Bridge diaphragm plate damage early warning method based on sound transmission principle

Abstract

The invention relates to the technical field of diaphragm plate damage early warning, in particular to a bridge diaphragm plate damage early warning method based on the sound transmission principle, and the method comprises the steps: placing a miniature loudspeaker in a leftmost cavity in a steel box girder for sound excitation, and obtaining a sound pressure value in a rightmost cavity through a microphone; multiple frequencies are changed, the first step is repeated, and the microphone obtains sound pressure values after sound transmission of different frequencies; sorting the sound pressure values to respectively obtain sound transmission loss curves of experiments of transmitting sound waves from left to right and from right to left; the sound transmission loss curves in the two different sound transmission directions are compared and analyzed to determine damage early warning of the bridge diaphragm plate; according to the method, the sound transmission loss curves in the two directions are analyzed according to the sound transmission principle to determine whether the bridge diaphragm is damaged or not, and the accuracy of damage early warning of the bridge diaphragm is improved.

Description

Technical Field

[0001] The invention relates to the technical field of diaphragm damage early warning, and in particular to a bridge diaphragm damage early warning method based on the sound transmission principle. Background Art

[0002] Steel box girder structures are widely used in large-span bridges. Under long-term traffic loads, fatigue damage is very likely to occur between the internal diaphragms and U-ribs of steel box girders, resulting in cracks. The location of the cracks is difficult to observe with the naked eye, which can easily lead to safety hazards. The internal diaphragms of steel box girders have similar stiffness, shape, and resonance frequency. Once a diaphragm is damaged and the natural frequency is offset, the existing technology for diaphragm damage detection mostly uses naked eye detection, which has the problems of low efficiency and low detection accuracy.

[0003] Chinese patent application publication number: CN103901111A discloses a non-destructive testing system and method for wind turbine blades. The acoustic emission sensor unit is used to detect the damage signal of the internal deformation and crack extension of the wind turbine blade when the wind turbine blade material is loaded, and transmit the detected signal to the acoustic emission pre-amplification and filtering unit. The acoustic emission pre-amplification and filtering unit is used to amplify and filter the detected signal, and then transmit the amplified and filtered signal to the acoustic emission data acquisition unit. The acoustic emission data acquisition unit collects the signal transmitted by the acoustic emission pre-amplification and filtering unit to generate an acoustic emission signal, and transmits the acoustic emission signal to the data processing and display unit. The data processing and display unit uses a wavelet analysis method to denoise the acoustic emission signal, and uses a wavelet transform to reconstruct the processed signal, and analyzes the reconstructed signal to extract characteristic values ​​and spectra.

[0004] It can be seen that the existing technology has the problem of low accuracy of the control process when issuing damage warnings using the principle of sound transmission, resulting in low accuracy of damage warning judgments. Summary of the invention

[0005] To this end, the present invention provides a bridge diaphragm damage warning method based on the principle of sound transmission, so as to overcome the problem of low accuracy of the control process when issuing damage warnings using the principle of sound transmission in the prior art, resulting in low accuracy of damage warning judgment.

[0006] To achieve the above object, the present invention provides a bridge diaphragm damage early warning method based on the acoustic transmission principle, comprising:

[0007] The micro-speaker is placed in the leftmost chamber inside the steel box girder. The micro-speaker converts the electrical signal into a short-duration pulse sound pressure signal of a fixed frequency to acoustically excite the bridge diaphragm. The sound is transmitted through the steel plate from left to right, and the microphone obtains the sound pressure value in the rightmost chamber.

[0008] The first step is repeated by changing multiple frequencies, and the microphone obtains the sound pressure values ​​after the sound of different frequencies is transmitted;

[0009] Performing qualification judgment on the sound pressure values ​​to select sound pressure values ​​that can be used to obtain a sound transmission loss curve;

[0010] The sound pressure values ​​are sorted to obtain the sound transmission loss curve of the experiment in which the sound wave is transmitted from left to right, and the sound transmission direction is changed to obtain the sound transmission loss curve of the experiment in which the sound wave is transmitted from right to left;

[0011] The sound transmission loss curves of two different sound transmission directions are compared and analyzed, and the damage warning of the bridge diaphragm is determined according to the similarity of the sound transmission loss curves of two different sound transmission directions;

[0012] The adjustment of the bridge diaphragm damage warning process is determined according to the accuracy evaluation value of the bridge diaphragm damage warning.

[0013] Furthermore, when the sound pressure values ​​are judged to be qualified to screen out sound pressure values ​​that can be used to obtain the sound transmission loss curve, a second measurement of the sound pressure value at the frequency point is determined under the condition that the ambient noise value when the microphone obtains the sound pressure value is greater than or equal to the preset ambient noise value.

[0014] Further, when the sound pressure value is judged to be qualified to screen out the sound pressure value that can be used as the sound pressure value for obtaining the sound transmission loss curve, the sound pressure value is determined to be the sound pressure value for obtaining the sound transmission loss curve under the condition that the ambient noise value when the microphone obtains the sound pressure value is less than a preset ambient noise value.

[0015] Furthermore, when it is determined to issue a damage warning for a bridge diaphragm, it is determined to issue a damage warning for the bridge diaphragm under the condition that the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity, or a secondary judgment is performed under the condition that the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity.

[0016] Furthermore, when performing a secondary judgment, it is determined that a damage warning is issued under the condition that the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is less than a preset sound transmission damage value.

[0017] Furthermore, when performing a secondary judgment, it is determined that no damage warning will be issued under the condition that the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is greater than or equal to a preset sound transmission damage value.

[0018] Further, when no damage warning is issued for the bridge diaphragm, the adjustment of the damage warning process for the bridge diaphragm is determined under the condition that the accuracy evaluation value of the damage warning issued for the bridge diaphragm is less than a preset accuracy evaluation value.

[0019] Further, when determining to adjust the damage warning process of the bridge diaphragm, it is determined to adjust the preset similarity with a first adjustment coefficient under the condition that the difference between the accuracy evaluation value of the damage warning for the bridge diaphragm and the preset accuracy evaluation value is less than or equal to the preset difference.

[0020] Further, when determining to adjust the damage warning process of the bridge diaphragm, it is determined to adjust the preset environmental noise value with a second adjustment coefficient under the condition that the difference between the accuracy evaluation value of the damage warning for the bridge diaphragm and the preset accuracy evaluation value is greater than the preset difference.

[0021] Furthermore, the accuracy evaluation value of the damage warning issued to the bridge diaphragm is calculated by the following formula:

[0022]

[0023] Among them, P represents the accuracy evaluation value, T0 represents the preset maintenance and replacement period of the diaphragm, T represents the maintenance and replacement period of the diaphragm, Y represents the frequency of collapse accidents occurring after the non-destructive early warning of the bridge is performed using the present invention, and Y0 represents the preset collapse accident frequency.

[0024] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention determines the eligibility of the sound pressure value obtained by the microphone by analyzing the ambient noise value around the speaker when the speaker is acoustically excited. If the ambient noise value is greater than or equal to the preset ambient noise value, it means that the ambient noise affects the sound pressure value obtained by the microphone during the acoustic excitation, resulting in the sound pressure value obtained by the microphone in different directions. The microphone is misjudged due to the ambient noise. Therefore, when the ambient noise value is greater than or equal to the preset ambient noise value, the sound pressure value obtained is unqualified and needs to be measured again. If the ambient noise value is less than the preset ambient noise value, it is determined that the sound pressure value obtained by the microphone is qualified, and the qualified sound pressure value is used as the sound pressure value for obtaining the sound transmission loss curve. The above method improves the accuracy of drawing the sound transmission loss curve and thus improves the accuracy of the early warning of bridge diaphragm damage.

[0025] Furthermore, the present invention utilizes the characteristic that the flexibility of the diaphragm will not decrease significantly over time to compare and analyze the sound transmission loss curves in two different sound transmission directions. If the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity, it means that there is a damage defect in the bridge diaphragm. If the similarity of the sound transmission loss curves in two different sound transmission directions is greater than or equal to the preset similarity, further damage warning analysis of the bridge diaphragm is performed to avoid the phenomenon that the sound transmission loss curve is greatly different from the sound transmission loss curve when the bridge diaphragm is not damaged due to environmental factors, thereby causing inaccurate damage warning results.

[0026] Furthermore, the present invention further analyzes the result that the similarity of the sound transmission loss curves in two different sound transmission directions is greater than or equal to a preset similarity. If the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is less than the preset sound transmission damage value, it means that the bridge diaphragm in the central cavity is damaged, and a damage warning is issued. The above method avoids the phenomenon that the similarity of the sound transmission loss curves in two directions is greater than or equal to the preset similarity, which causes the damage warning to be judged incorrectly. The above method improves the accuracy of the control of the bridge diaphragm damage warning process.

[0027] Furthermore, the present invention determines the adjustment of the damage warning process of the bridge diaphragm according to the comparison result of the accuracy evaluation value of the damage warning issued by the bridge diaphragm and the preset accuracy evaluation value. The present invention calculates the accuracy evaluation value according to the maintenance and replacement cycle of the bridge diaphragm for which no damage warning is issued and the frequency of collapse accidents occurring after the bridge is issued a non-destructive warning. The phenomenon of increased frequency of bridge collapse due to inaccurate damage warning of the bridge diaphragm is avoided. The above method improves the accuracy of the control of the damage warning of the bridge diaphragm and thus improves the safety of bridge use.

[0028] Furthermore, the present invention determines the adjustment method of the bridge diaphragm damage warning process by comparing the difference between the accuracy evaluation value of the damage warning and the preset accuracy evaluation value with the preset difference. If the difference is less than or equal to the preset difference, it means that the preset similarity of the sound transmission loss curves in the two directions is small, resulting in no damage warning for the damaged bridge diaphragm, and it is determined to increase the preset similarity with the first adjustment coefficient. If the difference is greater than the preset difference, it means that the sound transmission loss curve is not drawn accurately due to the large ambient noise when drawing the sound transmission loss curve, resulting in inaccurate damage warning for the bridge diaphragm, and it is determined to reduce the preset ambient noise value with the second adjustment coefficient. The above method improves the accuracy of drawing the sound transmission loss curve and thus improves the accuracy of the bridge diaphragm damage warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flowchart of a bridge diaphragm damage early warning method based on the acoustic transmission principle according to an embodiment of the present invention;

[0030] Figure 2 A flowchart of determining the eligibility of sound pressure values ​​in a bridge diaphragm damage early warning method based on the sound transmission principle according to an embodiment of the present invention;

[0031] Figure 3 A flowchart for determining a damage warning for a bridge diaphragm damage warning method based on the acoustic transmission principle according to an embodiment of the present invention;

[0032] Figure 4The present invention provides a workflow diagram for determining the adjustment of the process of issuing a damage warning to a bridge according to the bridge diaphragm damage warning method based on the acoustic transmission principle in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0035] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0036] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] See also Figure 1-Figure 4 As shown, Figure 1 This is a flowchart of a bridge diaphragm damage early warning method based on the acoustic transmission principle according to an embodiment of the present invention; Figure 2 A flowchart of determining the eligibility of sound pressure values ​​in a bridge diaphragm damage early warning method based on the sound transmission principle according to an embodiment of the present invention; Figure 3 A flowchart for determining a damage warning for a bridge diaphragm damage warning method based on the acoustic transmission principle according to an embodiment of the present invention; Figure 4 The present invention provides a workflow diagram for determining the adjustment of the process of issuing a damage warning to a bridge according to the bridge diaphragm damage warning method based on the acoustic transmission principle in an embodiment of the present invention.

[0038] The bridge diaphragm damage early warning method based on the acoustic transmission principle in the embodiment of the present invention includes:

[0039] Step S1, placing a micro speaker in the leftmost chamber inside the steel box girder, the micro speaker converts the electrical signal into a short-time pulse sound pressure signal of a fixed frequency, acoustically excites the bridge diaphragm, the sound is transmitted through the steel plate from left to right, and the microphone obtains the sound pressure value in the rightmost chamber;

[0040] Step S2, changing multiple frequencies and repeating the first step, the microphone acquires the sound pressure values ​​after the sound of different frequencies is transmitted;

[0041] Step S3, performing qualification determination on the sound pressure values ​​to select sound pressure values ​​that can be used to obtain a sound transmission loss curve;

[0042] Step S4, sorting the sound pressure values ​​to obtain a sound transmission loss curve of an experiment in which sound waves are transmitted from left to right, and changing the sound transmission direction to obtain a sound transmission loss curve of an experiment in which sound waves are transmitted from right to left;

[0043] Step S5, comparing and analyzing the sound transmission loss curves of two different sound transmission directions, and determining whether to issue a damage warning to the bridge diaphragm according to the similarity of the sound transmission loss curves of the two different sound transmission directions;

[0044] Step S6: Determine the adjustment of the bridge diaphragm damage warning process according to the accuracy evaluation value of the bridge diaphragm damage warning.

[0045] The multiple frequencies described in the embodiment of the present invention include but are not limited to “100 Hz, 200 Hz, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 700 Hz, 800 Hz, 900 Hz, and 1000 Hz”.

[0046] Specifically, when the sound pressure value is judged as qualified to screen out the sound pressure value that can be used to obtain the sound transmission loss curve, the qualification of the sound pressure value is determined according to the comparison result of the ambient noise value A when the microphone obtains the sound pressure value and the preset ambient noise value A0;

[0047] When A≥A0, it is determined that the sound pressure value is unqualified;

[0048] When A<A0, it is determined that the sound pressure value is qualified;

[0049] The preset value of the ambient noise value A0 is three fifths of the sound pressure value, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0050] The environmental noise value in the embodiment of the present invention includes but is not limited to the sound pressure level value of the environmental noise.

[0051] Specifically, when the sound pressure value is unqualified, determining to perform a second measurement on the sound pressure value of the frequency point;

[0052] When the sound pressure value is qualified, it is determined to use the sound pressure value as the sound pressure value for obtaining the sound transmission loss curve.

[0053] The frequency point described in the embodiment of the present invention is the frequency at which the micro-speaker converts the electrical signal into a short-time pulse sound pressure signal of a fixed frequency to acoustically excite the bridge diaphragm when the ambient noise value is greater than or equal to the preset ambient noise value.

[0054] Specifically, the present invention determines the eligibility of the sound pressure value obtained by the microphone by analyzing the ambient noise value around the speaker when the speaker is acoustically excited. If the ambient noise value is greater than or equal to the preset ambient noise value, it means that the ambient noise affects the sound pressure value obtained by the microphone during acoustic excitation, resulting in the sound pressure value obtained by the microphone in different directions. The microphone is misjudged due to the ambient noise. Therefore, when the ambient noise value is greater than or equal to the preset ambient noise value, the sound pressure value obtained is unqualified and needs to be measured again. If the ambient noise value is less than the preset ambient noise value, it is determined that the sound pressure value obtained by the microphone is qualified, and the qualified sound pressure value is used as the sound pressure value for obtaining the sound transmission loss curve. The above method improves the accuracy of drawing the sound transmission loss curve and thus improves the accuracy of early warning of bridge diaphragm damage.

[0055] Specifically, when it is determined to issue a damage warning for a bridge diaphragm, it is determined to issue a damage warning for the bridge diaphragm according to a comparison result of the similarity M of the sound transmission loss curves in two different sound transmission directions with a preset similarity M0;

[0056] When M<M0, it is determined to issue a damage warning to the bridge diaphragm;

[0057] When M≥M0, it is determined to perform a secondary judgment;

[0058] Among them, the preset similarity M0 is the historical average value of the similarity of the sound transmission loss curves in two directions when no damage warning is issued for the bridge diaphragm, but the above value is not limited to this, and technical personnel in this field can also adjust the value according to actual needs.

[0059] Specifically, the present invention utilizes the characteristic that the flexibility of the diaphragm will not decrease significantly over time to compare and analyze the sound transmission loss curves in two different sound transmission directions. If the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity, it means that there is a damage defect in the bridge diaphragm. If the similarity of the sound transmission loss curves in two different sound transmission directions is greater than or equal to the preset similarity, further damage warning analysis of the bridge diaphragm is performed to avoid the phenomenon that the sound transmission loss curve is greatly different from the sound transmission loss curve when the bridge diaphragm is not damaged due to environmental factors, thereby causing inaccurate damage warning results.

[0060] Specifically, when a secondary judgment is made on the damage warning issued by the bridge diaphragm, it is determined that the bridge diaphragm issues a damage warning according to the comparison result of the sound transmission damage value N transmitted from the central cavity of the steel beam box to the next cavity and the preset sound transmission damage value N0;

[0061] When N<N0, it is determined to issue a damage warning to the bridge diaphragm;

[0062] When N≥N0, it is determined that no damage warning is issued for the bridge diaphragm;

[0063] Among them, the preset sound transmission damage value N0 is four-fifths of the sound transmission damage value of a single lossless bridge diaphragm, but the above value is not limited to this, and technical personnel in this field can also adjust the value according to actual needs.

[0064] In the embodiment of the present invention, the similarity of the sound transmission loss curves of the two different sound transmission directions includes but is not limited to "curve shape similarity, curve numerical similarity and curve length similarity". The central chamber of the steel beam box is the chamber in the middle position among all the chambers of the steel beam box, and the sound transmission damage value is preferably the ratio of the front and rear sound power passing through the diaphragm.

[0065] Specifically, the present invention further analyzes the result that the similarity of the sound transmission loss curves in two different sound transmission directions is greater than or equal to the preset similarity. If the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is less than the preset sound transmission damage value, it means that the bridge diaphragm in the central cavity is damaged, and a damage warning is issued. The above method avoids the phenomenon that the similarity of the sound transmission loss curves in two directions is greater than or equal to the preset similarity, which causes the damage warning to be judged incorrectly. The above method improves the accuracy of the control of the bridge diaphragm damage warning process.

[0066] Specifically, when a damage warning is issued for the bridge diaphragm, a thermal imaging method is used to determine the damage location and perform repairs and replacements.

[0067] Specifically, when no damage warning is issued for the bridge diaphragm, the adjustment of the damage warning process for the bridge diaphragm is determined according to the comparison result of the accuracy evaluation value P for issuing the damage warning for the bridge diaphragm and the preset accuracy evaluation value P0;

[0068] When P≥P0, it is determined that the bridge diaphragm damage warning process is not adjusted;

[0069] When P<P0, determining to adjust the bridge diaphragm damage warning process;

[0070] Among them, the preset accuracy evaluation value P0 is the historical average value of the accuracy evaluation value of the bridge diaphragm damage warning, but the above value is not limited to this, and technical personnel in this field can also adjust the value according to actual needs.

[0071] Specifically, the accuracy evaluation value P of the damage warning issued to the bridge diaphragm is calculated by the following formula and is set:

[0072]

[0073] Wherein, T0 represents the preset maintenance and replacement period of the diaphragm, T represents the maintenance and replacement period of the diaphragm, Y represents the frequency of collapse accidents occurring after the non-destructive early warning of the bridge is performed using the present invention, and Y0 represents the preset collapse accident frequency.

[0074] In the embodiment of the present invention, the value of the preset maintenance and replacement period is the historical average value of the maintenance and replacement period of the bridge diaphragm, and the value of the preset collapse accident frequency is the ratio of the number of bridge collapses to the bridge usage time, but the above values ​​are not limited to this, and technical personnel in this field can also adjust the values ​​according to actual needs.

[0075] Specifically, the present invention determines the adjustment of the damage warning process for the bridge diaphragm according to the comparison result of the accuracy evaluation value of the damage warning issued for the bridge diaphragm and the preset accuracy evaluation value. The present invention calculates the accuracy evaluation value according to the maintenance and replacement cycle of the bridge diaphragm for which no damage warning is issued and the frequency of collapse accidents that occur after the bridge is issued a non-destructive warning. The phenomenon of increased frequency of bridge collapse due to inaccurate damage warning for the bridge diaphragm is avoided. The above method improves the accuracy of the damage warning control for the bridge diaphragm and thus improves the safety of bridge use.

[0076] Specifically, when it is determined to adjust the bridge diaphragm damage warning process, the adjustment method of the bridge diaphragm damage warning process is determined according to the comparison result between the difference △P of the accuracy evaluation value of the damage warning issued to the bridge diaphragm and the preset accuracy evaluation value and the preset difference △P0;

[0077] When △P≤△P0, determining to adjust the bridge diaphragm damage early warning process in a first adjustment manner;

[0078] When ΔP>ΔP0, it is determined to adjust the bridge diaphragm damage early warning process in a second adjustment manner;

[0079] The preset difference △P0 is set to one tenth of the preset accuracy evaluation value, but the above value is not limited thereto, and those skilled in the art may also adjust the value according to actual needs.

[0080] Specifically, when the bridge diaphragm damage warning process is adjusted in a first adjustment manner, it is determined that the preset similarity is adjusted by a first adjustment coefficient K1;

[0081] When the bridge diaphragm damage warning process is adjusted in the second adjustment mode, it is determined that the preset environmental noise value is adjusted by the second adjustment coefficient K2.

[0082] Specifically, the first adjustment coefficient K1 is calculated and set by the following formula:

[0083]

[0084] The second adjustment coefficient K2 is calculated and set by the following formula:

[0085]

[0086] The adjusted preset similarity is set to M0'=K1×M0;

[0087] The adjusted preset environmental noise value is set to A0'=K2×A0.

[0088] Specifically, the present invention determines the adjustment method of the bridge diaphragm damage warning process by comparing the difference between the accuracy evaluation value of the damage warning and the preset accuracy evaluation value with the preset difference. If the difference is less than or equal to the preset difference, it means that the preset similarity of the sound transmission loss curves in the two directions is small, resulting in no damage warning for the damaged bridge diaphragm, and it is determined to increase the preset similarity with the first adjustment coefficient. If the difference is greater than the preset difference, it means that the sound transmission loss curve is not drawn accurately due to the large ambient noise when drawing the sound transmission loss curve, resulting in inaccurate damage warning for the bridge diaphragm, and it is determined to reduce the preset ambient noise value with the second adjustment coefficient. The above method improves the accuracy of drawing the sound transmission loss curve and thus improves the accuracy of the bridge diaphragm damage warning.

[0089] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bridge diaphragm damage early warning method based on the principle of acoustic transmission, characterized in that: include: The micro-speaker is placed in the leftmost chamber inside the steel box girder. The micro-speaker converts the electrical signal into a short-duration pulse sound pressure signal of a fixed frequency to acoustically excite the bridge diaphragm. The sound is transmitted through the steel plate from left to right, and the microphone obtains the sound pressure value in the rightmost chamber. The first step is repeated by changing multiple frequencies, and the microphone obtains the sound pressure values ​​after the sound of different frequencies is transmitted; Performing qualification judgment on the sound pressure values ​​to select sound pressure values ​​that can be used to obtain a sound transmission loss curve; The sound pressure values ​​are sorted to obtain the sound transmission loss curve of the experiment in which the sound wave is transmitted from left to right, and the sound transmission direction is changed to obtain the sound transmission loss curve of the experiment in which the sound wave is transmitted from right to left; The sound transmission loss curves of two different sound transmission directions are compared and analyzed, and the damage warning of the bridge diaphragm is determined according to the similarity of the sound transmission loss curves of two different sound transmission directions; The adjustment of the bridge diaphragm damage warning process is determined according to the accuracy evaluation value of the bridge diaphragm damage warning.

2. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 1 is characterized in that: When the sound pressure values ​​are qualified to screen out the sound pressure values ​​that can be used to obtain the sound transmission loss curve, it is determined to perform a secondary measurement of the sound pressure value at the frequency point under the condition that the ambient noise value when the microphone obtains the sound pressure value is greater than or equal to the preset ambient noise value.

3. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 1 is characterized in that: When the sound pressure value is judged as qualified to screen out the sound pressure value that can be used as the sound pressure value for obtaining the sound transmission loss curve, the sound pressure value is determined to be used as the sound pressure value for obtaining the sound transmission loss curve under the condition that the ambient noise value when the microphone obtains the sound pressure value is less than the preset ambient noise value.

4. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 1 is characterized in that: When it is determined to issue a damage warning for a bridge diaphragm, it is determined to issue a damage warning for the bridge diaphragm under the condition that the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity, or a secondary judgment is performed under the condition that the similarity of the sound transmission loss curves in two different sound transmission directions is less than a preset similarity.

5. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 4 is characterized in that: When performing a secondary judgment, it is determined that a damage warning is issued under the condition that the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is less than a preset sound transmission damage value.

6. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 4 is characterized in that: When performing a secondary judgment, it is determined that no damage warning is issued under the condition that the sound transmission damage value transmitted from the central cavity of the steel beam box to the next cavity is greater than or equal to the preset sound transmission damage value.

7. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 6 is characterized in that: When no damage warning is issued for the bridge diaphragm, it is determined that the damage warning process for the bridge diaphragm is adjusted under the condition that the accuracy evaluation value of the damage warning issued for the bridge diaphragm is less than a preset accuracy evaluation value.

8. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 7 is characterized in that: When determining to adjust the bridge diaphragm damage warning process, it is determined to adjust the preset similarity with a first adjustment coefficient under the condition that the difference between the accuracy evaluation value of the damage warning for the bridge diaphragm and the preset accuracy evaluation value is less than or equal to the preset difference.

9. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 7 is characterized in that: When determining to adjust the damage warning process of the bridge diaphragm, it is determined to adjust the preset environmental noise value with a second adjustment coefficient under the condition that the difference between the accuracy evaluation value of the damage warning for the bridge diaphragm and the preset accuracy evaluation value is greater than the preset difference.

10. The bridge diaphragm damage early warning method based on the acoustic transmission principle according to claim 7 is characterized in that: The accuracy evaluation value of the damage warning issued to the bridge diaphragm is calculated by the following formula: Wherein, P represents the accuracy evaluation value, T0 represents the preset maintenance and replacement period of the diaphragm, T represents the maintenance and replacement period of the diaphragm, Y represents the frequency of collapse accidents occurring after the non-destructive early warning of the bridge is performed using the present invention, and Y0 represents the preset collapse accident frequency.

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