CN115935721B - Method for simulating impact force of wheel rail at three-dimensional geometric irregularity of steel rail surface - Google Patents
Method for simulating impact force of wheel rail at three-dimensional geometric irregularity of steel rail surface Download PDFInfo
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Abstract
The invention discloses a method for simulating wheel rail impact force at a three-dimensional geometrical irregularity position on a steel rail surface, which comprises the following steps: acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail; establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity; obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method; establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution; and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail. According to the method, the contact point and the geometric gap distribution of the three-dimensional geometric irregularity are obtained through the real geometric profiles of the discrete wheels and the steel rail, the accurate three-dimensional contact model is utilized for solving to obtain the contact mechanical behavior, and then the contact mechanical behavior is brought into the vehicle-rail coupling dynamics to obtain the dynamic wheel-rail force.
Description
Technical Field
The invention relates to the technical field of rail transit, in particular to a method for simulating wheel rail impact force at a three-dimensional geometrical irregularity position of a steel rail surface.
Background
The shortwave geometric irregularity of the surface of the steel rail can excite high wheel rail impact force due to the change of the vertical position of the center of mass of the wheel pair, and is one of the main reasons for influencing the safe running of a train, the riding comfort of passengers and the noise level along the railway. Accurate assessment of wheel rail impact levels is very important to ensure safe, stable, economical operation of railways. In view of the fact that the existing test technology cannot effectively capture the mechanical behavior in the wheel track contact spots, establishing a numerical model is the most effective means for researching the dynamic contact behavior of the wheel track at present.
In the 70 s of the 20 th century, with the vigorous development of the railway transportation industry, the research of wheel-rail dynamic interaction is greatly promoted. Among the representative results are the tests and theoretical studies conducted by the Derby railway technology research center in England on the dynamic effects of the wheel rail at the rail joints. One of the most important findings is to define two types of forces objectively existing during track impact, namely high frequency impact force P1 and medium and low frequency response force P2. Meanwhile, jenkins et al studied the influence of vehicle-rail system parameters on these two types of forces in detail using their numerical models. Subsequently, newton and Clark have improved models of Jenkins to improve computational accuracy, including making Euler Liang Tihuan a Timoshenko beam to account for rail shear strain, supporting a continuous beam to simulate rails with elastic points, accounting for the effects of tie vibration, and the like. In nineties, the Wanming institution in China first treated the two subsystems of the vehicle and the rail as a mutually coupled integral system, and more completely considered the dynamic factors of the components of the vehicle-rail system. The vehicle-track coupling dynamics theory and analysis model proposed thereby has become the basic method for researching railway system dynamics.
In addition to the above-described multi-body dynamics approach, some students began to build three-dimensional wheelset-track rolling contact explicit dynamics models by means of finite element methods, in which the wheeltrack system was simulated using solid elements, and the contact was processed using penalty function or Lawster's method, taking into account the damping of the wheeltrack material. Therefore, the energy dissipation effect caused by the flexible deformation, the instantaneous contact mechanical behavior and the elastoplastic deformation of the wheel track structure can be accurately considered. A wheel set-rail joint transient impact finite element model is established by utilizing ANSYS/LS-DYNA commercial software such as Wen Zefeng, and dynamic contact force in the collision process of wheels and joints is analyzed in an important way; li Zili and Zhao Xin developed this transient finite element model and were successfully applied to the study of rail weld zone Squats damage problems. The Zhao Xin detailed comparison of the differences in short wave geometric irregularity impact problem simulation is specific to the multi-rigid-body dynamics model and the transient finite element model, and the results show that the differences of the prediction results of the multi-rigid-body dynamics model and the transient finite element model are obvious. Although the finite element method is accurate, the calculation process is time-consuming, and the simulation of the rolling distance of 1m usually takes tens of hours, so that the finite element method cannot be widely used for engineering calculation. Therefore, the vehicle-track coupling dynamics method is more adopted in the research of the wheel track impact force simulation at the geometrical irregularity, but the calculation accuracy is required to be improved.
In vehicle-track coupling dynamics, the wheel-track contact model is a hertz nonlinear spring. The method is a simplified method based on the Hertz contact theory, namely 'point contact', the contact rigidity is assumed to be only related to the radius of a contact body, the fluctuation of the contact force of the wheel track is considered through the change of the geometric irregularity on the elastic compression amount, and the change of the shape of the contact spot of the wheel track at the geometric irregularity cannot be considered. Therefore, the Hertz nonlinear spring can only consider two-dimensional geometric irregularity when describing wheel track impact, and cannot consider real contact mechanical behavior at the three-dimensional geometric irregularity, which is one of main factors limiting the calculation accuracy of the wheel track impact force. The wheel track impact force simulation method based on the Hertz nonlinear spring can only consider two-dimensional geometric irregularity, so three disadvantages exist: 1) The change of the elastic compression quantity along with the running distance is assumed to be two-dimensional geometric irregularity along the longitudinal and vertical directions of the steel rail, namely, given two-dimensional geometric irregularity is assumed to participate in the vibration of a wheel rail system, and the vertical displacement change of the center of mass of the wheel set at the position of a real contact point under the three-dimensional geometric irregularity cannot be considered; 2) The contact spots of the wheel rail at the geometric irregularity are assumed to be circular, and the contact rigidity is assumed to be constant, so that the influence of the geometric irregularity on the contact mechanical behavior of the wheel rail (expressed as time-varying contact rigidity) cannot be reflected; 3) The influence of the geometrical irregularity width on the wheel-rail force cannot be considered.
Therefore, there is a need for a method that accounts for variations in wheel-rail contact stiffness at three-dimensional geometric irregularities and is suitable for rapid real-time computation in vehicle-rail coupling dynamics.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a simulation method of wheel-rail impact force at the three-dimensional geometrical irregularity of the surface of a steel rail, and provides a contact geometry solving method which considers the three-dimensional geometrical irregularity of the surface of the steel rail and the motion gesture of a wheel set, wherein the position of a contact point of the wheel rail and the geometrical gap distribution nearby the contact point can be determined so as to reflect the real vertical displacement of the mass center of the wheel set and the width change of the geometrical irregularity; the three-dimensional contact mechanical model for solving any geometric gap distribution is established, the change of the contact stiffness of the wheel track at the three-dimensional geometric irregularity can be considered, and the method is suitable for carrying out rapid real-time calculation in the coupling dynamics of the vehicle and the track, and solves the problems in the prior art.
In order to achieve the above purpose, the present invention provides the following technical solutions: a method for simulating wheel rail impact force at a three-dimensional geometrical irregularity position on the surface of a steel rail comprises the following steps:
s1, acquiring three-dimensional geometric irregularity distribution data of a steel rail surface;
s2, establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
s3, obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method;
s4, establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution;
s5, establishing a vehicle-track coupling dynamics model, and solving the impact force of the wheel track at the geometrical irregularity of the three-dimensional surface of the steel rail.
Preferably, in step S1, the obtaining the three-dimensional geometrical irregularity distribution data of the surface of the steel rail specifically includes: and scanning the surface of the steel rail by adopting a compound three-dimensional scanner to obtain three-dimensional geometrical irregularity distribution data of the steel rail.
Preferably, the step S2 specifically includes:
s21, positioning the coordinate system of the steel railOxyzConversion into a tangential plane coordinate system in which a three-dimensional geometric irregularity of a surface is locatedOx’y’z’The conversion formula is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,αandβrepresenting the contact angle at the contact point and the rail base slope, respectively;
s22, atOx’y’z’Applying measured or ideal rail surface three-dimensional geometric irregularities in a coordinate systemOx’y’ z’Geometrical transformation of newly acquired profile in system back to original coordinate systemOxyzThe geometric profile of the three-dimensional steel rail containing any three-dimensional geometric irregularity is obtained, and the conversion formula is as follows:
preferably, the step S3 specifically includes:
s31, setting a constant section which is smooth along the longitudinal direction and comprises a steel rail with three-dimensional geometrical irregularity, and obtaining potential wheel rail contact points under any attitude of the wheel set by using a trace method;
s32, dispersing real three-dimensional geometric profiles of wheels and steel rails at potential wheel-rail contact points, and obtaining final wheel-rail contact points by using a space vector method;
s33, calculating three-dimensional contact geometric gap distribution near the contact point of the wheel trackh(x,y) The calculation expression is as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,
and->
Three-dimensional space coordinates of the geometric profiles of the wheels and the steel rails are respectively obtained.
Preferably, the step S4 specifically includes:
s41, taking the three-dimensional contact geometric gap distribution in the step S3 as an input parameter, inputting the input parameter into INFCON and TRIAL model algorithms, and obtaining an approximate solution of a wheel-rail contact result;
s42, establishing residual energy expression of the three-dimensional wheel-rail contact problem, taking the result obtained in the step S41 as an initial solution, and obtaining an accurate wheel-rail contact solution by using an Extended CG model algorithm, wherein the residual energy expression comprises the following steps of:
wherein Pn is a compressive stress matrix; h is a contact geometry gap matrix; a is an influence factor matrix;
as the compressive stress of an arbitrary unit,Ttranspose of matrix, +.>
For the expression of the complementary energy of Pn,subthe condition that the complementary energy expression is established.
Preferably, the step S5 specifically includes:
s51, establishing a vehicle-track coupling dynamics model, wherein the vehicle model comprises a vehicle body, a framework, wheel pairs and a suspension device, and the track model comprises steel rails, a fastener system and a track bed; the vehicle body and the framework are rigid bodies, and the suspension device and the fastener system are simulated by adopting spring-damping units;
s52, bringing the wheel-rail contact solution obtained in the step S4 into a vehicle-rail coupling dynamics model, and solving the accurate wheel-rail impact force at the three-dimensional geometrical irregularity of the surface of the steel rail at the running time of each vehicle.
In addition, in order to achieve the above purpose, the present invention further provides the following technical solutions: a device for simulating wheel rail impact force at a three-dimensional geometric irregularity of a rail surface, the device comprising:
and a data acquisition module: acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail;
the three-dimensional steel rail geometric profile building module comprises: establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
the three-dimensional contact geometric gap distribution calculation module comprises: obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method;
wheel-rail contact solution calculation module: establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution;
wheel rail impact solving module: and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail.
In addition, in order to achieve the above purpose, the present invention further provides the following technical solutions: an apparatus, the apparatus comprising: a processor; and a memory for storing one or more programs;
the one or more programs, when executed by the processor, cause the processor to perform the simulation method.
In addition, in order to achieve the above purpose, the present invention further provides the following technical solutions: a computer readable storage medium having stored thereon a computer program which when executed by a processor implements the simulation method.
The beneficial effects of the invention are as follows:
1) The invention provides a method for simulating wheel-rail impact force at a three-dimensional geometrical irregularity on a steel rail surface, which is characterized in that contact points and geometrical gap distribution at the three-dimensional geometrical irregularity are obtained through the real geometrical profiles of discrete wheels and the steel rail, an accurate three-dimensional contact model is utilized for solving to obtain contact mechanical behaviors, and then the contact mechanical behaviors are brought into vehicle-rail coupling dynamics to obtain dynamic wheel-rail force. The numerical calculation example shows that the method can consider three-dimensional geometric irregularity and obtain more accurate calculation results.
2) The invention can efficiently solve the wheel-rail contact mechanical behavior of the three-dimensional geometric irregularity, so that the vehicle-rail coupling dynamics can consider the refined wheel-rail contact in real time. On the one hand, when the contact points and the geometric gaps are distributed, the trace method and the space vector method are combined, and the geometric characteristics of the concerned region can be obtained by using a small number of grids; on the other hand, the invention establishes the three-dimensional asymmetric wheel-rail contact model, which is formed by combining the simplified infcon+three algorithm model and the accurate Extended CG algorithm contact model, and can obtain accurate contact mechanical behavior with less iteration times, thereby having high operation efficiency.
Drawings
FIG. 1 is a schematic diagram of a wheel-rail impact force simulation and a contact patch based on a Hertz nonlinear spring in the prior art, (a) is a schematic diagram of the wheel-rail impact force simulation, and (b) is a schematic diagram of the shape of the contact patch;
FIG. 2 is a flow chart of the steps of the method of the present invention;
FIG. 3 is a schematic diagram of a vehicle-rail coupling dynamics model in example 1;
FIG. 4 is a schematic view showing the three-dimensional geometrical irregularity distribution of the rail surface in example 2;
FIG. 5 is a schematic view of the three-dimensional wheel-rail contact and the contact point positions of the wheel-rail at different running distances in example 2, (a) the three-dimensional wheel-rail contact, and (b) the contact point positions of the wheel-rail at different running distances;
FIG. 6 is a schematic diagram showing the evolution of the geometrical gap distribution of the contact points of the three-dimensional wheel rail in example 2, (a) at 1/4 wavelength; (b) at a wavelength of 1/2; (c) at a wavelength of 5/8;
FIG. 7 is a graph of variation in impact force of a wheel track with geometric irregularities in example 2;
FIG. 8 is a graph showing the comparison of the geometric irregularity along the longitudinal vertical direction and the wheel set center of mass vertical displacement and the impact force on the wheel rail, (a) showing the distribution of the geometric irregularity along the longitudinal vertical direction of the wheel set center of mass vertical displacement and the input, and (b) showing the impact force on the corresponding wheel rail;
FIG. 9 is a graph showing the comparison of the calculated variation of the contact stiffness along the geometrical irregularity and the influence of the calculated variation of the contact stiffness along the geometrical irregularity on the wheel track impact force according to the present invention and the prior art, (a) a graph showing the comparison of the calculated variation of the contact stiffness along the geometrical irregularity according to the present invention and the prior art, and (b) a graph showing the influence of the corresponding wheel track impact force;
FIG. 10 is a schematic illustration of the effect of geometric irregularity on wheel track impact;
FIG. 11 is a schematic diagram of a module assembly of an exemplary simulation apparatus according to the present invention;
FIG. 12 is a schematic diagram of a device structure according to an embodiment of the present invention;
in the figure, 110-a data acquisition module; 120-a three-dimensional steel rail geometric profile building module; 130-a three-dimensional contact geometry gap distribution calculation module; 140-a wheel-rail contact solution calculation module; 150-a wheel track impact solving module; 210-a processor; 220-memory.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the research of coupling dynamics of vehicles and rails, a Hertz nonlinear spring is generally adopted to simulate wheel-rail contact, and as shown in fig. 1, the wheel-rail contact force isF n By contact stiffness in (1)C H And an elastic compression amount
The calculation is performed such that,
when the shape of the contact patch is assumed to be circular, as shown in formula (2), the contact stiffnessC H From modulus of elasticityEPoisson's ratiovAnd wheelRadius of radiusRIt is decided that the method comprises the steps of,
the impact of geometric irregularities on the impact force of the wheel tracks is reflected by changing the amount of elastic compression between the wheel tracks,
in the method, in the process of the invention,x w andx r vertical vibration displacement of the wheels and the steel rail respectively;z(x) Is a two-dimensional geometric irregularity which varies vertically along the rail.
The wheel-rail impact force simulation method based on the Hertz nonlinear spring can only consider two-dimensional geometric irregularity and cannot consider real contact mechanical behavior of the three-dimensional geometric irregularity, so the inventor provides a wheel-rail impact force simulation method of the three-dimensional geometric irregularity of the surface of the steel rail aiming at the problems, and aims to solve the problems in the prior art.
Example 1
The embodiment provides a technical scheme: a method for simulating wheel rail impact force at a three-dimensional geometrical irregularity of a steel rail surface is shown in fig. 2, and comprises the following steps:
s1, acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail.
In the specific implementation process, two methods are available for acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail.
1) The method adopts a compound three-dimensional scanner (such as a HandySCAN 3D) to scan the surface of the steel rail to obtain three-dimensional geometrical irregularity distribution data, and comprises the following working steps: (1) two groups of cameras on the instrument can respectively obtain laser projected onto the surface of the steel rail, and linear three-dimensional information of the steel rail projected by the laser line is obtained through calculation; (2) the instrument determines the space position of the scanner according to the visual mark points fixed on the surface of the steel rail; (3) the scanner is controlled to continuously move and acquire three-dimensional information of the position where the laser passes, so that continuous three-dimensional data are formed.
2) The method for generating the three-dimensional geometrical irregularity distribution data of the steel rail surface through the theoretical formula comprises the following steps:
(1) the geometrical irregularity distribution of the rail along the train running direction is regarded as a cosine function as shown in formula (4).
Wherein, the liquid crystal display device comprises a liquid crystal display device,l c andd c is the irregularity wavelength and wave depth;x 0 a starting position for applying irregularities;xis the position of the irregularity along the train running direction.
(2) On the basis of the formula (1), the geometric variation of the surface irregularity of the steel rail in the transverse direction is defined as a parabola, as shown in the formula (5).
Wherein, the liquid crystal display device comprises a liquid crystal display device,
is the irregularity wave width; />
Is the vertical coordinate in the lateral direction of the irregularity.
S2, establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity.
1) Coordinate system of steel railOxyzConversion into a tangential plane coordinate System where the surface three-dimensional geometric irregularity is located by the method of (6)Ox’y’z’，
Wherein, the liquid crystal display device comprises a liquid crystal display device,αandβrepresenting the contact angle at the contact point and the rail base slope, respectively.
2) At the position ofOx’y’z’Applying measured or ideal rail surface three-dimensional geometric irregularities in a coordinate systemWill then be atOx’ y’z’The newly acquired profile geometry in the system is converted back to the original coordinate system using (7)OxyzObtaining the geometric profile of the three-dimensional steel rail containing any three-dimensional geometric irregularity,
s3, obtaining the contact point of the wheel track and the three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method.
1) Firstly, assuming that a steel rail containing three-dimensional geometric irregularity is a smooth constant section along the longitudinal direction, and obtaining potential wheel rail contact points under the condition of any attitude (head shaking angle and sideslip amount) of the wheel set by using a trace method.
2) And then dispersing the real three-dimensional geometrical profiles of the wheels and the steel rails at the potential wheel-rail contact points, and obtaining the final wheel-rail contact points by using a space vector method.
3) Finally, calculating the three-dimensional contact geometric gap distribution near the contact point of the wheel track by adopting the method (8)h(x,y)。
Wherein, the liquid crystal display device comprises a liquid crystal display device,
and->
Three-dimensional space coordinates of the geometric profiles of the wheels and the steel rails are respectively obtained.
And S4, establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution.
1) Taking the three-dimensional contact geometric gap distribution in the step S3 as an input parameter, inputting the input parameter into INFCON and TRIAL model algorithms, and obtaining an approximate solution of a wheel-rail contact result;
2) And (3) establishing residual energy expression of the three-dimensional wheel-rail contact problem, wherein the residual energy expression is shown in a formula (9), taking the result obtained in the step (S41) as an initial solution, and obtaining an accurate wheel-rail contact solution comprising a spot shape, a compressive stress distribution and a total vertical force by using an Extended CG model algorithm proposed by Polonsky-Keer.
Wherein Pn is a compressive stress matrix; h is a contact geometry gap matrix; a is an influence factor matrix;
as the compressive stress of an arbitrary unit,Ttranspose of matrix, +.>
For the expression of the complementary energy of Pn,subthe condition that the complementary energy expression is established.
The high-efficiency calculation of the method is embodied in that the iteration times of the Extended CG algorithm can be greatly reduced by the initial solution.
S5, establishing a vehicle-track coupling dynamics model, and solving the impact force of the wheel track at the geometrical irregularity of the three-dimensional surface of the steel rail.
1) Establishing a vehicle-track coupling dynamics model, wherein the vehicle model comprises a vehicle body, a framework, wheel pairs and a suspension device, and the track model comprises steel rails, a fastener system and a track bed; the vehicle body and the framework are rigid bodies, and the suspension device and the fastener system are simulated by adopting spring-damping units; a schematic diagram of the model is shown in fig. 3.
2) And (3) bringing the wheel-rail contact solution obtained in the step (S4) into a vehicle-rail coupling dynamics model, and solving the accurate wheel-rail impact force at the three-dimensional geometrical irregularity of the surface of the steel rail at the running moment of each vehicle.
Example 2
The description of the method of the invention is given by taking the ideal three-dimensional geometrical irregularity of the rail surface as an example. Typical dimensions of three-dimensional geometric irregularities, among others: the wavelength, depth and width were 40mm, 0.2mm and 40mm, respectively.
Step1: the spatial distribution of the three-dimensional geometrical irregularity is obtained by using the formulas (4) and (5).
Step2: the geometric irregularities were applied to the rail surface as described in section 4.2, step2, and the results are shown in fig. 4.
Step3: the method described in step3 of section 4.2 is used to determine the track contact point position, as shown in fig. 5 (a), and the track contact point positions at different travel distances are schematically shown in fig. 5 (b). Further, the three-dimensional contact geometry gap distribution in the vicinity of the wheel-rail contact point was obtained by using equation (8), and the result is shown in fig. 6. Wherein, fig. 6 (a), 6 (b) and 6 (c) respectively show the gap distribution evolution at 1/4 wavelength, 1/2 wavelength and 5/8 wavelength, and the graph can find that the contact geometric gap has obvious difference at different positions after considering the three-dimensional geometric irregularity of the surface of the steel rail.
Step4& Step5: and (3) obtaining a wheel-rail contact solution by using the method in the step (4), and substituting the wheel-rail contact solution into a vehicle-rail coupling dynamics model to obtain the change of the impact force of the wheel rail along with the running distance of the wheel set, as shown in fig. 7.
The method of the present invention compares the three aspects of vertical displacement variation from the wheel pair centroid, contact stiffness and geometric irregularity width with conventional methods, as shown in fig. 8, 9 and 10.
Fig. 8 (a) compares the vertical displacement of the wheel set centroid along the travel distance with the vertical distribution of input geometric irregularities. A large difference can be found between the two because there is a longitudinal offset of the contact point from the center of the wheel set. Since the result is to perform the vibration reference by changing the elastic compression amount between the wheel tracks, the impact force of the wheel tracks is liable to be changed, and as shown in fig. 8 (b), the necessity of determining the vertical displacement of the center of mass of the wheel pair by solving the actual contact point position can be seen.
As can be seen from a comparison of the geometrical irregularity changes in the contact stiffness calculated in fig. 9 (a), the contact stiffness increases as the contact point of the wheel track approaches the trough according to the method of the present invention, i.e. the contact stiffness is not constant under three-dimensional geometrical irregularity, because the shape of the contact spot changes significantly. In contrast, the calculated contact stiffness of the hertz nonlinear spring remains constant. Fig. 9 (b) shows the wheel-rail impact calculated for the inventive method compared to the hertz nonlinear spring, and it can be found that the wheel-rail impact is smaller for the inventive method compared to the result of the hertz nonlinear spring, because the contact stiffness starts to decay at the maximum wheel-rail impact.
Fig. 10 shows the effect of geometric irregularity width on wheel-rail impact, and it can be seen that the wheel-rail impact increases with increasing width, because geometric irregularity width changes the wheel-set centroid vertical displacement variation and contact stiffness variation, which cannot be simulated by the hertz-based nonlinear spring method, and therefore it is necessary for the method of the present invention to consider true three-dimensional geometric irregularities.
Further, based on the same inventive concept as the above method embodiment, the present application further provides a device for simulating an impact force of a wheel track at a three-dimensional geometrical irregularity of a surface of a steel rail, as shown in fig. 11, where the device may implement the functions provided by the above method embodiment, and the device includes:
the data acquisition module 110: acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail;
three-dimensional rail geometry profile creation module 120: establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
the three-dimensional contact geometry gap distribution calculation module 130: obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method;
wheel-rail contact solution calculation module 140: establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution;
wheel rail impact solution module 150: and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail.
Further, based on the same inventive concept as the above method embodiment, the present application further provides an apparatus, which may implement the functions provided by the above method embodiment, as shown in fig. 12, where the apparatus includes: a processor 210; and a memory 220 for storing one or more programs;
the one or more programs, when executed by the processor 210, cause the processor to perform the simulation method.
The simulation method comprises the following steps:
acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail;
establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method;
establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution;
and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail.
Further, based on the same inventive concept as the above-described method embodiments, the present application also provides a computer-readable storage medium having stored thereon a computer program that, when executed by the processor 210, implements the simulation method.
The simulation method comprises the following steps:
acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail;
establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
obtaining wheel-rail contact points and three-dimensional asymmetric contact geometric gap distribution by using a space geometric solving method;
establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution;
and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail.
The invention can efficiently solve the wheel-rail contact mechanical behavior of the three-dimensional geometric irregularity, so that the vehicle-rail coupling dynamics can consider the refined wheel-rail contact in real time. On the one hand, when the contact points and the geometric gaps are distributed, the trace method and the space vector method are combined, and the geometric characteristics of the concerned region can be obtained by using a small number of grids; on the other hand, the invention establishes the three-dimensional asymmetric wheel-rail contact model, which is formed by combining the simplified infcon+three algorithm model and the accurate Extended CG algorithm contact model, and can obtain accurate contact mechanical behavior with less iteration times, thereby having high operation efficiency.
Although the present invention has been described with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements and changes may be made without departing from the spirit and principles of the present invention.
Claims (7)
1. A method for simulating wheel rail impact force at a three-dimensional geometrical irregularity position on the surface of a steel rail is characterized by comprising the following steps:
s1, acquiring three-dimensional geometric irregularity distribution data of a steel rail surface;
s2, establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
s3, obtaining the geometrical gap distribution of the wheel-rail contact point and the three-dimensional asymmetric contact by using a space geometrical solving method, wherein the method comprises the following specific steps of:
s31, setting a constant section which is smooth along the longitudinal direction and comprises a steel rail with three-dimensional geometrical irregularity, and obtaining potential wheel rail contact points under any attitude of the wheel set by using a trace method;
s32, dispersing real three-dimensional geometric profiles of wheels and steel rails at potential wheel-rail contact points, and obtaining final wheel-rail contact points by using a space vector method;
s33, calculating three-dimensional contact geometric gap distribution h (x, y) near a wheel track contact point, wherein the calculation expression is as follows:
h(x，y)＝z w (x，y)-z r (x，y)，
wherein z is w (x, y) and z r (x, y) are three-dimensional space coordinates of the geometric profiles of the wheels and the rails respectively;
s4, establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution, wherein the method specifically comprises the following steps of:
s41, taking the three-dimensional contact geometric gap distribution in the step S3 as an input parameter, inputting the input parameter into INFCON and TRIAL model algorithms, and obtaining an approximate solution of a wheel-rail contact result;
s42, establishing residual energy expression of the three-dimensional wheel-rail contact problem, taking the result obtained in the step S41 as an initial solution, and obtaining an accurate wheel-rail contact solution by using an Extended CG model algorithm, wherein the residual energy expression comprises the following steps of:
wherein Pn is a compressive stress matrix; h is a contact geometry gap matrix; a is an influence factor matrix; p is p I The compressive stress of any unit is represented by T, which is the transposition of a matrix, phi is the complementary energy expression of Pn, and sub is the condition that the complementary energy expression is established;
s5, establishing a vehicle-track coupling dynamics model, and solving the impact force of the wheel track at the geometrical irregularity of the three-dimensional surface of the steel rail.
2. The method for simulating wheel rail impact force at three-dimensional geometrical irregularities of a steel rail surface according to claim 1, wherein the method comprises the steps of: in step S1, the obtaining the three-dimensional geometrical irregularity distribution data of the steel rail surface specifically includes: and scanning the surface of the steel rail by adopting a compound three-dimensional scanner to obtain three-dimensional geometrical irregularity distribution data of the steel rail.
3. The method for simulating wheel rail impact force at three-dimensional geometrical irregularities of a steel rail surface according to claim 1, wherein the method comprises the steps of: the step S2 specifically includes:
s21, converting a coordinate system Oxyz of a steel rail into a tangential plane coordinate system Ox ' y ' z ' of a surface three-dimensional geometrical irregularity, wherein the conversion formula is as follows:
wherein α and β represent the contact angle at the contact point and the rail base slope, respectively;
s22, applying actual measurement or ideal three-dimensional geometric irregularity of the surface of the steel rail in the Ox 'y' z 'coordinate system, and converting the newly acquired profile geometry in the Ox' y 'z' system back to the original coordinate system Oxyz to obtain the three-dimensional geometric profile of the steel rail containing any three-dimensional geometric irregularity, wherein the conversion formula is as follows:
4. the method for simulating wheel rail impact force at three-dimensional geometrical irregularities of a steel rail surface according to claim 1, wherein the method comprises the steps of: the step S5 specifically includes:
s51, establishing a vehicle-track coupling dynamics model, wherein the vehicle model comprises a vehicle body, a framework, wheel pairs and a suspension device, and the track model comprises steel rails, a fastener system and a track bed; the vehicle body and the framework are rigid bodies, and the suspension device and the fastener system are simulated by adopting spring-damping units;
s52, bringing the wheel-rail contact solution obtained in the step S4 into a vehicle-rail coupling dynamics model, and solving the accurate wheel-rail impact force at the three-dimensional geometrical irregularity of the surface of the steel rail at the running time of each vehicle.
5. A simulator for wheel rail impact force at a three-dimensional geometrical irregularity position on a steel rail surface is characterized in that: the device comprises:
data acquisition module (110): acquiring three-dimensional geometric irregularity distribution data of the surface of the steel rail;
three-dimensional rail geometry profile creation module (120): establishing a three-dimensional steel rail geometric profile containing any three-dimensional geometric irregularity;
a three-dimensional contact geometry gap distribution calculation module (130): the method for obtaining the geometrical gap distribution of the wheel-rail contact point and the three-dimensional asymmetric contact by using a space geometrical solving method comprises the following specific steps:
providing a constant section which comprises a steel rail with three-dimensional geometrical irregularity and is smooth along the longitudinal direction, and obtaining potential wheel rail contact points under any attitude of the wheel set by utilizing a trace method;
the actual three-dimensional geometrical profiles of the discrete wheels and the steel rail at the potential wheel-rail contact points are obtained by using a space vector method;
the three-dimensional contact geometry gap distribution h (x, y) near the wheel-rail contact point is calculated as follows:
h(x,y)＝z w (x,y)-z r (x,y)，
wherein z is w (x, y) and z r (x, y) are three-dimensional space coordinates of the geometric profiles of the wheels and the rails respectively;
wheel-rail contact solution calculation module (140): the method comprises the specific steps of establishing a three-dimensional asymmetric wheel-rail contact model and calculating a wheel-rail contact solution, wherein the specific steps comprise the following steps:
taking the three-dimensional contact geometric gap distribution as an input parameter, inputting the input parameter into INFCON and TRIAL model algorithms, and obtaining an approximate solution of a wheel-rail contact result;
establishing residual energy expression of the three-dimensional wheel-rail contact problem, taking the obtained approximate solution as an initial solution, and obtaining an accurate wheel-rail contact solution by using an Extended CG model algorithm, wherein the residual energy expression comprises the following steps:
wherein Pn is a compressive stress matrix; h is a contact geometry gap matrix; a is an influence factor matrix; p is p I The compressive stress of any unit is represented by T, which is the transposition of a matrix, phi is the complementary energy expression of Pn, and sub is the condition that the complementary energy expression is established;
wheel track impact force solving module (150): and (3) establishing a vehicle-track coupling dynamics model, and solving the wheel-track impact force at the geometrical irregularity of the three-dimensional surface of the steel rail.
6. An electronic device, characterized in that: the electronic device includes: a processor (210); and a memory (220) for storing one or more programs;
the one or more programs, when executed by a processor (210), cause the processor to perform the simulation method of any of claims 1-4.
7. A computer-readable storage medium, characterized by: on which a computer program is stored which, when being executed by a processor (210), implements the simulation method according to any of claims 1-4.
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