A method for compiling load spectrum of main bearing of tunnel boring machine

Abstract

The present invention provides a method for compiling a load spectrum of a main bearing of a tunnel boring machine. By detecting the pressure of a telescopic oil cylinder, the original load time history of the main bearing axial force and overturning moment is calculated, and the original load time history of the main bearing radial force is obtained by multiplying the gravity of the structural part with the engineering coefficient; and then the load spectrum of the main bearing under actual working conditions is obtained through processes such as rain flow counting method processing, load distribution model establishment, load classification processing, and load action times calculation. The present invention solves the problem that the three loads of axial force, radial force, and overturning moment on the main bearing under actual working conditions are difficult to extract. The load spectrum finally obtained is simple in form and equivalent to the effect of the original load time history, and can be used as a reliable input condition for main bearing design verification, theoretical analysis, and working condition testing.

Description

Technical Field

[0001] The invention relates to the technical field of main bearings of tunnel boring machines, and in particular to a method for compiling a load spectrum of a main bearing of a tunnel boring machine. Background Art

[0002] The roadheader is a large-scale tunnel construction equipment that integrates multiple disciplines such as mechanics, optics, hydraulics, and electricity. During the tunnel construction process, it can simultaneously complete factory operations such as tunnel excavation, support, slag removal, and guidance. It has the advantages of high construction efficiency, small surrounding rock disturbance, and safe and reliable construction process. It is called the "king of construction machinery" and is widely used in large-scale engineering construction such as railway tunnels, highway tunnels, and urban subways. The main bearing is a key component of the roadheader and the "heart" of the roadheader. Once it fails, the roadheader will be shut down for a long time or even scrapped, causing huge economic losses. At the same time, the main bearing of the roadheader operates under high thrust, large eccentric load, large torque, high impact, and strong time-varying load, resulting in extremely high reliability requirements.

[0003] In view of this, it is necessary to obtain rigorous and reliable load spectrum data as input conditions for main bearing design verification, theoretical analysis, and working condition tests, to ensure that the designed main bearings have the ability to operate safely and reliably. However, due to the extremely harsh actual operating conditions of the main bearings of the tunnel boring machine, and the main bearings are installed inside the main drive closed structure, it is difficult to arrange the sensors and acquisition systems required to directly collect the actual working condition loads of the main bearings. During the operation of the main bearing, it is simultaneously subjected to three loads: axial force, radial force, and overturning moment. The data obtained by conventional detection methods are difficult to accurately decouple into detailed information of the three loads. In addition, the actual working condition loads of the main bearings collected are very complex, the amount of data is huge, the processing difficulty is extremely high, and there is a lack of processing methods to effectively integrate the actual working condition loads. Therefore, the industry has not yet been able to obtain the load spectrum of the main bearings of the tunnel boring machine under actual working conditions.

[0004] In summary, there is an urgent need for a method for compiling a load spectrum of a main bearing of a tunnel boring machine to solve the problems existing in the prior art. Summary of the invention

[0005] The purpose of the present invention is to provide a method for compiling a load spectrum of a main bearing of a tunnel boring machine, aiming to solve the problem of obtaining the load spectrum of the main bearing of the tunnel boring machine under actual working conditions. The specific technical solution is as follows:

[0006] A method for compiling a load spectrum of a main bearing of a tunnel boring machine comprises the following steps:

[0007] Step S1: measuring the pressure of n telescopic cylinders arranged along the circumferential direction at the rear end of the main bearing, and calculating the original load time history of the axial force and overturning moment exerted on the main bearing;

[0008] Step S2: Obtain the gravity of the front end structural component of the main bearing, multiply the gravity of the structural component by the engineering coefficient to obtain the radial force original load time history of the main bearing, and ensure that the data volume of the radial force original load time history is the same as the data volume of the axial force and overturning moment original load time history;

[0009] Step S3: Based on the rain flow counting method, the load amplitude, load mean and the number of times the three original loads act are obtained respectively;

[0010] Step S4: using a statistical distribution model to fit the acquired load amplitude and its action times, load mean and its action times, respectively, to obtain the load amplitude and load mean distribution models of the three original loads;

[0011] Step S5: Based on the obtained load amplitude distribution model, a load with an occurrence probability of P is selected on the right side of the distribution model as the amplitude maximum value, and the amplitude maximum value is multiplied by the ratio coefficients of multiple levels to obtain a multi-level amplitude;

[0012] Step S6: Superimpose the multi-level amplitudes of the three original loads on the corresponding load mean values ​​to obtain the multi-level loads, then calculate the number of times each level of load acts based on the load amplitude distribution model, and calculate the probability distribution of each level of load acts based on the number of times each level of load acts, so as to obtain the multi-level load spectrum of the three original loads under the actual working conditions of the main bearing.

[0013] Preferably, in the above technical solution, in step S1, the axial force and overturning moment of the main bearing are calculated according to equations 1) to 4):

[0014]

[0015]

[0016]

[0017]

[0018] Among them, F a is the axial force on the main bearing, M is the overturning moment on the main bearing, F i is the pressure applied by the i-th telescopic cylinder, n is the number of telescopic cylinders, l ix , l iy are the distances from the i-th telescopic cylinder to the y-axis and x-axis, M x 、M y It is the torque generated by the telescopic cylinder on the main bearing in the x-axis and y-axis directions.

[0019] Preferably in the above technical solution, the engineering coefficient is 1+k, and k is a random number ranging from 0 to 1.

[0020] Preferably, in the above technical solution, in step S3, MATLAB programming is used to process the original load time history of the axial force, radial force and overturning moment, and the load amplitude, load amplitude action times, load mean and load mean action times of the three original loads are obtained respectively.

[0021] Preferably, in the above technical solution, in step S4, the load amplitude and the number of load amplitude actions are fitted using a three-parameter Weibull distribution, and the load mean and the number of load mean actions are fitted using a normal distribution.

[0022] In the above technical solution, the three-parameter Weibull distribution model is preferably as shown in Formula 5), ​​and the normal distribution model is as shown in Formula 6).

[0023]

[0024]

[0025] Among them, f(x a ) is the amplitude x a The probability density function of f(x m ) is the mean x m is the probability density function of , σ is the shape parameter, μ is the location parameter, π is the circumference of a circle, and e is the base of the natural logarithm.

[0026] In the above technical solution, preferably, in step S5, the multi-level amplitude is calculated according to formula 7)-formula 8),

[0027]

[0028] x ai =K i ·x amax Formula 8),

[0029] Among them, x amax is the maximum amplitude, x ai is the i-th level amplitude, K i is the ratio coefficient of the i-th level.

[0030] In the above technical solution, preferably, there are m levels of ratio coefficients, and the ratio coefficients from level 1 to level m gradually decrease.

[0031] Preferably, in the above technical solution, in step S6, based on the load amplitude distribution model, the number of times the first-level load acts is set to 1, and the number of times another m-1-level load acts is calculated according to formula 9)-formula 10),

[0032]

[0033] nj =N j -N j-1 Formula 10),

[0034] In formula 9), N i represents the cumulative number of load actions from level 1 to the i-th level, i is a natural number from 1 to m; in formula 10), n j Indicates the number of times the j-th level load acts, N j It indicates the cumulative number of times the load from level 1 to level j acts, where j is a natural number from 2 to m.

[0035] In the above technical solution, preferably, in step S6, the probability distribution of load action at each level is calculated according to formula 11),

[0036]

[0037] Among them, P i represents the probability of the i-th level load acting.

[0038] The application of the technical solution of the present invention has the following beneficial effects:

[0039] The method of the present invention effectively solves the technical problems that it is difficult to arrange sensors and acquisition systems directly used to collect the actual working load of the main bearing inside the main drive closed structure, and that conventional detection means are difficult to accurately decouple the acquired data into three load detailed information. The present invention fully analyzes the axial load-bearing characteristics of the main bearing, measures the pressure of the telescopic cylinder, and obtains accurate and reliable original load-time history of the main bearing axial force and overturning moment through calculation. In addition, based on the radial load-bearing characteristics of the main bearing, the original load-time history of the main bearing radial force is obtained by multiplying the gravity of the front end structural part of the main bearing by the engineering coefficient; it effectively solves the problem of the difficulty in extracting the three loads of axial force, radial force and overturning moment on the main bearing under actual working conditions.

[0040] However, the original load time history of the main bearing under actual working conditions obtained only by the above method is disordered and changes dramatically, which is difficult to be directly used for main bearing design verification, theoretical analysis, working condition test, etc. At the same time, the actual working condition load of the main bearing collected and obtained is very complex, the amount of data is huge, and the processing difficulty is extremely high. Conventional processing methods are difficult to effectively integrate the original load history into a simple, accurate and reliable load spectrum.

[0041] Therefore, the present invention uses the rain flow counting method to process the original load time history, and obtains the load characteristics in the original load time history, that is, the load amplitude, load mean and the number of times the two act in the original load time history. Then, through the process of load distribution model establishment, load classification processing and load action number calculation, the load spectrum under the actual working condition of the main bearing is obtained. The load spectrum finally obtained is simple in form and equivalent to the effect of the original load time history, which can be used as a reliable input condition for the main bearing design verification, theoretical analysis and working condition test.

[0042] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 It is a schematic diagram of the relationship between the main bearing and other related parts in the tunnel boring machine;

[0045] Figure 2 is a flow chart of the preparation method of the present invention;

[0046] Figure 3 This is a schematic diagram of the force decomposition method of the telescopic cylinder;

[0047] Among them, 1. Cutter disc and flange structural parts, 2. Main bearing, 3. Telescopic cylinder. DETAILED DESCRIPTION

[0048] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are provided. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0050] Embodiment 1:

[0051] See also Figure 1 , Figure 1The diagram shows a typical three-row cylindrical roller turntable bearing, with the Z direction being the tunneling direction of the tunnel boring machine. The rear end of the tunnel boring machine main bearing 2 is provided with n telescopic cylinders 3 along the circumferential direction, and the front end is provided with a cutter head and flange structure 1. The main bearing 2 is subjected to an axial force F at the same time during operation. a , overturning moment M and radial force F r . According to the force balance relationship, the axial force on the main bearing in the axial direction always maintains a force balance with the telescopic cylinder connected to the rear end of the main bearing. Therefore, by measuring the pressure of each telescopic cylinder 3, the axial force and overturning moment on the main bearing can be obtained; the force on the main bearing in the radial direction is mainly the gravity of the front structural parts, that is, the radial force of the main bearing can be obtained according to the gravity of the cutter head and flange structural parts 1. Among them, the pressure of the telescopic cylinder can be measured by a monitoring system, such as a pressure sensor.

[0052] Therefore, this embodiment provides a method for compiling a load spectrum of a main bearing of a tunnel boring machine, such as Figure 2-Figure 3 As shown, the following steps are included:

[0053] Step S1: measuring the pressure of n telescopic cylinders arranged along the circumferential direction at the rear end of the main bearing, and calculating the original load time history of the axial force and overturning moment exerted on the main bearing;

[0054] Preferably, the force decomposition method of the telescopic cylinder is as follows Figure 3 As shown, in step S1, the axial force and overturning moment of the main bearing are calculated according to equations 1) to 4):

[0055]

[0056]

[0057]

[0058]

[0059] Among them, F a is the axial force on the main bearing, M is the overturning moment on the main bearing, F i is the pressure applied by the i-th telescopic cylinder, n is the number of telescopic cylinders, l ix , l iy are the distances from the i-th telescopic cylinder to the y-axis and x-axis, M x 、M y It is the torque generated by the telescopic cylinder on the main bearing in the x-axis and y-axis directions.

[0060] Step S2: Obtain the gravity of the structural parts at the front end of the main bearing, multiply the gravity of the structural parts by the engineering coefficient to obtain the original load time history of the radial force of the main bearing, and ensure that the data volume of the original load time history of the radial force is the same as the data volume of the original load time history of the axial force and the overturning moment; preferably, the engineering coefficient is 1+k, and k is a random number ranging from 0 to 1.

[0061] Step S3: Based on the rain flow counting method, the load amplitude, load mean and the number of times the three original loads act are obtained respectively;

[0062] Preferably, in step S3 of this embodiment, MATLAB programming is used to process the original load time history of the axial force, radial force and overturning moment, and the load amplitude, load amplitude action times, load mean and load mean action times of the three original loads are obtained respectively.

[0063] Step S4: using a statistical distribution model to fit the acquired load amplitude and its action times, load mean and its action times, respectively, to obtain the load amplitude and load mean distribution models of the three original loads;

[0064] Specifically, the load amplitude and the number of load amplitude actions are fitted using a three-parameter Weibull distribution, and the load mean and the number of load mean actions are fitted using a normal distribution. The three-parameter Weibull distribution model is shown in Formula 5), ​​and the normal distribution model is shown in Formula 6):

[0065]

[0066]

[0067] Among them, f(x a ) is the amplitude x a The probability density function of f(x m ) is the mean x m is the probability density function of , σ is the shape parameter, μ is the location parameter, π is the circumference of a circle, and e is the base of the natural logarithm.

[0068] Step S5: Based on the obtained load amplitude distribution model, a load with an occurrence probability of P is selected on the right side of the distribution model as the amplitude maximum value, and the amplitude maximum value is multiplied by the ratio coefficients of multiple levels to obtain a multi-level amplitude;

[0069] In step S5, the multi-level amplitude is calculated according to equation 7)-equation 8):

[0070]

[0071] x ai =K i ·xamax Formula 8),

[0072] Among them, x amax is the maximum amplitude, x ai is the i-th level amplitude, K i is the ratio coefficient of the i-th level.

[0073] Preferably, in this embodiment, there are m levels of ratio coefficients, and the ratio coefficients from level 1 to level m gradually decrease, where m is a natural number greater than or equal to 4. The values ​​of P and m and the value of the ratio coefficient can be selected and adjusted by those skilled in the art according to actual conditions.

[0074] Step S6: Superimpose the multi-level amplitudes of the three original loads on the corresponding load mean values ​​to obtain the multi-level loads, then calculate the number of times each level of load acts based on the load amplitude distribution model, and calculate the probability distribution of each level of load acts based on the number of times each level of load acts, so as to obtain the multi-level load spectrum of the three original loads under the actual working conditions of the main bearing.

[0075] Preferably, the load mean average value is obtained by weighting the load mean and the number of times it acts.

[0076] Furthermore, in step S6, based on the load amplitude distribution model, the number of times the first-level load acts is set to 1, and the number of times the other m-1-level load acts is calculated according to equations 9) and 10).

[0077]

[0078] n j =N j -N j-1 Formula 10),

[0079] In formula 9), N i represents the cumulative number of load actions from level 1 to the i-th level, i is a natural number from 1 to m; in formula 10), n j Indicates the number of times the j-th level load acts, N j It indicates the cumulative number of times the load from level 1 to level j acts, where j is a natural number from 2 to m.

[0080] It can be understood by those skilled in the art that when i and j have the same value, N i and N j Essentially, they represent the same parameter, and two expressions are used here only to distinguish the parameters in equation 9) and equation 10).

[0081] Preferably, in step S6, the probability distribution of load action at each level is calculated according to formula 11),

[0082]

[0083] Among them, P i represents the probability of the i-th level load acting.

[0084] In addition, this embodiment also provides a specific application case of the compilation method:

[0085] In this application case, the telescopic cylinder pressure acquisition frequency is set to 1 time / minute, and the acquisition time is 10699 minutes.

[0086] Among them, the value of P is 10 -6 , m takes the value of 8, that is, 8 levels of amplitude are obtained, and the ratio coefficients of levels 1 to 8 are 1.000, 0.950, 0.850, 0.725, 0.575, 0.425, 0.275, and 0.125 respectively.

[0087] According to the compilation method of this embodiment, the actual working condition load spectrum of the main bearing is obtained, wherein the eight-level load spectrum of axial force, radial force and overturning moment is shown in Tables 1 to 3 below:

[0088] Table 1 Axial force eight-level load spectrum

[0089]

[0090] Table 2 Eight-level radial force load spectrum

[0091]

[0092] Table 3 Overturning moment eight-level load spectrum

[0093]

[0094] The compilation method of this embodiment is based on the axial load-bearing characteristics of the main bearing. By detecting the pressure of the telescopic cylinder, accurate and reliable original load time history of the main bearing axial force and overturning moment can be obtained. Based on the radial load-bearing characteristics of the main bearing, the original load time history of the main bearing radial force is obtained by multiplying the gravity of the structural parts with the engineering coefficient, thereby solving the problem of the difficulty in extracting the three loads of axial force, radial force and overturning moment acting on the main bearing under actual working conditions.

[0095] The load spectrum of the main bearing under actual working conditions is obtained through the processes of rain flow counting method, load distribution model establishment, load classification processing and load action times calculation. The random, disordered and drastic original load time history under actual working conditions is converted into a load spectrum with equivalent effect, thereby providing reliable input conditions for main bearing design verification, theoretical analysis and working condition testing.

[0096] 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 method for compiling a load spectrum of a main bearing of a tunnel boring machine, characterized in that: The following steps are involved: Step S1: measuring the pressure of n telescopic cylinders arranged along the circumferential direction at the rear end of the main bearing, and calculating the original load time history of the axial force and overturning moment exerted on the main bearing; Step S2: Obtain the gravity of the front end structural component of the main bearing, multiply the gravity of the structural component by the engineering coefficient to obtain the radial force original load time history of the main bearing, and ensure that the data volume of the radial force original load time history is the same as the data volume of the axial force and overturning moment original load time history; Step S3: Based on the rain flow counting method, the load amplitude, load mean and the number of times the three original loads act are obtained respectively; Step S4: using a statistical distribution model to fit the acquired load amplitude and its action times, load mean and its action times, respectively, to obtain the load amplitude and load mean distribution models of the three original loads; Step S5: Based on the obtained load amplitude distribution model, a load with an occurrence probability of P is selected on the right side of the distribution model as the amplitude maximum value, and the amplitude maximum value is multiplied by the ratio coefficients of multiple levels to obtain a multi-level amplitude; Step S6: Superimpose the multi-level amplitudes of the three original loads on the corresponding load mean values ​​to obtain the multi-level loads, then calculate the number of times each level of load acts based on the load amplitude distribution model, and calculate the probability distribution of each level of load acts based on the number of times each level of load acts, so as to obtain the multi-level load spectrum of the three original loads under the actual working conditions of the main bearing.

2. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 1, characterized in that: In step S1, the axial force and overturning moment of the main bearing are calculated according to equations 1) to 4): Among them, F a is the axial force on the main bearing, M is the overturning moment on the main bearing, F i is the pressure applied by the i-th telescopic cylinder, n is the number of telescopic cylinders, l ix , l iy are the distances from the i-th telescopic cylinder to the y-axis and x-axis, M x 、M y It is the torque generated by the telescopic cylinder on the main bearing in the x-axis and y-axis directions.

3. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 1, characterized in that: The engineering coefficient is 1+k, where k is a random number between 0 and 1.

4. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 1, characterized in that: In step S3, MATLAB programming is used to process the original load time history of the axial force, radial force and overturning moment, and the load amplitude, load amplitude action times, load mean and load mean action times of the three original loads are obtained respectively.

5. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 1, characterized in that: In step S4, the load amplitude and the number of times the load amplitude acts are fitted using a three-parameter Weibull distribution, and the load mean and the number of times the load mean acts are fitted using a normal distribution.

6. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 5, characterized in that: The three-parameter Weibull distribution model is shown in Equation 5), and the normal distribution model is shown in Equation 6). Among them, f(x a ) is the amplitude x a The probability density function of f(x m ) is the mean x m is the probability density function of , σ is the shape parameter, μ is the location parameter, π is the circumference of a circle, and e is the base of the natural logarithm.

7. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 6, characterized in that: In step S5, the multi-level amplitude is calculated according to equation 7)-equation 8), x ai =K i ·x amax Formula 8), Among them, x amax is the maximum amplitude, x ai is the i-th level amplitude, K i is the ratio coefficient of the i-th level.

8. The method for compiling a main bearing load spectrum of a tunnel boring machine according to claim 7, characterized in that: There are m levels of ratio coefficients, and the ratio coefficients from level 1 to level m gradually decrease.

9. The method for compiling a load spectrum of a main bearing of a tunnel boring machine according to claim 8, characterized in that: In step S6, based on the load amplitude distribution model, the number of times the first-level load acts is set to 1, and the number of times the other m-1-level load acts is calculated according to equations 9) and 10). n j =N j -N j-1 Formula 10), In formula 9), N i represents the cumulative number of load actions from level 1 to the i-th level, i is a natural number from 1 to m; in formula 10), n j Indicates the number of times the j-th level load acts, N j It indicates the cumulative number of times the load from level 1 to level j acts, where j is a natural number from 2 to m.

10. The method for compiling a main bearing load spectrum of a tunnel boring machine according to claim 9, characterized in that: In step S6, the probability distribution of load action at each level is calculated according to formula (11): Among them, P i represents the probability of the i-th level load acting.

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