A general algorithm for calculating equivalent single wheel load of mobile machinery in port pavement structures

Abstract

The present invention discloses a general algorithm for the equivalent single-wheel load of mobile machinery in a port pavement structure. By combining theoretical analysis with numerical solution, corresponding single-wheel load algorithms are designed for multiple types of operating machinery. The present invention can solve the problem of being difficult to calculate the equivalent single-wheel load of new port mobile operating machinery according to current standards in the design of port pavement structures, thus paving the way for the design of pavement structures under the action of special dock machinery.

Description

Technical Field

[0001] The present invention relates to the field of port analysis, and more specifically, to a general algorithm for equivalent single-wheel load of mobile machinery in a port pavement structure. Background Art

[0002] In the process of designing the road yard pavement of the port project, it is necessary to consider the equivalent single-wheel load (i.e. equivalent single-wheel load) generated by various mobile operating machinery on the pavement structure. When calculating the bending and tensile stress at the bottom of the rigid and semi-rigid base layer, the equivalent single-wheel load of the customized mobile machinery is calculated by the side wheel influence coefficient. However, the current industry standard "Design and Construction Specifications for Port Road Yard Pavement" provides fewer types of commonly used mobile port operating machinery and only provides the treatment principles for some mobile machinery (Standard Appendix A.0.2.1 and A.0.2.3): Equivalent single-wheel load of the bending and tensile stress at the bottom of the cement concrete surface layer, forklifts, reach loaders, cranes, gantry cranes with 8 wheels on one side, special container trailers, and domestic flatbed trucks can only count the load of one axle; straddle carriers and gantry cranes with 2 to 4 wheels on one side can count the load of one side wheel.

[0003] With the continuous development of large-scale ships and automated terminals, various new types of port mobile operating machinery have emerged on the market. The wheel load layout of these new operating machinery is difficult to classify into the above types, which brings new difficulties and challenges to the design of related port pavement structures. Therefore, it is necessary to develop a new general algorithm for the equivalent single wheel load of mobile machinery in the port pavement structure. Summary of the invention

[0004] The invention overcomes the defects of the prior art and proposes a general algorithm for equivalent single-wheel load of mobile machinery in a port pavement structure.

[0005] The first aspect of the present invention provides a general algorithm for equivalent single wheel load of mobile machinery in a port pavement structure, which specifically includes theoretical analysis, numerical solution, and algorithm design process, specifically:

[0006] The theoretical analysis is specifically as follows:

[0007] Through theoretical analysis, the main wheel load is simplified to the normal concentrated force on the boundary of a semi-infinite space body. , obtain the stress distribution formula of the main wheel in the cylindrical coordinate system, and obtain the radial stress generated by the main wheel at point Q at a certain depth z below the horizontal plane ;

[0008] Set the wheel load of the first side wheel at a certain distance from the main wheel, calculate the stress distribution formula of the first side wheel in the cylindrical coordinate system, and obtain the radial stress generated by the first side wheel at point z ;

[0009] Set the wheel loads of the second side wheels at different positions and calculate the stress distribution formula of the second side wheels in the cylindrical coordinate system;

[0010] The numerical solution is specifically:

[0011] The stress states of the main wheel, the first side wheel and the second side wheel in the cylindrical coordinate system are converted into stress states in the Cartesian coordinate system through the direction matrix and superimposed to obtain the final stress state distribution;

[0012] Solve the characteristic equation of the horizontal stress state matrix after superposition, and obtain the direction of the principal stress, the corresponding characteristic root, that is, the value of the principal stress ;

[0013] By principal stress value and( ) is used to calculate the incremental ratio of the horizontal tensile stress at point Q of the second side wheelset and take it as the contribution of the bending tensile stress at the bottom of the second side wheelset. If it is a positive value, it indicates that the tensile stress increases, and if it is a negative value, it indicates that the tensile stress decreases;

[0014] Through the above analysis process, within a certain range from the main wheel, when the second side wheel is in the same direction as the line connecting the main wheel and the first side wheel, the bending tensile stress at the bottom of the layer will increase, and when the directions are inconsistent, the bending tensile stress at the bottom of the layer will be reduced. Based on the safety point of view, the effect of the second side wheel can be ignored at this time;

[0015] Based on the above theoretical analysis and numerical solution, the side wheel influence coefficient of mobile machinery with any layout is determined;

[0016] The algorithm design process is specifically as follows:

[0017] After the above theoretical analysis and numerical solution, the algorithm for determining the equivalent single wheel load of mobile working machinery of any layout is based on the following steps:

[0018] S1. Select the main wheel and main wheel load ;

[0019] S2, select the first side wheel , load , determine the first side wheel and the main wheel Direction of the connection , calculate the first side wheel influence coefficient , calculate the side wheel load generated by the first side wheel , superimposed on the main wheel load ;

[0020] S3, traverse other side wheels , calculate the other side wheels and the main wheel Direction of the connection ;

[0021] S4. When the direction or When Side wheel influence coefficient ,when Calculate the side wheel loads generated by the side wheels when ,

[0022] And superimposed on the main wheel load ;when When or and When the directions are inconsistent, ignore the side wheels impact.

[0023] S5, accumulate and obtain the first side wheel Time main wheel Equivalent single wheel load ;

[0024] S6, repeat steps S2 to S5 to obtain the first side wheels are ~ Equivalent load at ~ ;

[0025] S7, take ~ The maximum value of Equivalent single wheel load.

[0026] The present invention can solve the problem of difficulty in calculating the equivalent single wheel load of new port mobile operating machinery according to current standards in the design of port pavement structures, paving the way for the design of pavement structures under the action of special terminal machinery.

[0027] Through perfect theoretical analysis and numerical calculation, the present invention proposes a calculation method with clear meaning, wide application range, and easy implementation through programming, thus clearing the technical obstacles for the compilation of calculation software for port engineering pavement structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flowchart showing a general algorithm for equivalent single wheel load of mobile machinery in a port pavement structure of the present invention is shown;

[0029] Figure 2 A schematic diagram showing the normal concentrated force of the present invention acting on the boundary of a semi-infinite space body;

[0030] Figure 3 The schematic diagram of the stress state in a semi-infinite space under the action of multiple concentrated loads of the present invention is shown;

[0031] Figure 4 It shows the distribution diagram of the principal stress increment ratio generated by the second side wheel of the present invention;

[0032] Figure 5 A schematic diagram of selecting a main wheel is shown;

[0033] Figure 6 It shows a schematic diagram of selecting the first side wheel of the present invention;

[0034] Figure 7 It shows a schematic diagram of traversing other side wheels of the present invention;

[0035] Figure 8 A schematic diagram of calculating the equivalent load by traversing other wheels (such as W3-1) as the first side wheels is shown. DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0038] Figure 1 A flowchart showing a general algorithm for equivalent single wheel load of mobile machinery in a port pavement structure of the present invention is shown;

[0039] like Figure 1 As shown, the first aspect of the present invention provides a general algorithm for equivalent single wheel load of mobile machinery in a port pavement structure, comprising:

[0040] Theoretical analysis:

[0041] According to the design principles of pavement structures, for rigid and semi-rigid pavement structures, when the horizontal bending and tensile stress generated by the bottom layer of the pavement structure under the action of vertical load exceeds the allowable bending and tensile stress of the pavement material, the pavement structure will crack and fail.

[0042] Referring to the treatment method of similar specifications, the wheel load is simplified to the normal concentrated force on the boundary of the semi-infinite space body. According to the classical elastic mechanics model (see Appendix Figure 2 As shown in the figure, the stress generated by the space body at the point Q at a depth Z from the ground and a horizontal projection distance from the action point O can be expressed in cylindrical coordinates:

[0043] ,

[0044] ,

[0045] ,

[0046] ,

[0047] According to the above formula, the load Fixed depth at distance action point On the plane (the bottom layer of the pavement structure), point Q ( ) produces the maximum horizontal tensile stress , and this point is in a uniform tension state; the stress component on the bottom layer of the pavement structure is approximately Inversely proportional to, where For the force The radial stress generated at point Q; For the force Normal stress generated at point Q; For the force The vertical stress generated at point Q; For the force The spatial distance between the point of action O and point Q; is the Poisson's ratio of the soil; For the force Radial and normal shear stresses generated at point Q.

[0048] like Figure 2 , Figure 2 A schematic diagram showing the normal concentrated force of the present invention acting on the boundary of a semi-infinite space body;

[0049] As attached Figure 3 As shown, Figure 3 The schematic diagram of the stress state in a semi-infinite space under the action of multiple concentrated loads of the present invention is shown;

[0050] When the second concentrated load F is at a distance O from the point of action When the horizontal tensile stress is generated at point Q , its direction is from point P to point Q, The tensile stress and The tensile stress generated by the superposition of the two can be directly added, so the load The tensile stress increment coefficient generated at point Q is equal to and The ratio of is the side wheel influence coefficient.

[0051] When connected with OP The third concentrated load of the angle When acting on the ground, the tensile stress generated Direction and Cannot be directly superimposed, in this case, a direction matrix is ​​required The stress state in the cylindrical coordinate system is and Transformed into the stress matrix in Cartesian coordinate system and , the conversion formula is as follows:

[0052] ,

[0053] ,

[0054] ,

[0055] Arrange the above formula to get the conversion formula:

[0056] ,

[0057] in, , , For the force The stresses in the x, y, and z directions generated in the Cartesian coordinate system at point Q; , For the force The shear stress in the xy direction generated in the Cartesian coordinate system at point Q; , For the force The shear stress in the xz direction generated in the Cartesian coordinate system at point Q; , For the force The shear stress in the yz direction generated in the Cartesian coordinate system at point Q; is the angle between the Cartesian coordinate system of point Q and the cylindrical coordinate system;

[0058] Then superimpose the stress matrices of the two loads to obtain the horizontal stress state of the elastic body. By solving the characteristic equation of this horizontal stress state matrix, the direction of the principal stress can be obtained, and its characteristic root is the value of the principal stress. Define the second side wheel The incremental proportion of the resulting "principal stresses" is:

[0059] ,

[0060] In the formula, For load , , The magnitude of the principal stress generated after superposition is For load , The principal stress generated is For load The principal stress generated.

[0061] It should be noted that there is a certain direction difference between the stress component generated by the second side wheel and the stress component generated by the first side wheel, so the total stress after superposition does not always increase.

[0062] Numerical solution process:

[0063] Since the above theoretical solution is too complicated, the second side wheel influence coefficient can be obtained by numerical solution using a computer. Assume that the typical calculation example is as follows:

[0064] The Poisson's ratio of the foundation soil is μ=0, and the equivalent thickness of the surface layer is z=1m. Main wheel load , located at (0m, 0m) coordinates; the first side wheel , located at (-0.6m, 0m); the second side wheel , move arbitrarily within the plane, and solve according to the above formula The ratio of principal stress increments generated at different positions distribution.

[0065] By the attached Figure 4 It can be seen that when the second side wheel When the angle with the first side wheel direction is 180° and 0°, The value of is positive, that is, the principal stress is increasing, and the second side wheel When the direction of the first side wheel is ±90°, when its y coordinate exceeds ±0.6m, , but reduces the horizontal tensile stress at point Q; while the second side wheel When the distance from the main wheel is farther, The above analysis shows that under the combined action of multiple wheel loads, the horizontal tensile stress generated on the bottom of the pavement layer is generated by only considering the proximity coefficient generated by the nearest wheel and its coaxial wheel, and ignoring the proximity coefficients of wheels in other directions. This is a relatively conservative approach.

[0066] Figure 4 It shows the distribution diagram of the principal stress increment ratio generated by the second side wheel of the present invention;

[0067] Detailed explanation of algorithm design:

[0068] As attached Figure 5 Taking the mobile machinery with arbitrary layout as shown in the figure as an example, the equivalent single-wheel load of the main wheel W1-2 that produces bending and tensile stress at the bottom of the rigid and semi-rigid pavement structure layer is calculated.

[0069] S1. Select W1-2 as the main wheel, and its load is the main wheel load , the remaining wheels are used as side wheels. Figure 5 A schematic diagram of selecting a main wheel is shown;

[0070] S2, such as Figure 6 As shown, W2-1 is selected as the first side wheel, and the connection direction between the main wheel W1-2 and the first side wheel W2-1 is determined. , calculate the side wheel influence coefficient of wheel W2-1 , calculate the side wheel load generated , superimposed on the main wheel load ; Figure 6 It shows a schematic diagram of selecting the first side wheel of the present invention;

[0071] S3, such as Figure 7 As shown, traverse the side wheels except W2-1 and calculate the direction of the line connecting them with the main wheel W1-2;

[0072] S4. Calculate the side wheel loads of other side wheels: Take the W3-2 wheel as an example. Collinear, calculate the influence coefficient of the side wheels ,when Calculate the side wheel load generated when , superimposed on the main wheel load ; Taking W2-2 wheel as an example, its connection direction is Not collinear, ignore the influence of this side wheel.

[0073] S5, accumulate and obtain the first side wheel Time main wheel Equivalent single wheel load ;

[0074] S6, such as Figure 8 As shown, repeat steps S2 to S5 to obtain the first side wheels. ~ Equivalent load at ~ ; Figure 8 A schematic diagram of calculating the equivalent load by traversing other wheels (such as W3-1) as the first side wheels is shown.

[0075] S7, take ~ The maximum value of is taken as the equivalent single wheel load of the main wheel W1-2.

[0076] The present invention discloses a general algorithm for the equivalent single-wheel load of mobile machinery in a port pavement structure. By combining theoretical analysis with numerical solution, corresponding single-wheel load algorithms are designed for multiple types of operating machinery. The present invention can solve the problem of being difficult to calculate the equivalent single-wheel load of new port mobile operating machinery according to current standards in the design of port pavement structures, thus paving the way for the design of pavement structures under the action of special dock machinery.

[0077] Through perfect theoretical analysis and numerical calculation, the present invention proposes a calculation method with clear meaning, wide application range, and easy implementation through programming, thus clearing the technical obstacles for the compilation of calculation software for port engineering pavement structures.

[0078] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0079] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0080] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0081] A person of ordinary skill in the art can understand that: all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0082] Alternatively, if the above-mentioned integrated unit of the present invention is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention can be essentially or partly reflected in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

[0083] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A general algorithm for calculating equivalent single wheel load of mobile machinery in port pavement structure, characterized in that: It includes theoretical analysis, numerical solution, and algorithm design process, specifically: The theoretical analysis is specifically as follows: Through theoretical analysis, the main wheel load is simplified to the normal concentrated force on the boundary of a semi-infinite space body. , obtain the stress distribution formula of the main wheel in the cylindrical coordinate system, and obtain the radial stress generated by the main wheel at point Q at a certain depth z below the horizontal plane ; Set the wheel load of the first side wheel at a certain distance from the main wheel, calculate the stress distribution formula of the first side wheel in the cylindrical coordinate system, and obtain the radial stress generated by the first side wheel at point Q ; Set the wheel loads of the second side wheels at different positions and calculate the stress distribution of the second side wheels in the cylindrical coordinate system; The numerical solution is specifically: The stress states of the main wheel, the first side wheel and the second side wheel in the cylindrical coordinate system are converted into stress states in the Cartesian coordinate system through the direction matrix and superimposed to obtain the final stress state distribution; Solve the characteristic equation of the horizontal stress state matrix after superposition, and obtain the direction of the principal stress, the corresponding characteristic root, that is, the value of the principal stress ; By principal stress value and( ) is used to calculate the incremental ratio of the horizontal tensile stress at point Q of the second side wheelset and take it as the contribution of the bending tensile stress at the bottom of the second side wheelset. If it is a positive value, it indicates that the tensile stress increases, and if it is a negative value, it indicates that the tensile stress decreases; Through the above analysis process, within a certain range from the main wheel, when the second side wheel is in the same direction as the line connecting the main wheel and the first side wheel, the bending tensile stress at the bottom of the pavement structure layer will increase, and when the directions are inconsistent, the bending tensile stress at the bottom of the pavement structure layer will be reduced. Based on the safety perspective, the effect of the second side wheel can be ignored at this time; Based on the above theoretical analysis and numerical solution, the side wheel influence coefficient of mobile machinery with any layout is determined; The algorithm design process is specifically as follows: After the above theoretical analysis and numerical solution, the algorithm for determining the equivalent single wheel load of mobile working machinery of any layout is based on the following steps: S1. Select the main wheel and main wheel load ; S2, select the first side wheel , load , determine the first side wheel and the main wheel Direction of the connection , calculate the first side wheel influence coefficient , calculate the side wheel load generated by the first side wheel , superimposed on the main wheel load ; S3, traverse other side wheels , calculate the other side wheels and the main wheel Direction of the connection ; S4. When the direction or When Side wheel influence coefficient ,when Calculate the side wheel loads generated by the side wheels when , and superimposed on the main wheel load ;when When or and When the directions are inconsistent, ignore the side wheels The impact of S5, accumulate and obtain the first side wheel Time main wheel Equivalent single wheel load ; S6, repeat steps S2 to S5 to obtain the first side wheels are ~ Equivalent load at ~ ; S7, take ~ The maximum value of Equivalent single wheel load.

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