
Fig. 8 shows the ultrasonic guided wave transmitting and receiving signals after filtering and denoising processing according to the embodiment of the invention.
FIG. 9 shows the bonding process of the piezoelectric plates at the two ends of the steel strand test piece B1 in the embodiment of the invention.
Fig. 10 is a comparison graph of time courses of B1 steel strand guided wave received signals under different stresses measured by the embodiment of the invention.
FIG. 11 shows the relationship between the time and group velocity of guided wave sound and uniaxial stress in a B1 steel strand measured according to an embodiment of the present invention.
FIG. 12 is a comparison graph of the time course of the received signals of-14 mm for ribbed bars under different uniaxial stresses measured by the example of the invention.
FIG. 13 is a comparison graph of the time course of the received signal of 18mm for an optical round steel rod under different uniaxial stresses measured by the example of the invention.
FIG. 14 shows the relationship between the time and group velocity of guided waves and uniaxial stress in-14 mm of ribbed steel bars measured according to an embodiment of the present invention.
FIG. 15 shows the relationship between the acoustic time and group velocity of guided waves in an optical round steel rod of 18mm and uniaxial stress measured in the example of the present invention.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.
In the steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis of the embodiment, the principle of the steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis is as follows:
the steel strand mainly bears uniaxial tensile stress during normal operation. According to the theory of acoustic elasticity, the propagation characteristics of ultrasonic waves in a medium are influenced by stress, and the influence is mainly reflected in that the propagation speed of the ultrasonic waves changes along with the change of the stress. However, the conventional acoustoelastic theory involves three-dimensional spatial stress including longitudinal waves and transverse waves propagating in three mutually orthogonal directions, and the relationship between stress and wave velocity is expressed as a relationship between a plurality of components. In the steel strand, the main propagation form of the ultrasonic wave is an ultrasonic guided wave longitudinal mode propagating along the direction of tensile stress. Therefore, the acoustic-elastic theory formula in the steel strand can be simplified into the relation between the ultrasonic wave velocity and the stress in a uniaxial stress state, and the specific expression is shown in formula (1) and formula (2):
wherein, CLThe wave velocity of the longitudinal wave of the body propagating along the uniaxial stress direction; cTThe wave velocity of the transverse wave of the body propagating along the uniaxial stress direction; λ, the second order elastic constant of the isotropic medium, the Lame constant; l, m and n are third-order elastic constants of the isotropic medium, namely Murnaghan constants; σ is the uniaxial stress to which the isotropic medium is subjected.
By solving equations (1) and (2) numerically using uniaxial stress as a single variable, a relationship curve between the wave velocities of longitudinal and transverse bulk waves and uniaxial stress in a steel material under uniaxial stress can be obtained.
In the test, the ultrasonic guided waves propagated in the steel strand are actually complex wave packets formed by ultrasonic waves of different frequencies in a certain frequency range, which are propagated at respective speeds and superposed on each other, under the influence of various conditions. Suppose y1And y2The two lines of simple harmonic waves with the same amplitude and the similar wave number and frequency are propagated in the same medium, and the wave functions of the simple harmonic waves are shown in formulas (3) and (4). For a simple harmonic of a single frequency, its propagation velocity in a medium is the ratio of frequency ω to wave number k, defined as the phase velocity Cpω/k. According to the superposition principle of simple harmonics, using y3The resultant vibration of two simple harmonic waves is shown in equation (5).
y1(x,t)＝Asin(k1x-ω1t) (3)
y2(x,t)＝Asin(k2x-ω2t) (4)
Wherein x is the distance from a point in the propagation direction of the simple harmonic to the initial point; a is the amplitude of the simple harmonic.
From the formula (5), the simple harmonic y1And y2The combined vibration of (1) is equivalent to that one simple harmonic wave is modulated by another simple harmonic wave, and the peak phase of the formed wave packet always satisfies the condition
Namely:
since the wave numbers and frequencies of two assumed simple harmonic lines are close, equation (8) can be further simplified to equation (9), where C isgRepresenting group velocity, we can therefore understand group velocity as the moving velocity of the peak point of the wave packet, which is consistent with the interpretation of group velocity by many scholars (e.g., limonitic citizens).
For a surface free isotropic infinite length elastic round bar, the solution of its wave equation is divided into three displacement components: radial displacement urCircumferential displacement uθAnd axial displacement uzThe three displacement components respectively correspond to three vibration modes, or guided wave modes, of the medium in the round rod: a bending mode, a torsional mode, and a longitudinal mode. The three displacement components can be expressed in a cylindrical coordinate system, see equations (10) to (12):
ur＝U(r)cosmθei(kz-ωt)(10)
uθ＝V(r)sinmθei(kz-ωt)(11)
uz＝W(r)cosmθei(kz-ωt)(12)
wherein m is 0 or a positive integer and represents the symmetry of vibration; t is the time of vibration of the vibration source, k is the wave number of the ultrasonic wave, and ω is the circular frequency of the ultrasonic wave.
In this embodiment, theoretical and experimental studies are performed based on the longitudinal mode of the ultrasonic guided wave, and for the longitudinal mode, because of the symmetry of its vibration, m is 0, equations (10) to (12) are substituted, the circumferential displacement is zero, and the free boundary condition of the surface stress of the round bar is introduced:
σrr＝σrz＝σrθ＝0(r＝a) (13)
the Pochhammer frequency dispersion equation (14) of the longitudinal mode of the ultrasonic guided wave can be obtained by combining the equations (10), (12) and (13) with a physical equation and a geometric equation and substituting the equations into a Navier equation, and the left side of the frequency dispersion equation is the difference of three functions L (alpha, beta, a), M (alpha, beta, a) and N (alpha, beta, a):
L(α,β,a)-M(α,β,a)-N(α,β,a)＝0 (14)
M(α,β,a)＝(β2-k2)2J0(αa)J1(βa) (16)
N(α,β,a)＝4k2αβJ1(αa)J0(βa) (17)
wherein a is the radius of the elastic round bar with the length being infinite isotropically, Ji(x) And the expression that the i is 0 or 1 and is 0 th order and 1 st order of the Bessel function in the 1 st class respectively.
As can be seen from the expressions (14) to (17), the influence factor of the longitudinal mode of the ultrasonic guided wave propagating in the circular rod is the radius a of the waveguide in addition to the parameters of the ultrasonic wave, i.e., the circular frequency ω and the wave number k, and therefore, the influence of the change in the diameter of the circular rod must be considered in the subsequent numerical calculation. In addition, the Pochhammer dispersion equation has two variables α and β, which are expressed as follows:
wherein, CL、CTThe meanings of ω, k are identical to those given above.
As can be seen from equations (18) and (19), α and β are parameters comprehensively characterizing the ultrasonic frequency, wave number, and bulk wave velocity. For a medium under a specific uniaxial stress, the wave velocity of the bulk wave is determined, leaving three variables in equation (14): radius a of the round bar, round frequency ω of the ultrasonic wave, and wave number k. Substituting parameters such as density rho and elastic constant E of the material, and obtaining the relation between the frequency and the wave number of the ultrasonic guided wave circle in the round rod with the specific diameter under the specific stress through numerical solution, and further obtaining the relation between the phase velocity and the group velocity and the frequency, namely the dispersion curve of the phase velocity and the group velocity according to the theoretical formula of the phase velocity and the group velocity. By changing the diameter of the round rods, the ultrasonic guided wave frequency dispersion curves of the round rods with different diameters in the same uniaxial stress state can be compared.
Based on the theoretical derivation, the implementation process of the method can be summarized into four major steps. The first step is the duplication of the steel strand member in service; the second step is that the optimal excitation frequency of the ultrasonic guided wave transmitted in the copied test piece is theoretically determined through stress sensitivity analysis, a steel strand single-axis stress detection hardware and software system is set up, and a relation curve of the ultrasonic guided wave characteristic quantity and the stress under the frequency is obtained from a test; determining a detection area of the steel strand member in service, and acquiring an ultrasonic guided wave time domain signal by using a steel strand uniaxial stress detection system; and fourthly, processing the captured time domain signals to obtain actually measured ultrasonic guided wave characteristic quantity, substituting the actually measured ultrasonic guided wave characteristic quantity into a guided wave characteristic quantity and stress relation curve of the copied test piece, and solving the uniaxial stress of the steel strand in service. The method comprises the following four steps:
firstly, duplicating an in-service steel strand component: the in-service steel strand member is generally not detachable, and the relation curve of the ultrasonic guided wave characteristic quantity and the stress under the frequency needs to be obtained in the implementation process of the method. Therefore, a 1000 mm-length steel strand with the same material, strength and nominal diameter as those of the in-service steel strand is selected as a replication member, and the replication member is tested on the steel strand.
And secondly, theoretically determining the optimal excitation frequency of the ultrasonic guided wave transmitted in the copied test piece through stress sensitivity analysis, building a steel strand uniaxial stress detection hardware and software system, and acquiring a relation curve of the characteristic quantity of the ultrasonic guided wave and the stress under the frequency from a test: the specific steps of this step are:
(1) according to the Pochhammer dispersion equation (14), the uniaxial stress on the round rod is considered to be zero, and only a variable of the radius a is left in the Pochhammer dispersion equation. And (3) theoretically solving the ultrasonic characteristic quantity dispersion curve of the steel round rod replica under zero stress, as shown in the figures 1 and 2.
(2) And (4) carrying out numerical calculation by utilizing GUIGUW software, comparing the ultrasonic guided wave characteristic quantities in a zero stress state and a non-zero stress state under the same frequency, and taking the difference between the two as the sensitivity of the wave speed to the uniaxial stress. Changing excitation frequency, comparing the sensitivity of the ultrasonic guided wave characteristic quantity to uniaxial stress at each frequency in the frequency range of 0-1000 kHz, obtaining a relation curve of the sensitivity of the ultrasonic guided wave characteristic quantity and the frequency, and determining the excitation frequency range with the highest stress sensitivity of the guided wave characteristic quantity from the relation curve as shown in figures 3 and 4;
(3) the built steel strand uniaxial stress detection hardware system is shown in fig. 5, parameters of each module instrument of the hardware system are reasonably selected, and an ultrasonic guided wave excitation signal with specific central frequency is compiled in an optimal excitation frequency range by using a software system, wherein the excitation signal is shown in fig. 6;
(4) and (3) applying uniaxial tension stress to the copied test piece step by step, transmitting ultrasonic guided waves while applying the stress, collecting received signals, storing ultrasonic guided wave characteristic quantity time domain signals in corresponding stress states, and transmitting and receiving the time domain signals as shown in fig. 7. The specific method comprises the following steps: a PZT-4 piezoelectric patch is arranged at one end of the replication component to transmit ultrasonic signals, and the vibration of the piezoelectric patch is effectively transmitted to the end face or the side face of the steel strand through a coupling agent. And adhering a receiving end piezoelectric sheet on the other end of the copied steel strand member or on a side surface of a certain position outside a certain distance by the same method, converting the ultrasonic signal into an electric signal to be received, and acquiring data by an oscilloscope.
(5) And processing the time domain signal to obtain a correlation test curve of the ultrasonic guided wave characteristic quantity and the uniaxial stress under the optimal excitation frequency in the steel strand.
Thirdly, determining a detection area of the steel strand component in service, and acquiring ultrasonic guided wave signals and accurately capturing characteristic quantities by using a steel strand single-axis stress detection system: the specific operation of this step is as follows:
(1) smoothing the detection point of the in-service steel strand component, coating a coupling agent on the detection part, and fixing the probe on the steel strand;
(2) connecting an instrument, and debugging a detection system to enable a stable ultrasonic time domain signal to appear on a display screen of the oscilloscope;
(3) and adjusting the ultrasonic transmitter to transmit the ultrasonic signal with the optimal excitation frequency of the steel strand of the specification, and acquiring the ultrasonic time domain signal of the detection point on a display screen of the oscilloscope.
And fourthly, processing the captured ultrasonic signals, substituting the actually measured ultrasonic guided wave characteristic quantity into the ultrasonic guided wave characteristic quantity and stress relation curve of the copied test piece, and solving the uniaxial stress size of the steel strand in service: the specific operation of this step is as follows:
(1) filtering and denoising the ultrasonic guided wave signals by using a steel strand uniaxial stress detection software system;
(2) acquiring the acoustic time difference between the peak point of the wave packet of the transmitted signal (as the signal transmission time) and the peak point of the first wave packet of the received signal (as the signal reception time), as shown in fig. 8;
(3) and calculating the group velocity of the guided waves according to the acoustic time difference, and bringing the group velocity characteristic quantity of the copied test piece into a stress relation curve to obtain the uniaxial stress of the steel strand in service.
Example 1
The invention selects a commonly used 7-wire steel strand to copy a test piece, takes the loading test of a B1 steel strand test piece as an example, the nominal diameter of the test piece is 15.20mm, the nominal cross-sectional area is 140mm2, the length is 1057mm, and the tensile strength is 1860 MPa. The assay was carried out according to the assay procedure mentioned in example 1.
The method comprises the first step of obtaining the excitation frequency most sensitive to stress of the ultrasonic guided wave propagating in the steel strand with the same diameter by using a theory.
Secondly, paste the PZT piezoelectric patches on steel strand wires both ends cross-section through the ultrasonic wave couplant and send and receive the signal, adopt the special anchor clamps of steel strand wires of taking the tooth to carry out the centre gripping to the steel strand wires both ends, have better centre gripping effect for letting anchor clamps to the steel strand wires, wrap up steel strand wires both ends side with special aluminium skin of steel strand wires before the centre gripping, the influence minimizing that makes the tooth of anchor clamps bite, avoid the steel strand wires test piece because of the destruction that the stress concentration of anchor clamps centre gripping length within range leads to, as shown in figure 9.
And thirdly, aiming at the steel strand test piece with the tensile strength of 1860MPa in the test, the yield stress of the steel strand test piece is 1670MPa, the stress interval of loading is set to be 100MPa, the upper limit of the loading stress is 1400MPa, and the steel strand in the whole process of the test is ensured to be in the elastic working range. And acquiring ultrasonic guided wave time domain signals in each stress state, and loading and stabilizing the load continuously in a stepped manner until the ultrasonic guided wave signals in the last stress state are acquired and stored.
And fourthly, guiding the ultrasonic guided wave signal files stored in the stress states into an acquisition module for processing and sound of the ultrasonic guided wave signals, filtering and denoising the received signals through Matlab, and acquiring sound corresponding to a peak point of a guided wave packet in the signals, as shown in FIG. 10.
And fifthly, calculating a group velocity characteristic quantity test value of the ultrasonic guided wave under the uniaxial stress state by combining the length (sound path) of the steel strand test piece, wherein the guided wave sound time and the group velocity under each stress state are shown in table 1, and drawing a relation curve of the group velocity characteristic quantity and the stress of the B1 steel strand test piece, as shown in fig. 11.
TABLE 1B1 data sheet of the results of the steel strand loading test
Example 2
The invention selects two different steel round bar test pieces: the first is HRB400 level ribbed steel bar, the second is 45# steel smooth round steel bar, and the serial numbers and the detailed parameters of two steel round bar test pieces are shown in table 2. The assay was carried out according to the assay procedure mentioned in example 1.
TABLE 2 summary table of steel round bar test piece parameters
The method comprises the first step of obtaining the excitation frequency most sensitive to stress of the ultrasonic guided waves propagated in the steel round rods with the same diameter by using a theory.
And secondly, the PZT piezoelectric sheet is attached to both end sections by an ultrasonic coupling agent to transmit and receive signals, and is fixed in the same manner as in example 1.
And thirdly, setting the upper limit of the loaded stress to be 360MPa to ensure that the test piece is in an elastic working range in the whole loading process because the yield strengths of the two steel round bar test pieces are relatively close. In order to set a reasonable stress interval, the stress value loaded at each stage is controlled to be 10% -20% of the upper limit of the stress, so that the loaded stress interval is set to be 60MPa, and the loading speed is set to be 2 MPa/s. And the stress retention time of each stage is set to 45s, so that ultrasonic guided wave signals in the stress state are acquired. And compiling a ribbed steel bar loading schedule table 3 and a smooth round steel bar loading schedule table 4 according to the parameters.
TABLE 3 ribbed bar loading schedule
TABLE 4 round optical rod loading system table
And respectively carrying out loading tests on the ribbed steel bar-14 test piece and the optical round steel bar-18 test piece according to a formulated loading schedule, and acquiring ultrasonic guided wave time domain signals in each stress state until the ultrasonic guided wave signals in the last stress state are acquired and stored.
And fourthly, guiding the ultrasonic guided wave signal files stored in the stress states into an acquisition module for processing and sound of the ultrasonic guided wave signals, filtering and denoising the received signals through Matlab, and acquiring sound corresponding to the peak point of the guided wave packet in the signals, as shown in FIGS. 12 and 13.
And fifthly, calculating a group velocity characteristic quantity test value of ultrasonic guided waves in the uniaxial stress state by combining the lengths (sound paths) of the ribbed steel bar-14 and the optical round steel bar-18 test piece, wherein the guided wave sound time and the group velocity in each stress state are shown in tables 5 and 6, and drawing a relation curve between the group velocity characteristic quantity and the stress of the ribbed steel bar-14 and the optical round steel bar-18 test piece, as shown in fig. 14 and 15.
TABLE 5 Loading test result data sheet of ribbed bar-1 test piece
TABLE 6 Loading test result data table of smooth round steel bar-1 test piece
The embodiment shows that the steel strand single-shaft stress detection method based on ultrasonic guided wave stress sensitivity analysis can realize nondestructive detection of single-shaft stress of steel strands and steel round rods in service with different specifications, and the test instrument is convenient to operate, low in detection cost and easy to realize; meanwhile, the sensitivity is high, the precision is high, data acquisition is easy, and the stability is high. The method can be used for detecting the uniaxial stress of the steel strand and the steel round rod under construction and built, and can also be used for detecting the welding residual stress and the loading stress of other metal round rods.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (10)
1. A steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis is characterized by comprising the following steps: the method comprises the following steps:
s1, obtaining a 1000mm length duplication test piece of the in-service steel strand member to be detected;
s2, theoretically determining the optimal excitation frequency of the ultrasonic guided wave transmitted in the copied test piece through stress sensitivity analysis, building a steel strand uniaxial stress detection hardware and software system, and obtaining a relation curve of the ultrasonic guided wave characteristic quantity and stress under the frequency from a test;
s3, determining a detection area of the steel strand member in service, and acquiring an ultrasonic guided wave time domain signal by using a steel strand uniaxial stress detection system;
and S4, processing the captured time domain signals to obtain actually measured ultrasonic guided wave characteristic quantity, substituting the actually measured ultrasonic guided wave characteristic quantity into a guided wave characteristic quantity and stress relation curve of a copied test piece, and obtaining the uniaxial stress of the steel strand in service.
2. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 1,
except for the length, the material, the strength and the nominal diameter of the copied test piece are the same as those of the original steel strand.
3. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 1,
the step S2 includes the following sub-steps:
s21, solving a guided wave frequency dispersion curve propagated in the copied test piece through theory, acquiring a relation curve of the sensitivity of the ultrasonic guided wave characteristic quantity and the frequency, and determining an excitation frequency range of the guided wave characteristic quantity with the highest stress sensitivity;
s22, reasonably selecting parameters of each module instrument of the hardware system, and compiling an ultrasonic guided wave excitation signal with specific central frequency in the optimal excitation frequency range by using a software system;
s23, applying uniaxial tension stress to the copied test piece step by step, emitting ultrasonic guided waves while applying the stress, collecting received signals, and storing ultrasonic guided wave characteristic quantity time domain signals in corresponding stress states;
and S24, processing the time domain signals, and acquiring a correlation test curve of the ultrasonic guided wave characteristic quantity and the uniaxial stress in the steel strand under the optimal excitation frequency.
4. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
the data source of the relation curve of the ultrasonic guided wave characteristic quantity stress sensitivity and the frequency is as follows: for the same ultrasonic guided wave excitation frequency, subtracting guided wave characteristic quantity of the replication test piece in a zero stress state and a non-zero stress state, changing a frequency value, and repeating the process to obtain a relation curve of the sensitivity of the ultrasonic guided wave characteristic quantity and the frequency;
wherein, the larger the difference value is, the more sensitive the guided wave characteristic quantity at the frequency is to the uniaxial stress.
5. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
each module instrument of the hardware system comprises: the device comprises an ultrasonic signal transmitting module, an ultrasonic signal amplifying module, an ultrasonic signal converting module, an ultrasonic guided wave signal receiving and acquiring module and a steel strand stress loading and controlling module;
the main instrument of the ultrasonic signal transmitting module is a waveform generator, and the selected waveform is a 20-peak sinusoidal signal; the ultrasonic signal amplification module is mainly provided with a signal amplifier, the gain value of output voltage is adjustable within the range of 0-26 dB, and the maximum amplification factor of the corresponding signal voltage is about 20 times;
the ultrasonic signal conversion module is a round PZT-4 flanging piezoelectric plate, the diameter of the round PZT-4 flanging piezoelectric plate is 10mm, and the central frequency of the round PZT-4 flanging piezoelectric plate is 1 MHz;
the ultrasonic guided wave signal receiving and collecting module is characterized in that the most main instrument of the module is an oscilloscope, and the selected oscilloscope can at least receive and display ultrasonic signals of 2 channels simultaneously;
the main instrument of the stress applying and controlling module is an electro-hydraulic servo universal tester which can stretch a steel strand with the maximum length of 1400 mm.
6. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
the ultrasonic guided wave mode is a longitudinal mode, and the ultrasonic guided wave characteristic quantity data sources in the copied component are as follows: a PZT-4 piezoelectric patch is arranged at one end of the copying component to transmit an ultrasonic signal, and the vibration of the piezoelectric patch is effectively transmitted to the end surface or the side surface of the steel strand through a coupling agent, so that the ultrasonic longitudinal wave is transmitted in the steel strand to form ultrasonic guided waves;
and adhering a receiving end piezoelectric sheet on the other end of the copied steel strand member or on a side surface of a certain position outside a certain distance by the same method, converting the ultrasonic signal into an electric signal to be received, and acquiring data by an oscilloscope.
7. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
according to the acoustic elastic theory formula, the relation between the ultrasonic wave speed and the stress in the uniaxial stress state is as follows:
wherein, CLIs the wave velocity of a longitudinal wave of the body propagating in the direction of uniaxial stress, CTThe wave velocity of the transverse wave of the body propagating along the uniaxial stress direction, λ, μ is a second-order elastic constant of the isotropic medium, i.e. the Lame constant, l, m, n is a Murnaghan third-order elastic constant of the isotropic medium, and σ is the uniaxial stress applied to the isotropic medium.
8. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
the ultrasonic guided wave characteristic quantity is guided wave phase velocity and group velocity, and the extraction of the characteristic quantity should satisfy: let y1And y2Two simple harmonic waves with the same amplitude and similar wave number and frequency are propagated in the same medium, and the wave function is as follows:
y1(x，t)＝Asin(k1x-ω1t)，y2(x，t)＝Asin(k2x-ω2t)，
wherein, x is the distance from the point on the propagation direction of the simple harmonic to the initial point, and A is the amplitude of the simple harmonic;
for a simple harmonic of a single frequency, its propagation velocity in a medium is the ratio of frequency ω to wave number k, defined as the phase velocity Cpω/k; according to the superposition principle of simple harmonics, using y3Represents the combined vibration of two simple harmonic waves:
wherein the content of the first and second substances,
simple harmonic y1And y2The peak phase of the weakly synthesized wave packet always satisfies
Namely:
if the wave number and frequency of two simple harmonic lines are assumed to be close
Representing the group velocity.
9. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 3,
the acquisition of the ultrasonic guided wave longitudinal mode dispersion curve in the copied component meets the following requirements: the solution of the wave equation is:
ur＝U(r)cos mθei(kz-ωt)，uθ＝V(r)sin mθei(kz-ωt)，uz＝W(r)cos mθei(kz-ωt)，
wherein u isrFor radial displacement, uθFor circumferential displacement, uzThe axial displacement corresponds to three guided wave modes, namely a bending mode, a torsion mode and a longitudinal mode; m is 0 or a positive integer and represents the symmetry of vibration; t is the time of vibration of the vibration source, k is the wave number of the ultrasonic wave, and ω is the circular frequency of the ultrasonic wave.
For longitudinal mode, because of its symmetry of vibration, let m equal to 0, introduce the free boundary condition σ of stress on the surface of the rodrr＝σrz＝σrθ＝0(r＝a)，
The Pochhammer frequency dispersion equation of the longitudinal mode of the ultrasonic guided wave can be obtained by substituting the equation into a Navier equation:
L(α，β，a)-M(α，β，a)-N(α，β，a)＝0，
M(α，β，a)＝(β2-k2)2J0(αa)J1(βa)，
N(α，β，a)＝4k2αβJ1(αa)J0(βa)，
wherein a is the radius of the elastic round bar with the length being infinite isotropically, Ji(x) And the expression that the i is 0 or 1 and is 0 th order and 1 st order of the Bessel function in the 1 st class respectively.
10. The method for detecting the uniaxial stress of the steel strand based on the ultrasonic guided wave stress sensitivity analysis according to claim 1, wherein the method comprises the following steps:
in step S3, for the in-service steel strand member to be detected, the detection interval is determined by attaching ultrasonic transceiver sensors to both ends of the steel strand or to the side surfaces of the steel strand.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010560525.6A CN111678630B (en) | 2020-06-18 | 2020-06-18 | Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010560525.6A CN111678630B (en) | 2020-06-18 | 2020-06-18 | Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111678630A true CN111678630A (en) | 2020-09-18 |
| CN111678630B CN111678630B (en) | 2021-08-06 |
Family
ID=72455748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010560525.6A Active CN111678630B (en) | 2020-06-18 | 2020-06-18 | Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111678630B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112903157A (en) * | 2021-01-19 | 2021-06-04 | 吉林大学 | Stress monitoring method of circular tube type structure based on longitudinal mode ultrasonic guided waves |
| CN114216583A (en) * | 2021-12-16 | 2022-03-22 | 北京大学 | SH guided wave-based temperature stress online monitoring system and monitoring method thereof |
| CN114577907A (en) * | 2021-12-31 | 2022-06-03 | 哈尔滨工业大学（深圳） | Curved panel member damage detection method and system and storage medium |
| CN114739546A (en) * | 2022-05-23 | 2022-07-12 | 天津大学 | Stress detection method based on ultrasonic guided waves and suitable for section of any shape |
| CN114877820A (en) * | 2021-03-22 | 2022-08-09 | 重庆交通大学 | Method for monitoring foundation pile of high-pile wharf based on unfavorable incentive recognition |
| CN114878042A (en) * | 2022-05-09 | 2022-08-09 | 浙江大学 | Device and method for measuring axial stress of circular tube based on torsional mode ultrasonic guided waves |
| CN115560890A (en) * | 2022-10-11 | 2023-01-03 | 北京工业大学 | Steel strand prestress identification method based on ultrasonic guided wave energy leakage ratio |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1828287A (en) * | 2006-04-14 | 2006-09-06 | 北京工业大学 | No-harm detection method for fluid pipe with adhesive and elastic cladding |
| CN101441199A (en) * | 2008-12-26 | 2009-05-27 | 北京工业大学 | High-order longitudinal wave guide measuring method of steel strand prestress |
| CN202661448U (en) * | 2012-02-15 | 2013-01-09 | 北京工业大学 | Arbitrary waveform excitation board card for exciting piezoelectric transducer array to generate ultrasonic guided waves |
| CN104614105A (en) * | 2013-12-05 | 2015-05-13 | 北京交通大学 | Device and method for monitoring rail stress based on ultrasonic guided-wave |
| KR20180026904A (en) * | 2016-09-05 | 2018-03-14 | (주)품질안전기술원 | Flexible type variable angle wedge for ultrasonic inspection and a guided wave testing system |
| EP3385694A1 (en) * | 2017-04-05 | 2018-10-10 | Honeywell International Inc. | System and method for detecting structural damage in a component |
-
2020
- 2020-06-18 CN CN202010560525.6A patent/CN111678630B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1828287A (en) * | 2006-04-14 | 2006-09-06 | 北京工业大学 | No-harm detection method for fluid pipe with adhesive and elastic cladding |
| CN101441199A (en) * | 2008-12-26 | 2009-05-27 | 北京工业大学 | High-order longitudinal wave guide measuring method of steel strand prestress |
| CN202661448U (en) * | 2012-02-15 | 2013-01-09 | 北京工业大学 | Arbitrary waveform excitation board card for exciting piezoelectric transducer array to generate ultrasonic guided waves |
| CN104614105A (en) * | 2013-12-05 | 2015-05-13 | 北京交通大学 | Device and method for monitoring rail stress based on ultrasonic guided-wave |
| KR20180026904A (en) * | 2016-09-05 | 2018-03-14 | (주)품질안전기술원 | Flexible type variable angle wedge for ultrasonic inspection and a guided wave testing system |
| EP3385694A1 (en) * | 2017-04-05 | 2018-10-10 | Honeywell International Inc. | System and method for detecting structural damage in a component |
Non-Patent Citations (1)
| Title |
|---|
| LU WEI: "Reconstruction to Sensor Measurements Based on a Correlation Model of Monitoring Data", 《APPLIED SCIENCE》 * |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112903157A (en) * | 2021-01-19 | 2021-06-04 | 吉林大学 | Stress monitoring method of circular tube type structure based on longitudinal mode ultrasonic guided waves |
| CN112903157B (en) * | 2021-01-19 | 2021-11-09 | 吉林大学 | Stress monitoring method of circular tube type structure based on longitudinal mode ultrasonic guided waves |
| CN114877820A (en) * | 2021-03-22 | 2022-08-09 | 重庆交通大学 | Method for monitoring foundation pile of high-pile wharf based on unfavorable incentive recognition |
| CN114877820B (en) * | 2021-03-22 | 2023-06-02 | 重庆交通大学 | High pile wharf foundation pile monitoring method based on unfavorable incentive recognition |
| CN114216583A (en) * | 2021-12-16 | 2022-03-22 | 北京大学 | SH guided wave-based temperature stress online monitoring system and monitoring method thereof |
| CN114216583B (en) * | 2021-12-16 | 2022-08-26 | 北京大学 | SH guided wave-based temperature stress online monitoring system and monitoring method thereof |
| CN114577907A (en) * | 2021-12-31 | 2022-06-03 | 哈尔滨工业大学（深圳） | Curved panel member damage detection method and system and storage medium |
| CN114878042A (en) * | 2022-05-09 | 2022-08-09 | 浙江大学 | Device and method for measuring axial stress of circular tube based on torsional mode ultrasonic guided waves |
| CN114739546A (en) * | 2022-05-23 | 2022-07-12 | 天津大学 | Stress detection method based on ultrasonic guided waves and suitable for section of any shape |
| CN114739546B (en) * | 2022-05-23 | 2022-12-02 | 天津大学 | Stress detection method based on ultrasonic guided waves and suitable for section of any shape |
| CN115560890A (en) * | 2022-10-11 | 2023-01-03 | 北京工业大学 | Steel strand prestress identification method based on ultrasonic guided wave energy leakage ratio |
| CN115560890B (en) * | 2022-10-11 | 2024-01-09 | 北京工业大学 | Steel strand prestress identification method based on ultrasonic guide wave energy leakage ratio |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111678630B (en) | 2021-08-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111678630B (en) | Steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis | |
| Chaki et al. | Guided ultrasonic waves for non-destructive monitoring of the stress levels in prestressed steel strands | |
| Chen et al. | Measurement of tensile forces in a seven-wire prestressing strand using stress waves | |
| Shah et al. | Efficiency and sensitivity of linear and non-linear ultrasonics to identifying micro and macro-scale defects in concrete | |
| CN101806778B (en) | Method for non-linear ultrasonic online detection of early fatigue damage of metal material | |
| Kwun et al. | Experimental observation of elastic‐wave dispersion in bounded solids of various configurations | |
| Xu et al. | Detecting broken-wire flaws at multiple locations in the same wire of prestressing strands using guided waves | |
| CN1978977A (en) | Supersonic guide-wave time reversion detection apparatus and method for defect of pipeline | |
| Dubuc et al. | Higher order longitudinal guided wave modes in axially stressed seven-wire strands | |
| CN101813667A (en) | Method for detecting early-stage mechanical property degradation of material by utilizing nolinear rayleigh wave | |
| CN111442869A (en) | Nonlinear ultrasonic detection method for axial stress of bolt | |
| Li et al. | Inspection of reinforced concrete interface delamination using ultrasonic guided wave non-destructive test technique | |
| CN201637722U (en) | Metallic material early-period fatigue damage nonlinear ultrasonic on-line detection device | |
| Huan et al. | Long-distance structural health monitoring of buried pipes using pitch-catch T (0, 1) wave piezoelectric ring array transducers | |
| CN108802203B (en) | rod-shaped member internal defect positioning method based on multi-mode technology | |
| Ongpeng et al. | Contact and noncontact ultrasonic nondestructive test in reinforced concrete beam | |
| Stepinski | Novel instrument for inspecting rock bolt integrity using ultrasonic guided waves | |
| Li et al. | Stress measurement for steel slender waveguides based on the nonlinear relation between guided wave group velocity and stress | |
| CN101393172A (en) | Non-damage detection for cracks in solid by non-linear resonating sound spectrum method | |
| CN105806944A (en) | Method and device for detecting fatigue damage of cable | |
| Zou et al. | A new approach for field instrumentation in grouted rock bolt monitoring using guided ultrasonic waves | |
| Rizzo et al. | Effect of frequency on the acoustoelastic response of steel bars | |
| CN201653989U (en) | System for testing early mechanical property degradation of material by utilizing non-linear Rayleigh waves | |
| Sciegaj et al. | The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses | |
| CN107894443A (en) | It is a kind of to be used to monitor anchoring elastic piezoelectric ceramics system and monitoring method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |