CN119618452B - A preload electromagnetic ultrasonic sound time recognition monitoring method - Google Patents
A preload electromagnetic ultrasonic sound time recognition monitoring method Download PDFInfo
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- CN119618452B CN119618452B CN202510165524.4A CN202510165524A CN119618452B CN 119618452 B CN119618452 B CN 119618452B CN 202510165524 A CN202510165524 A CN 202510165524A CN 119618452 B CN119618452 B CN 119618452B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
- G01L5/246—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed using acoustic waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/14—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object using acoustic emission techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor
- G01N29/4454—Signal recognition, e.g. specific values or portions, signal events, signatures
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- Acoustics & Sound (AREA)
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- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
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Abstract
本发明公开了一种预紧力电磁超声声时识别监测方法，包括下述步骤：在螺栓处于无预紧力的状态下，通过电磁超声预紧力测量系统从起始波后沿开始搜索回波包络，通过峰值算法识别到螺栓无预紧力时间段最高连续的j个周期回波包络；将螺栓无预紧力时间段的超声声时存储为t0；对螺栓施加预紧力，通过电磁超声预紧力测量系统从起始波后沿开始搜索回波包络，通过峰值算法识别到螺栓施加预紧力时间段最高连续的j个周期回波包络，将螺栓施加预紧力时间段的超声声时存储为t1；根据公式F=KΔt，得到F=K(t1‑t0)，计算出准确的渡越时间Δt，并精准计算出螺栓预紧力F。本发明能够自动重新识别和计算回波包络的超声声时，提高螺栓预紧力测量的准确性和稳定性。
The present invention discloses a pre-tightening force electromagnetic ultrasonic acoustic time recognition and monitoring method, comprising the following steps: when the bolt is in a state of no pre-tightening force, searching the echo envelope from the trailing edge of the starting wave by the electromagnetic ultrasonic pre-tightening force measurement system, identifying the highest continuous j-cycle echo envelope in the time period of no pre-tightening force of the bolt by the peak algorithm; storing the ultrasonic acoustic time of the time period of no pre-tightening force of the bolt as t 0 ; applying pre-tightening force to the bolt, searching the echo envelope from the trailing edge of the starting wave by the electromagnetic ultrasonic pre-tightening force measurement system, identifying the highest continuous j-cycle echo envelope in the time period of applying pre-tightening force of the bolt by the peak algorithm, storing the ultrasonic acoustic time of the time period of applying pre-tightening force of the bolt as t 1 ; according to the formula F=KΔt, F=K(t 1 ‑t 0 ) is obtained, the accurate transit time Δt is calculated, and the bolt pre-tightening force F is accurately calculated. The present invention can automatically re-recognize and calculate the ultrasonic acoustic time of the echo envelope, and improve the accuracy and stability of bolt pre-tightening force measurement.
Description
Technical Field
The invention relates to the technical field of pretightening force measurement electromagnetic ultrasonic, in particular to a pretightening force electromagnetic ultrasonic sound time identification monitoring method.
Background
The wind power blades, the tower, the engine room and the main shaft are used as important parts of the wind turbine generator, and all are connected by adopting high-strength bolts. Whether the pretightening force of the high-strength bolt meets the construction requirement is an important monitoring link for the installation and maintenance of the wind turbine generator, and whether the wind turbine generator can reliably and safely run for a long time is related.
According to the acoustic elastic effect, when the sound wave propagates in the solid, the propagation speed has a linear relation with the stress state of the solid medium, and along with the change of the stress applied to the solid, the sound velocity of the sound wave also changes correspondingly. As is known from hooke's law, the stress σ in a solid is proportional to the strain ε, i.e., σ=ε ε, where σ is the material stress (force per unit area), E is the elastic modulus (young's modulus), and ε is the strain (deformation per unit length). When a preload is applied to the bolt, the applied preload is the stress in the bolt, and the applied preload is different, so that the propagation speed of ultrasonic waves in the bolt is also different, and the corresponding sound is also different.
The mathematical function relation between the transit time and the bolt pre-tightening force is obtained by monitoring the sound time change of the ultrasonic wave in the bolt under different pre-tightening forces, so that the magnitude of the bolt pre-tightening force is indirectly measured. The mathematical functional relation between the transit time of ultrasonic waves in a bolt and the bolt pretightening force is F=KDeltat=K (t 1-t0), wherein F is the bolt pretightening force, K is the test calibration sound elasticity coefficient, deltat is the change of sound when the bolt pretightens (namely the transit time of ultrasonic waves in the bolt), t 1 is the sound when the bolt pretightens, and t 0 is the sound when the bolt pretightens. Therefore, it is very critical to accurately identify and monitor the bolt without pretension and when the pretension is applied.
The echo of the electromagnetic ultrasonic measuring bolt is generally a multi-period echo envelope, the amplitude height of each period of the echo envelope is changed due to different pretightening force or bolt difference, and when the period position corresponding to the highest amplitude is changed, the highest amplitude position of the traditional ultrasonic monitoring echo envelope is adopted to measure ultrasonic sound, and the measured ultrasonic sound is at least deviated by 1 period. If the ultrasonic frequency of the measuring bolt is 2.5MHz, the vibration period of the ultrasonic wave is 400 nanoseconds, the deviation of the measured ultrasonic sound is at least 400 nanoseconds, which is far greater than the ultrasonic sound time change of tens of nanoseconds or even a few nanoseconds caused by the pretightening force change, and the pretightening force measurement accuracy is seriously affected.
Disclosure of Invention
The invention aims to solve the problem of providing a method for identifying and monitoring pretightening force electromagnetic ultrasonic sound, which can improve the accuracy and stability of bolt pretightening force measurement when automatically identifying and calculating ultrasonic sound of echo envelope.
In order to solve the technical problems, the invention adopts the following technical scheme:
The method for recognizing and monitoring the pretightening force electromagnetic ultrasonic sound is characterized by comprising the following steps of:
(1) The electromagnetic ultrasonic transverse and longitudinal wave probe is placed on the end face of the non-stressed bolt, the echo envelope is searched from the initial wave back edge through the electromagnetic ultrasonic pre-tightening force measuring system under the state that the bolt is in the non-pre-tightening force state, and the j continuous cycle echo envelopes which are the highest in the non-pre-tightening force time period of the bolt are identified through the peak value algorithm;
(2) Recording the peak acoustic time of the j periodic echo envelopes identified in the step (1), sequencing the peak acoustic time of the j periodic echo envelopes according to the time sequence, and storing the peak acoustic time of the j periodic echo envelopes as t 01、t02、……、t0j, wherein j is equal to or larger than 1;
(3) Selecting the Nth peak sound from the peak sounds of the j periodic echo envelopes in the step (2) as the appointed monitoring ultrasonic sound, wherein N is larger than or equal to 1;
(4) Storing ultrasonic sound of the bolt without pretightening force in a time period as t 0;
(5) Applying pre-tightening force to the bolt, searching echo envelopes from the initial wave back edge through an electromagnetic ultrasonic pre-tightening force measuring system, and identifying j continuous cycle echo envelopes which are the highest in the time period of applying the pre-tightening force to the bolt through a peak value algorithm;
(6) Recording the peak acoustic time of the j periodic echo envelopes identified in the step (5), and sequencing the peak acoustic time of the j periodic echo envelopes according to the time sequence, wherein the peak acoustic time of the j periodic echo envelopes is stored as t 11、t12、……、t1j, and j is larger than or equal to 1;
(7) Selecting the Nth peak sound from the peak sounds of the j periodic echo envelopes in the step (6) as the appointed monitoring ultrasonic sound, wherein N is larger than or equal to 1;
(8) Storing ultrasonic sound of a bolt in a pre-tightening force time period as t 1;
(9) According to a formula F=K delta t, wherein F is bolt pretightening force, K is test calibration acoustic elasticity coefficient, delta t is transit time of ultrasonic waves in the bolt, F=K (t 1-t0) is obtained, accurate transit time delta t is calculated, and bolt pretightening force F is accurately calculated;
(10) And (3) when the bolt pretightening force is different, re-identifying and calculating ultrasonic sound t 1 of the bolt pretightening force applying time period according to the steps (5) - (8), storing, and re-calculating accurate transit time delta t and bolt pretightening force F according to the step (9).
In the steps (2) and (6), j+.1 in the j cycle echo envelopes. The identified j periodic echo envelopes can be expanded to 3 or more than 3, the data of a plurality of periodic echo envelopes can be cross-validated, the characteristics of the echo envelopes can be more accurately captured, and the measurement error is reduced.
The reason for the difference in the bolt pretightening force in the step (10) is caused by inaccurate bolt construction or change of the bolt after long-term operation.
In a preferred embodiment, in the steps (1) and (5), the peak of the highest continuous j periodic echo envelopes is selected, and then the peak of the periodic echo envelope continuous with the peak of the highest periodic echo envelope is selected forward or backward.
In a preferred embodiment, in the steps (3) and (7), the ultrasonic sound to be monitored is designated as a peak sound of any one cycle of the echo envelopes of j cycles. When the peak sound of any period is selected as the ultrasonic sound for appointed monitoring, the complexity of the algorithm can be simplified, and the processing speed can be improved.
Of course, in the above steps (3) and (7), the ultrasonic sound to be monitored is designated as zero crossing sound of any one cycle of the echo envelopes of j cycles. The change of zero crossing point sound is relatively stable, and particularly when the pretightening force change is small, the measurement error is small, so that the error caused by the change of the wave crest position can be reduced, and the accuracy of the measurement result is improved.
Compared with the prior art, the invention has the following advantages:
according to the method for identifying and monitoring the pretightening force electromagnetic ultrasonic sound, the accurate transit time delta t of the ultrasonic wave in the bolt is calculated by respectively recording the ultrasonic sound time t 0 when the bolt does not have pretightening force and the ultrasonic sound time t 1 when the bolt applies pretightening force, so that the problem of sound time deviation caused by the change of the period corresponding to the highest amplitude of the ultrasonic echo envelope can be solved when the ultrasonic sound of the echo envelope is automatically identified and calculated, and the accuracy and the stability of bolt pretightening force measurement are improved.
Drawings
FIG. 1 is a schematic diagram of t 1、t0 of the present invention when the bolt has ultrasonic sound with or without a pretension period in example 1;
FIG. 2 is a schematic diagram of t 1、t0 when the bolt of example 2 of the present invention has ultrasonic sound in the pretension period;
Fig. 3 is a schematic diagram of t 1、t0 when the bolt of embodiment 3 of the present invention has ultrasonic sound in the pretension period.
Detailed Description
The invention is described in detail below with reference to the drawings and the specific embodiments.
Embodiment 1, as shown in fig. 1, the method for identifying and monitoring the pretightening force electromagnetic ultrasonic sound in the embodiment includes the following steps:
(1) The method comprises the steps of placing an electromagnetic ultrasonic transverse and longitudinal wave probe on the end face of a non-stressed bolt, searching echo envelopes from the initial rear edge through an electromagnetic ultrasonic pre-tightening force measuring system under the condition that the bolt is in a non-pre-tightening force state, and identifying the highest continuous 2-period echo envelopes in the non-pre-tightening force time period of the bolt through a peak value algorithm;
(2) Recording the wave crest sounds of the 2 periodic echo envelopes identified in the step (1), sequencing the wave crest sounds according to the time sequence, and storing the wave crest sounds of the 2 periodic echo envelopes as t 01、t02;
(3) Selecting the 1 st peak sound time t 01 from the peak sounds of the 2-period echo envelopes in the step (2) as the ultrasonic sound time for appointed monitoring;
(4) Storing ultrasonic sound of the bolt without pretightening force in a time period as t 0;
(5) Applying pre-tightening force to the bolt, searching echo envelopes from the initial wave back edge through an electromagnetic ultrasonic pre-tightening force measuring system, and identifying the 2 continuous period echo envelopes which are the highest in the time period of applying the pre-tightening force to the bolt through a peak value algorithm;
(6) Recording the wave crest sounds of the 2-period echo envelopes identified in the step (5), sequencing the wave crest sounds according to the time sequence, and storing the wave crest sounds of the 2-period echo envelopes as t 11、t12;
(7) Selecting the 1 st peak sound time t 11 from the peak sounds of the 2-period echo envelopes in the step (6) as the ultrasonic sound time for appointed monitoring;
(8) Storing ultrasonic sound of a bolt in a pre-tightening force time period as t 1;
(9) According to a formula F=K delta t, wherein F is bolt pretightening force, K is test calibration acoustic elasticity coefficient, delta t is transit time of ultrasonic waves in the bolt, F=K (t 1-t0)=K(t11-t01) is obtained, accurate transit time delta t is calculated, and bolt pretightening force F is accurately calculated;
(10) And (3) when the bolt pretightening force is different, re-identifying and calculating ultrasonic sound t 1 of the bolt pretightening force applying time period according to the steps (5) - (8), storing, and re-calculating accurate transit time delta t and bolt pretightening force F according to the step (9).
The reason for the difference in the bolt pretightening force in the step (10) is caused by inaccurate bolt construction or change of the bolt after long-term operation.
In the steps (1) and (5), the highest 2 continuous periodic echo envelopes are that after the peak of the highest periodic echo envelope is selected, the peak of the periodic echo envelope continuous with the peak is selected forward or backward.
Of course, in the steps (3) and (7), the ultrasonic sound to be monitored may be specified as the peak sound of any one period of the echo envelope of 2 periods. When the peak sound of any period is selected as the ultrasonic sound for appointed monitoring, the complexity of the algorithm can be simplified, and the processing speed can be improved.
In embodiment 2, as shown in fig. 2, the difference between the method for identifying and monitoring the pretightening force electromagnetic ultrasonic sound in this embodiment and embodiment 1 is that:
(1) Under the condition that the bolt is in a state without pretightening force, searching an echo envelope from the initial rear edge through an electromagnetic ultrasonic pretightening force measuring system, and identifying the highest continuous 3-period echo envelopes in the bolt pretightening force-free time period through a peak value algorithm;
(2) Recording the wave crest sounds of the 3-period echo envelopes identified in the step (1), sequencing the wave crest sounds according to the time sequence, and storing the wave crest sounds of the 3-period echo envelopes as t 01、t02、t03;
(3) Selecting the 2 nd peak sound time t 02 from the peak sound time of the 3-period echo envelope in the step (2) as the appointed monitoring ultrasonic sound time;
(4) Storing ultrasonic sound of the bolt without pretightening force in a time period as t 0;
(5) Applying pre-tightening force to the bolt, searching echo envelopes from the initial wave back edge through an electromagnetic ultrasonic pre-tightening force measuring system, and identifying the 2 continuous period echo envelopes which are the highest in the time period of applying the pre-tightening force to the bolt through a peak value algorithm;
(6) Recording the wave crest sounds of the 3-period echo envelopes identified in the step (5), sequencing the wave crest sounds according to the time sequence, and storing the wave crest sounds of the 3-period echo envelopes as t 11、t12、t13;
(7) Selecting the 2 nd peak sound time t 12 from the peak sound time of the 3-period echo envelope in the step (6) as the ultrasonic sound time of appointed monitoring;
(8) Storing ultrasonic sound of a bolt in a pre-tightening force time period as t 1;
(9) According to a formula F=K delta t, wherein F is bolt pretightening force, K is test calibration acoustic elasticity coefficient, delta t is transit time of ultrasonic waves in the bolt, F=K (t 1-t0)=K(t12-t02) is obtained, accurate transit time delta t is calculated, and bolt pretightening force F is accurately calculated;
(10) And (3) when the bolt pretightening force is different, re-identifying and calculating ultrasonic sound t 1 of the bolt pretightening force applying time period according to the steps (5) - (8), storing, and re-calculating accurate transit time delta t and bolt pretightening force F according to the step (9).
The identified j periodic echo envelopes can be expanded to 3 or more than 3, the data of a plurality of periodic echo envelopes can be cross-validated, the characteristics of the echo envelopes can be more accurately captured, and the measurement error is reduced.
Embodiment 3 as shown in fig. 3, the difference between the pretensioning electromagnetic ultrasonic sound time identification monitoring method in this embodiment and embodiment 1 is that in steps (3) and (7), the ultrasonic sound time to be monitored is specified to be zero crossing sound of any one cycle in the 2 cycle echo envelopes. The change of zero crossing point sound is relatively stable, and particularly when the pretightening force change is small, the measurement error is small, so that the error caused by the change of the wave crest position can be reduced, and the accuracy of the measurement result is improved.
In addition, it should be noted that, in the specific embodiments described in the present specification, names of various parts and the like may be different, and all equivalent or simple changes of the structures, features and principles described in the conception of the present invention are included in the protection scope of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the invention as defined in the accompanying claims.
Claims (3)
1. The method for recognizing and monitoring the pretightening force electromagnetic ultrasonic sound is characterized by comprising the following steps of:
(1) The electromagnetic ultrasonic transverse and longitudinal wave probe is placed on the end face of the non-stressed bolt, the echo envelope is searched from the initial wave back edge through the electromagnetic ultrasonic pre-tightening force measuring system under the state that the bolt is in the non-pre-tightening force state, and the j continuous cycle echo envelopes which are the highest in the non-pre-tightening force time period of the bolt are identified through the peak value algorithm;
(2) Recording the peak acoustic time of the j periodic echo envelopes identified in the step (1), sequencing the peak acoustic time of the j periodic echo envelopes according to the time sequence, and storing the peak acoustic time of the j periodic echo envelopes as t 01、t02、……、t0j, wherein j is equal to or larger than 1;
(3) Selecting the Nth peak sound from the peak sounds of the j periodic echo envelopes in the step (2) as the appointed monitoring ultrasonic sound, wherein N is larger than or equal to 1;
(4) Storing ultrasonic sound of the bolt without pretightening force in a time period as t 0;
(5) Applying pre-tightening force to the bolt, searching echo envelopes from the initial wave back edge through an electromagnetic ultrasonic pre-tightening force measuring system, and identifying j continuous cycle echo envelopes which are the highest in the time period of applying the pre-tightening force to the bolt through a peak value algorithm;
(6) Recording the peak acoustic time of the j periodic echo envelopes identified in the step (5), and sequencing the peak acoustic time of the j periodic echo envelopes according to the time sequence, wherein the peak acoustic time of the j periodic echo envelopes is stored as t 11、t12、……、t1j, and j is larger than or equal to 1;
(7) Selecting the Nth peak sound from the peak sounds of the j periodic echo envelopes in the step (6) as the appointed monitoring ultrasonic sound, wherein N is larger than or equal to 1;
(8) Storing ultrasonic sound of a bolt in a pre-tightening force time period as t 1;
(9) According to a formula F=K delta t, wherein F is bolt pretightening force, K is test calibration acoustic elasticity coefficient, delta t is transit time of ultrasonic waves in the bolt, F=K (t 1- t0) is obtained, accurate transit time delta t is calculated, and bolt pretightening force F is accurately calculated;
(10) And (3) when the bolt pretightening force is different, re-identifying and calculating ultrasonic sound t 1 of the bolt pretightening force applying time period according to the steps (5) - (8), storing, and re-calculating accurate transit time delta t and bolt pretightening force F according to the step (9).
2. The method for recognizing and monitoring the pretightening force electromagnetic ultrasonic sound according to claim 1, wherein in the steps (1) and (5), the peak of the highest continuous j periodic echo envelopes is selected, and then the peak of the periodic echo envelope continuous with the peak of the highest periodic echo envelope is selected forwards or backwards.
3. The method for recognizing and monitoring the pretightening force electromagnetic ultrasonic sound according to claim 1, wherein the ultrasonic sound to be monitored is designated as the peak sound of any one cycle of the echo envelope of j cycles in the steps (3) and (7).
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