Indirect bridge damage measurement method and system based on dual-axle vehicle

Abstract

The present invention provides an indirect bridge damage measurement method and system based on a dual-axle vehicle, which relates to the field of bridge detection technology, and includes: obtaining the vertical displacement of the front axle and the vertical displacement of the rear axle when the vehicle passes through each bridge contact point, further obtaining the vertical displacement and rotational displacement of the vehicle at each bridge contact point, obtaining the displacement response of the front axle when passing the bridge contact point and the displacement response of the rear axle when passing the bridge contact point based on the vertical displacement and rotational displacement of the vehicle at each bridge contact point, and then obtaining the displacement response residual of each bridge contact point; performing wavelet transformation on each displacement response residual to obtain a wavelet coefficient map; processing the wavelet coefficient map based on the variational mode decomposition method to obtain a bridge damage parameter map; determining the bridge damage position based on the bridge damage parameter map. The present invention overcomes the influence of surface roughness and noise, and indirectly measures and evaluates the damage position and relative size of the bridge using only the response data of a single bridge-crossing vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge detection, and in particular to an indirect bridge damage measurement method and system based on a double-axle vehicle. Background Art

[0002] In recent years, identifying bridge information from vehicle vibration response has become a rapidly developing method. In this theory, the vehicle not only acts as an external load to excite the bridge, but also acts as a signal receiver. This method is called indirect measurement, also known as vehicle scanning method (VSM). Compared with direct measurement, this method of indirectly identifying bridge modal characteristics by installing a single or a few sensors on the bridge-passing vehicle is more attractive because it does not require the sensors to be installed on the bridge in advance and is economical and convenient. Once this technology was proposed, it has received widespread attention. Many studies have successfully used vehicles to indirectly measure the modal parameters of bridges such as frequency, damping, and vibration mode. Related field tests have also verified the effectiveness of the method in extracting bridge frequencies and modal vibration modes.

[0003] Furthermore, the potential of VSM method in the field of damage detection has also received increasing attention. However, this bridge detection method based on vehicle body signals is inevitably affected by vehicle body vibration, while the bridge-related information should be paid attention to. For this reason, the vehicle-bridge contact point response theory was proposed, which is essentially a bridge response without the interference of vehicle body vibration. In many studies, this method has been shown to have better performance in detecting and locating bridge damage than directly using vehicle body response. However, the bridge detection method based on contact point response is greatly affected by the roughness of the bridge deck, and the derivation of the contact point acceleration response under vehicle body damping involves differential operation of the measurement signal, which may amplify the influence of measurement noise. Summary of the invention

[0004] The purpose of the present invention is to provide an indirect bridge damage measurement method and system based on a dual-axle vehicle, which overcomes the influence of surface roughness and noise and indirectly measures and evaluates the damage location and relative size of the bridge using only the response data of a single bridge-crossing vehicle.

[0005] An indirect bridge damage measurement method based on a dual-axle vehicle, the dual-axle vehicle having a front axle and a rear axle, comprising:

[0006] S1, obtaining a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point;

[0007] S2, obtaining a first vehicle vertical displacement and a first vehicle rotational displacement when the front axle passes through a bridge contact point based on the first front axle vertical displacement and the first rear axle vertical displacement; obtaining a second vehicle vertical displacement and a second vehicle rotational displacement when the rear axle passes through a bridge contact point based on the second front axle vertical displacement and the second rear axle vertical displacement;

[0008] The first vehicle vertical displacement expression is: ; The first vehicle rotation displacement expression is: ; Where: is the moment when the front axle passes the bridge contact point, is the vertical displacement of the first vehicle, is the distance between the front and rear axles, is the vertical displacement of the first front axle, is the vertical displacement of the first rear axle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the first vehicle rotation displacement;

[0009] S3, obtaining a first displacement response of the bridge contact point when the front axle passes through the bridge contact point based on the first vehicle vertical displacement and the first vehicle rotational displacement; obtaining a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point based on the second vehicle vertical displacement and the second vehicle rotational displacement; S4, obtaining a displacement response residual of the bridge contact point based on the first displacement response and the second displacement response;

[0010] S5, repeatedly executing S1-S4 to obtain the displacement response residual of each bridge contact point;

[0011] S6, performing wavelet transform on the displacement response residual of each bridge contact point to obtain a wavelet coefficient map; processing the wavelet coefficient map based on variational mode decomposition method to obtain a bridge damage parameter map;

[0012] S7, determining a bridge damage location based on the bridge damage parameter map.

[0013] Optionally, the displacement response residual of each bridge contact point is subjected to wavelet transformation based on Gaus3 wavelet as a basis function to obtain the wavelet coefficient map.

[0014] Alternatively, the displacement response residual expression of the bridge contact point is: ; Where: represents the derivation, , , is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, is the displacement response residual of the bridge contact point, is the suspension damping of the rear axle, is the spring stiffness of the front axle, is the spring stiffness of the rear axle, is the speed of the two-axle vehicle, is the moment when the rear axle passes the bridge contact point, is the sampling time interval between adjacent bridge contact points, is the mass of the two-axle vehicle, is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, The present invention provides an indirect bridge damage measurement system based on a double-axle vehicle, wherein the double-axle vehicle has a front axle and a rear axle, and comprises:

[0015] A data acquisition module, used to acquire a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point;

[0016] a displacement module, configured to obtain a first vehicle vertical displacement and a first vehicle rotational displacement when the front axle passes through a bridge contact point based on the first front axle vertical displacement and the first rear axle vertical displacement; and to obtain a second vehicle vertical displacement and a second vehicle rotational displacement when the rear axle passes through a bridge contact point based on the second front axle vertical displacement and the second rear axle vertical displacement;

[0017] The first vehicle vertical displacement expression is: ;

[0018] The first vehicle rotation displacement expression is: ; Where: is the moment when the front axle passes the bridge contact point, is the vertical displacement of the first vehicle, is the distance between the front and rear axles, is the vertical displacement of the first front axle, is the vertical displacement of the first rear axle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is a first vehicle rotation displacement; a displacement response module, used to obtain a first displacement response of the bridge contact point when the front axle passes through the bridge contact point based on the first vehicle vertical displacement and the first vehicle rotation displacement; and to obtain a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point based on the second vehicle vertical displacement and the second vehicle rotation displacement;

[0019] a response residual module, configured to obtain a displacement response residual of a bridge contact point based on the first displacement response and the second displacement response;

[0020] Repeat the execution module, repeatedly execute the data acquisition module to the response residual module, and obtain the displacement response residual of each bridge contact point;

[0021] A damage parameter module is used to perform wavelet transform on the displacement response residual of each bridge contact point to obtain a wavelet coefficient map; the wavelet coefficient map is processed based on a variational mode decomposition method to obtain a bridge damage parameter map;

[0022] A damage detection module is used to determine the bridge damage location based on the bridge damage parameter map.

[0023] Optionally, the displacement response residual of each bridge contact point is subjected to wavelet transformation based on Gaus3 wavelet as a basis function to obtain the wavelet coefficient map.

[0024] Alternatively, the displacement response residual expression of the bridge contact point is: ; Where: represents the derivation, , , is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, is the displacement response residual of the bridge contact point, is the suspension damping of the rear axle, is the spring stiffness of the front axle, is the spring stiffness of the rear axle, is the speed of the two-axle vehicle, is the moment when the rear axle passes the bridge contact point, is the sampling time interval between adjacent bridge contact points, is the mass of the two-axle vehicle, is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, is the rotational displacement of the second vehicle.

[0025] The effects of the present invention are as follows:

[0026] The indirect bridge damage measurement method based on a dual-axle vehicle of the present invention can effectively reduce the influence of road roughness on damage identification effect, can effectively reduce the interference of high-frequency irrelevant components generated by noise on damage positioning, can use a small number of vehicle body sensors and a single bridge crossing test vehicle to effectively evaluate bridge damage, and can maintain the applicability and accuracy of damage identification when facing different vehicle speeds, damage conditions, noise intensity, and road roughness levels, and has strong robustness to different parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of the indirect bridge damage measurement method based on a dual-axle vehicle of the present invention;

[0028] Figure 2 is a schematic diagram of the adopted vehicle-bridge coupling vibration analysis model;

[0029] Figure 3 is a schematic diagram of the displacement response of the bridge contact points of the front and rear axles considering measurement noise and road roughness;

[0030] Figure 4 is the continuous wavelet transform coefficient map of the displacement response of the front and rear axle bridge contact points;

[0031] Figure 5 is the wavelet coefficient graph of the displacement response residuals at 0%, 1%, 3% and 5% noise level intensities;

[0032] Figure 6 is the damage parameter DI at 0%, 1%, 3% and 5% noise level intensity;

[0033] Figure 7 It is the DI under 30% damage level of unit 10, unit 16 and unit 21 respectively;

[0034] Figure 8 It is to consider the DI of unit 16 when it is damaged by 0%, 20%, 30% and 40% respectively;

[0035] Fig. 9 The DI is considered as follows: no damage, 30% damage to unit 10 and unit 16, 30% damage to unit 16 and unit 21, and 30% damage to unit 10 and unit 21;

[0036] Fig.10 It is to consider the DI of unit 10 and unit 21 under different damage degrees respectively;

[0037] Fig.11 is the DI considering the damage condition of unit 16 at 2m / s, 4m / s, 6m / s and 8m / s respectively;

[0038] Fig.12 It is a schematic diagram of bridge road surface irregularities of Class B, C, D and E;

[0039] Fig.13 It is the DI of the damage condition of unit 16 under road surface irregularities of levels B, C, D, and E;

[0040] Fig.14 It is the DI of the damage conditions of units 10 and 21 under road irregularities of levels B, C, D, and E. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0042] Figure 1 FIG. 1 is a flow chart of the indirect bridge damage measurement method based on a dual-axle vehicle of the present invention. Figure 1 As shown, the present invention provides an indirect bridge damage measurement method based on a double-axle vehicle, the double-axle vehicle having a front axle and a rear axle, which includes:

[0043] S1, obtaining a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point. Specifically, a linear displacement sensor is arranged at the center of mass of the vehicle, and the first front axle vertical displacement, the first rear axle vertical displacement, the second front axle vertical displacement, and the second rear axle vertical displacement are obtained based on the linear displacement sensor.

[0044] S2, based on the first front axle vertical displacement and the first rear axle vertical displacement, obtain the first vehicle vertical displacement and the first vehicle rotational displacement when the front axle passes the bridge contact point; based on the second front axle vertical displacement and the second rear axle vertical displacement, obtain the second vehicle vertical displacement and the second vehicle rotational displacement when the rear axle passes the bridge contact point.

[0045] The first vehicle vertical displacement expression is: .

[0046] The first vehicle rotation displacement expression is: .

[0047] Where: is the moment when the front axle passes the bridge contact point, is the vertical displacement of the first vehicle, is the distance between the front and rear axles, is the vertical displacement of the first front axle, is the vertical displacement of the first rear axle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, S3, based on the first vehicle vertical displacement and the first vehicle rotational displacement, obtain a first displacement response of the bridge contact point when the front axle passes through the bridge contact point; based on the second vehicle vertical displacement and the second vehicle rotational displacement, obtain a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point.

[0048] S4, obtaining a displacement response residual of the bridge contact point based on the first displacement response and the second displacement response.

[0049] Preferably, the displacement response residual expression of the bridge contact point is: ; Where: represents the derivation, , is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, is the displacement response residual of the bridge contact point, is the suspension damping of the rear axle, is the spring stiffness of the front axle, is the spring stiffness of the rear axle, is the speed of the two-axle vehicle, is the moment when the rear axle passes the bridge contact point, is the sampling time interval between adjacent bridge contact points, is the mass of the two-axle vehicle, is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, is the rotational displacement of the second vehicle.

[0050] S5, repeat S1-S4 to obtain the displacement response residual of each bridge contact point.

[0051] S6, performing wavelet transform on the displacement response residuals of each bridge contact point to obtain a wavelet coefficient map; processing the wavelet coefficient map based on the variational mode decomposition method to obtain a bridge damage parameter map. Specifically, performing wavelet transform on the displacement response residuals of each bridge contact point based on the Gaus3 wavelet as the basis function to obtain a wavelet coefficient map.

[0052] S7, determining a bridge damage location based on the bridge damage parameter map.

[0053] Specifically, the present invention adopts Figure 2 The vehicle-bridge coupled vibration analysis model shown is used to illustrate the method of the present invention. Figure 2 middle, is the surface roughness of the bridge contact point at the rear axle, is the surface roughness of the bridge contact point at the front axle.

[0054] The vertical balance equation of a two-axle vehicle is: .

[0055] The rotational balance equation for a two-axle vehicle is: .

[0056] Consider the roughness of the road surface of Class A and Gaussian white noise with a noise level of 1%. Since the actual bridge contact point response cannot be measured directly, the original data of the calculation comes from the vehicle sensor, so we add noise to the vertical and angular responses of the vehicle body involved in the calculation. The bridge is divided into 30 finite element units, and the beam unit damage is set at 2 / 3 of the bridge span. The damage simulation adopts the stiffness reduction method, the damage degree is 30%, and the time component is 0.001s. The vehicle-bridge parameters are shown in Tables 1 and 2.

[0057] Table 1 Bridge parameters

[0058] parameter symbol unit Numeric span L m 30 Mass per unit length M t / m 4 Young's modulus E Gpa 21 Moment of inertia of area I <![CDATA[m 4 ]]> 0.48 First natural frequency <![CDATA[f1]]> Hz 2.77 Second natural frequency <![CDATA[f2]]> Hz 11.08

[0059] Table 2 Vehicle parameters

[0060] parameter symbol unit Numeric Body mass <![CDATA[M v ]]> t 5 Front axle and rear axle stiffness <![CDATA[k1、k2]]> N / m <![CDATA[5.0×10 3 ]]> Front axle and rear axle damping <![CDATA[c1、c2]]> N·s / m <![CDATA[1.0×10 3 ]]> Moment of Inertia Jv <![CDATA[kg·m 2 ]]> <![CDATA[3.5×10 3 ]]> Axle spacing d m 1.5 Vertical frequency <![CDATA[f r ]]> Hz 2.25 Rotation frequency <![CDATA[f h ]]> Hz 2.02

[0061] The contact point displacement response of the front and rear axles of the vehicle is calculated as follows: Figure 3 As shown in Figure 2. x / L represents the normalized position of the axle on the bridge relative to the span, that is, when x / L is 0 or 1, the axle is located at the leftmost and rightmost sides of the bridge, respectively.

[0062] Under the combined effect of road roughness and noise, unfavorable parameters produce a certain degree of high-frequency pollution components in the contact point displacement response signal, which accounts for a small proportion of the signal. Obviously, the damage location cannot be effectively analyzed only through this response. Further, the displacement response residual of the contact point is calculated and the wavelet coefficients at multiple scales are calculated by continuous wavelet transform. In view of the excellent performance of Gaussian wavelet in the field of damage identification, Gaus3 wavelet is used as the basis function with a center frequency of 0.3Hz. The scale range is selected as 1000, and the wavelet coefficients of the contact point response residual are calculated as follows: Figure 4 shown. Figure 4 It shows that the damage can be located and analyzed by the peak value of the wavelet coefficient, because the wavelet coefficients in the damageless area remain stable, while the local extreme values ​​caused by the boundary effect have different signs from the extreme values ​​of the wavelet coefficients caused by the damage. It is worth noting that although the damage location at a 1% noise level can be determined by peak picking, the wavelet coefficients in the entire time domain also have high-frequency pollution components caused by this parameter. Therefore, further analysis of the impact of noise is necessary. Taking the noise level intensity as 0%, 1%, 3% and 5%, and keeping the other parameters unchanged, the wavelet coefficient point line graph is plotted as shown below. Figure 5 shown.

[0063] Obviously, as the noise level increases, the amplitude of the contamination component in the intact area gradually increases and approaches the extreme value at the damaged location. Figure 5 The residual wavelet coefficients of the contact point displacement response under medium noise level are used for variational mode decomposition and reconstruction, with a penalty factor of 4000 and a convergence tolerance of 1×10-6 , the decomposition mode number is taken as 5th order, and the intrinsic mode function IMF5 is calculated, that is, the damage parameter DI is as follows Figure 6 shown.

[0064] from Figure 6 It can be seen that the damage parameter DI obtained by the present invention can effectively reduce the interference of noise in the vehicle body signal on identification. At a noise level of 5%, the location of the damage can still be determined by the extreme value of the damage index. In addition, the influence of the road surface roughness is also successfully eliminated by the displacement response residual of the contact point.

[0065] Furthermore, in the single damage condition analysis, the vulnerable parts of the bridge, namely, one-third, one-half, and two-thirds of the bridge span, were firstly set with 30% damage levels for No. 10, No. 16, and No. 21, respectively, and compared with the non-destructive condition. The road surface roughness and noise level were considered to be Class A and 1%, respectively. The damage parameter DI was obtained as follows: Figure 7 Then, the multiple damage levels at the specific damage location are further analyzed. Unit 16 is taken for analysis with no damage and 20%, 30%, and 40% damage levels, and the other parameters remain unchanged, as shown in Figure 8 shown.

[0066] In reality, there are often bridge structures with multiple damages, so it is necessary to identify and analyze multiple damages of the structure. Set the damage of units 10 and 16 to 30%, the damage of units 16 and 21 to 30%, and the damage of units 10 and 21 to 30%, and calculate the damage index results as follows: Fig. 9 As shown. It can be seen that for the above double damage conditions, the damage position can still be determined by the peak picking method and the same damage degree is effectively verified by the corresponding parameter extreme value. Naturally, the damage of unit 10 and unit 21 under the double damage condition of the structure with different damage degrees is analyzed, as shown in Fig.10 As shown. Obviously, when the bridge has structural damages at different locations and with different degrees of damage at the same time, the proposed damage index can still accurately locate the damage location and judge the relative size of the damage degree. While considering the influence of adverse factors such as noise and road surface unevenness, the present invention can still effectively evaluate the damage of single damage and multiple damage conditions.

[0067] Vehicle speed is an important parameter that affects the damage identification effect because it determines the amount of response data that can be used. In the vehicle speed impact analysis, four driving speeds of 8m / s, 6m / s, 4m / s and 2m / s were set, and the damage parameter DI of unit 16 in the mid-span under the 30% damage condition was calculated as follows: Fig.11 Analysis Fig.11It can be seen that the damage position of the bridge at different vehicle speeds can be located and analyzed by calculating the DI extreme value. It is worth noting that with the increase of vehicle speed, the boundary effect of the damage parameter under the analysis scale is also increasing, and the fluctuation range of the wavelet coefficient caused by damage is widening, that is, the time domain resolution is also decreasing. Therefore, if conditions permit, a lower test vehicle speed should be adopted for a more comprehensive and accurate structural damage assessment.

[0068] The roughness of the road surface is a major factor that interferes with the indirect measurement method for modal scanning and damage identification of the structure. The road roughness of level A can be removed by the method of the present invention. However, more road roughness levels have not been considered, and there is no shortage of poor road conditions in actual projects. In the following road roughness impact analysis, the impact of road surface roughness at higher levels will be analyzed. The road surface roughness of levels B, C, D, and E is generated by the standard. Fig.12 As shown. Further, the single damage condition of 30% damage degree of unit 16 and the multiple damage conditions of 30% damage degree of unit 10 and unit 21 under different road roughness are analyzed, and the other parameters remain unchanged. Fig.13 and Fig.14 The results show that the damage positions of single-damage and multi-damage conditions can be judged by peak picking according to the method of the present invention, even under the condition of E-level road roughness. As the road condition deteriorates, the index fluctuation amplitude in the intact area gradually increases, but the DI at the damage position still shows an extreme value in the entire time domain.

[0069] Figure 2 In the diagram, Beam is a bridge. Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 and Fig.11 In the above equation, damagelocation indicates the damage location. Fig.12 , Fig.13 and Fig.14 In the figure, Class indicates the road roughness grade.

[0070] The present invention also provides an indirect bridge damage measurement system based on a double-axle vehicle, wherein the double-axle vehicle has a front axle and a rear axle, and comprises:

[0071] The data acquisition module is used to acquire a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point.

[0072] A displacement module is used to obtain a first vehicle vertical displacement and a first vehicle rotational displacement when the front axle passes through a bridge contact point based on a first front axle vertical displacement and a first rear axle vertical displacement; and to obtain a second vehicle vertical displacement and a second vehicle rotational displacement when the rear axle passes through a bridge contact point based on a second front axle vertical displacement and a second rear axle vertical displacement.

[0073] The first vehicle vertical displacement expression is: The first vehicle rotation displacement expression is: Where: is the moment when the front axle passes the bridge contact point, is the vertical displacement of the first vehicle, is the distance between the front and rear axles, is the vertical displacement of the first front axle, is the vertical displacement of the first rear axle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, is the first vehicle rotation displacement.

[0074] The displacement response module is used to obtain a first displacement response of the bridge contact point when the front axle passes through the bridge contact point based on the first vehicle vertical displacement and the first vehicle rotational displacement; and to obtain a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point based on the second vehicle vertical displacement and the second vehicle rotational displacement.

[0075] The response residual module is used to obtain the displacement response residual of the bridge contact point based on the first displacement response and the second displacement response.

[0076] Repeat the execution module, repeatedly execute the data acquisition module to the response residual module, and obtain the displacement response residual of each bridge contact point.

[0077] Preferably, the displacement response residual expression of the bridge contact point is: ; Where: represents the derivation, , , is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, is the displacement response residual of the bridge contact point, is the suspension damping of the rear axle, is the spring stiffness of the front axle, is the spring stiffness of the rear axle, is the speed of the two-axle vehicle, is the moment when the rear axle passes the bridge contact point, is the sampling time interval between adjacent bridge contact points, is the mass of the two-axle vehicle, is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, is the rotational displacement of the second vehicle.

[0078] The damage parameter module is used to perform wavelet transform on the displacement response residuals of each bridge contact point to obtain a wavelet coefficient map; the wavelet coefficient map is processed based on the variational mode decomposition method to obtain a bridge damage parameter map. Specifically, the displacement response residuals of each bridge contact point are transformed by wavelet transform based on the Gaus3 wavelet as the basis function to obtain a wavelet coefficient map.

[0079] The damage detection module is used to determine the bridge damage location based on the bridge damage parameter map.

[0080] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An indirect bridge damage measurement method based on a double-axle vehicle, the double-axle vehicle having a front axle and a rear axle, characterized in that: It includes: S1, obtaining a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point; S2, obtaining a first vehicle vertical displacement and a first vehicle rotational displacement when the front axle passes through a bridge contact point based on the first front axle vertical displacement and the first rear axle vertical displacement; obtaining a second vehicle vertical displacement and a second vehicle rotational displacement when the rear axle passes through a bridge contact point based on the second front axle vertical displacement and the second rear axle vertical displacement; The first vehicle vertical displacement expression is: The first vehicle rotation displacement expression is: Where: t is the time when the front axle passes the bridge contact point, y v (t) is the first vehicle vertical displacement, d is the distance between the front axle and the rear axle, y1(t) is the first front axle vertical displacement, y2(t) is the first rear axle vertical displacement, d1 is the horizontal distance from the front axle to the center of mass of the dual-axle vehicle, d2 is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, θ v (t) is the first vehicle rotation displacement; S3, obtaining a first displacement response of a bridge contact point when the front axle passes through the bridge contact point based on the first vehicle vertical displacement and the first vehicle rotational displacement; Obtaining a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point based on the second vehicle vertical displacement and the second vehicle rotational displacement; S4, obtaining a displacement response residual of a bridge contact point based on the first displacement response and the second displacement response; S5, repeatedly executing S1-S4 to obtain the displacement response residual of each bridge contact point; S6, performing wavelet transform on the displacement response residual of each bridge contact point to obtain a wavelet coefficient map; The wavelet coefficient map is processed based on the variational mode decomposition method to obtain a bridge damage parameter map; S7, determining a bridge damage location based on the bridge damage parameter map.

2. The indirect bridge damage measurement method based on a dual-axle vehicle according to claim 1 is characterized in that: The displacement response residuals of each bridge contact point are subjected to wavelet transform based on Gaus3 wavelet as the basis function to obtain the wavelet coefficient map.

3. The indirect bridge damage measurement method based on a dual-axle vehicle according to claim 1 is characterized in that: The residual expression of the displacement response of the bridge contact point is: In the formula: · represents the derivative, u1(t) is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, uc is the displacement response residual of the bridge contact point, c2 is the suspension damping of the rear axle, k1 is the spring stiffness of the front axle, k2 is the spring stiffness of the rear axle, v is the speed of the dual-axle vehicle, is the moment when the rear axle passes the bridge contact point, Δt is the sampling time interval between adjacent bridge contact points, M v is the mass of the two-axle vehicle, J v is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, is the rotational displacement of the second vehicle.

4. An indirect bridge damage measurement system based on a double-axle vehicle, the double-axle vehicle having a front axle and a rear axle, characterized in that: It includes: A data acquisition module, used to acquire a first front axle vertical displacement and a first rear axle vertical displacement when the front axle passes through a bridge contact point, and a second front axle vertical displacement and a second rear axle vertical displacement when the rear axle passes through a bridge contact point; a displacement module, configured to obtain a first vehicle vertical displacement and a first vehicle rotational displacement when the front axle passes through a bridge contact point based on the first front axle vertical displacement and the first rear axle vertical displacement; and to obtain a second vehicle vertical displacement and a second vehicle rotational displacement when the rear axle passes through a bridge contact point based on the second front axle vertical displacement and the second rear axle vertical displacement; The first vehicle vertical displacement expression is: The first vehicle rotation displacement expression is: Where: t is the time when the front axle passes the bridge contact point, y v (t) is the first vehicle vertical displacement, d is the distance between the front axle and the rear axle, y1(t) is the first front axle vertical displacement, y2(t) is the first rear axle vertical displacement, d1 is the horizontal distance from the front axle to the center of mass of the dual-axle vehicle, d2 is the horizontal distance from the rear axle to the center of mass of the dual-axle vehicle, θ v (t) is the first vehicle rotation displacement; a displacement response module, configured to obtain a first displacement response of a bridge contact point when the front axle passes through the bridge contact point based on the first vehicle vertical displacement and the first vehicle rotational displacement; and obtain a second displacement response of the bridge contact point when the rear axle passes through the bridge contact point based on the second vehicle vertical displacement and the second vehicle rotational displacement; a response residual module, configured to obtain a displacement response residual of a bridge contact point based on the first displacement response and the second displacement response; Repeat the execution module, repeatedly execute the data acquisition module to the response residual module, and obtain the displacement response residual of each bridge contact point; A damage parameter module is used to perform wavelet transform on the displacement response residual of each bridge contact point to obtain a wavelet coefficient map; The wavelet coefficient map is processed based on the variational mode decomposition method to obtain a bridge damage parameter map; A damage detection module is used to determine the bridge damage location based on the bridge damage parameter map.

5. The indirect bridge damage measurement system based on a dual-axle vehicle according to claim 4 is characterized in that: The displacement response residuals of each bridge contact point are subjected to wavelet transform based on Gaus3 wavelet as the basis function to obtain the wavelet coefficient map.

6. The indirect bridge damage measurement system based on a dual-axle vehicle according to claim 4 is characterized in that: The residual expression of the displacement response of the bridge contact point is: In the formula: · represents the derivative, u1(t) is the first displacement response of the bridge contact point, is the second displacement response of the bridge contact point, uc is the displacement response residual of the bridge contact point, c2 is the suspension damping of the rear axle, k1 is the spring stiffness of the front axle, k2 is the spring stiffness of the rear axle, v is the speed of the dual-axle vehicle, is the moment when the rear axle passes the bridge contact point, Δt is the sampling time interval between adjacent bridge contact points, M v is the mass of the two-axle vehicle, J v is the moment of inertia of the two-axle vehicle, is the vertical displacement of the second vehicle, is the rotational displacement of the second vehicle.

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