Special vehicle instrument board cross beam structure and modal identification method

Abstract

The invention discloses a special vehicle instrument board cross beam structure and a modal recognition method.The special vehicle instrument board cross beam structure comprises a cross beam body, the cross beam body comprises a first cross beam bent pipe, a second cross beam bent pipe and a third cross beam bent pipe which are connected in sequence, and fixing supports are arranged at the two ends of the cross beam body; a pipe column installation support is arranged on the first cross beam bent pipe, a lower bent part is arranged on the middle section of the second cross beam bent pipe, a center reinforcing support is arranged on the lower bent part, two short installation stand columns are integrally arranged at the bottom of the lower bent part, and a stand column reinforcing cross beam is arranged between the two short installation stand columns. A U-shaped air conditioner mounting bracket is arranged at the bottom of the third cross beam bent pipe; the device has the advantages of being high in inherent frequency, convenient to install and good in testing effect.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle crossbeam design, and in particular relates to a special vehicle instrument panel crossbeam structure and a modal identification method. Background Art

[0002] Modal identification refers to the process of determining the natural frequency, damping ratio and modal vibration shape of a structure by analyzing its vibration characteristics. Modal identification has a wide range of applications in the engineering field, especially in vibration analysis and fault diagnosis in the automotive, construction and machinery industries.

[0003] Modal identification is mainly used in the field of engineering vibration, especially in automotive NVH (noise, vibration and comfort) analysis. Through modal identification, the resonance area of ​​the structure can be understood, providing guidance for structural design and avoiding the occurrence of resonance. In addition, modal identification can also be used for fault diagnosis and optimization design to improve the stability and reliability of the structure.

[0004] The principle of modal identification is based on modal analysis, which is to calculate the natural vibration characteristics of the structure. The natural frequency, damping ratio and modal vibration shape of the structure are obtained through finite element calculation or test methods. The finite element calculation method calculates through mathematical models, while the test method identifies parameters by collecting system input and output signals.

[0005] The significance of modal identification is to understand the resonance area of ​​the structure, provide guidance for structural design, and avoid the occurrence of resonance. In addition, modal identification can also be used for fault diagnosis and optimization design to improve the stability and reliability of the structure. In practical applications, the output amplitude phase or real part and imaginary part can be selected as needed to determine the modal frequency of interest.

[0006] The shortcomings of the existing technology are that special vehicles have increasingly higher requirements for body durability and seismic resistance due to complex working conditions, while the existing vehicle structure is fixed and the natural frequency is relatively stable, making it difficult to improve; the existing traditional special vehicle crossbeams are usually a straight rod structure with a long column structure, and the long column structure needs to be installed in sections, which makes the installation complicated; it is difficult to accurately test the modal performance of the vehicle crossbeam. Summary of the invention

[0007] The purpose of the present invention is to provide a special vehicle dashboard crossbeam structure and a modal identification method in view of the problems existing in the prior art. The scheme has the advantages of high natural frequency, easy installation and good test effect. The structure has good anti-bending and anti-torsion properties and is suitable for complex road conditions.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a special vehicle dashboard beam structure and modal identification method, including a beam body, the beam body includes beam bend pipe 1, beam bend pipe 2, and beam bend pipe 3 connected in sequence, fixed brackets are arranged at both ends of the beam body, a column mounting bracket is arranged on the beam bend pipe 1, a lower bend portion is arranged in the middle section of the beam bend pipe 2, a central reinforcement bracket is arranged on the lower bend portion, two short mounting columns are integrally arranged at the bottom of the lower bend portion, a column reinforcement beam is arranged between the two short mounting columns, and a U-shaped air conditioner mounting bracket is arranged at the bottom of the beam bend pipe 3.

[0009] In the above scheme, the crossbeam body includes crossbeam bend pipe 1, crossbeam bend pipe 2, and crossbeam bend pipe 3. The three-section bend pipe structure is used to effectively improve the first-order bending mode and first-order torsion mode of the instrument panel crossbeam structure, improve the system's natural frequency, and effectively improve the system's safety performance. The fixed brackets at both ends of the crossbeam body are used to connect the crossbeam to the vehicle body, and the column mounting bracket is used to connect the steering column. A lower bend is set in the middle section of the crossbeam bend pipe 2 to facilitate the reduction of the length of the installation column. Different from the traditional long column structure, the long column structure needs to be installed in sections, while the integrated short column form can be installed once, which is convenient and quick. The use of a short column structure helps to eliminate the bending characteristics of the long column. A central reinforcement bracket is set on the lower bend to facilitate component connection, and a column reinforcement beam is set to enhance the stability of the short installation column structure. An air conditioner mounting bracket is set on the crossbeam bend pipe 3 to facilitate the installation and positioning of the air conditioner.

[0010] Furthermore, the pipe column mounting bracket includes a pipe column upper mounting plate and a pipe column lower mounting plate, and the pipe column mounting bracket is connected to a pipe column reinforcement plate.

[0011] The column upper mounting plate, column lower mounting plate and column reinforcement plate form a steering column installation space, the column mounting bracket is connected to the crossbeam body by welding, and the steering column connection is strengthened by the column reinforcement plate.

[0012] Furthermore, the bending angle of the first crossbeam bend is 155°-165°, the bending angles at both ends of the lower bend are 130°-140°, and the bending angle of the third crossbeam bend is 140°-150°.

[0013] By bending the crossbeam bend one, crossbeam bend two, and crossbeam bend three at corresponding angles, the bending and torsional resistance of the overall structure can be enhanced. The concentrated mass angle of crossbeam bend two is 130°-140°, which can increase the system's natural frequency by 10-15Hz, and has a positive effect on the overall stability of the dashboard crossbeam.

[0014] Furthermore, the thickness of the crossbeam bend tube 2 is 10±1 mm, and the thickness of the crossbeam bend tube 1 and the crossbeam bend tube 3 are both 8±1 mm.

[0015] The variable cross-section design has a certain effect on the stability of the dashboard beam. The second crossbeam bend in the middle section of the beam body is thickened to improve the overall rigidity.

[0016] Furthermore, a reinforcement member is provided between the cross beam body and the pipe column mounting bracket, and a column reinforcement plate is provided on the short mounting column.

[0017] A reinforcement piece is provided to enhance the connection stability between the crossbeam body and the pipe column mounting bracket, and a column reinforcement plate is provided to enhance the fastening effect of the short mounting column.

[0018] Furthermore, a lower mounting plate is provided at the bottom of the crossbeam bend tube 1, and the lower mounting plate is located at the bottom of the fixed bracket.

[0019] The connection stability between the crossbeam body and the vehicle body is strengthened by the lower side mounting plate.

[0020] Furthermore, the central reinforcing bracket includes a middle stabilizing frame, a connecting groove is opened in the middle of the middle stabilizing frame, a middle section bent plate of the cross beam is arranged on the lower bent portion, and the middle section bent plate of the cross beam passes through the connecting groove.

[0021] The middle stabilizing frame is U-shaped, and connecting holes and grooves are provided on the curved plate in the middle section of the crossbeam to facilitate the connection of components.

[0022] Furthermore, the column mounting bracket is provided with a mounting hole for connecting the steering column, and the column mounting bracket includes a mounting groove for accommodating the steering column.

[0023] The steering column is connected and fastened through the mounting holes on the column mounting bracket, and the steering column is accommodated and protected by the column mounting bracket.

[0024] A modal identification method for the above-mentioned special vehicle instrument panel crossbeam structure and modal identification method comprises the following steps: 1. setting at least 5 measuring points on the crossbeam body and numbering them 1-5 in sequence; arranging acceleration sensors at measuring points 1-5, testing the displacement and acceleration value of each measuring point, and determining the displacement vibration mode of the measuring point; 2. respectively exciting each measuring point, testing the acceleration and displacement of each point; when the excitation directions of the measuring points on both sides are the same direction excitation, testing the lateral bending mode of the crossbeam structure, and outputting the displacement vibration mode of each measuring point; when the excitation directions of the measuring points on both sides are the opposite direction excitation, testing the torsion mode of the crossbeam structure, and outputting the displacement vibration mode of each measuring point.

[0025] In the above scheme, step 1 sets 5 measuring points on the main body of the beam and numbers them respectively, and sets acceleration sensors to facilitate testing the displacement and acceleration values ​​of each point and determining the displacement vibration mode of the measuring point; step 2 tests the acceleration and displacement of each point by respectively exciting them, tests the lateral bending mode by exciting each measuring point in the same direction; and tests the torsional mode by exciting the measuring points on both sides of the beam structure in the opposite direction, which is convenient for testing.

[0026] A modal identification method for the above-mentioned special vehicle dashboard crossbeam structure and modal identification method comprises the following steps: 1. installing a steering column and a steering wheel, and evenly arranging a plurality of acceleration sensors on the outer ring of the steering wheel; 2. testing the lateral and longitudinal motion modes of the steering wheel; when testing the lateral motion mode, respectively exciting the steering wheel in the 9 o'clock and 3 o'clock directions, and the excitation direction is lateral; respectively outputting the acceleration curve and motion displacement curve of each measuring point in the 9 o'clock and 3 o'clock directions, and correspondingly superimposing and comparing the curves in the two directions to identify the lateral motion mode; when testing the longitudinal motion mode, respectively exciting the steering wheel in the 12 o'clock and 6 o'clock directions, and the excitation direction is longitudinal; outputting the acceleration curve and motion displacement curve of the 12 o'clock and 6 o'clock directions, and correspondingly superimposing and comparing the curves in the two directions to identify the longitudinal motion mode.

[0027] In the above scheme, in step 1, the acceleration sensor is evenly arranged at 12 points according to the hands, and the acceleration sensor can be connected to the steering wheel by tape. In step 2, by testing the lateral and longitudinal motion modes, the acceleration curve and the motion displacement curve under the two directional excitation conditions are tested respectively in the two modes, the superimposed curve is processed by peak-to-peak value, the curve overlap area and the peak overlap area under the two directional excitation are compared, the motion modal characteristics are identified, and the corresponding modal frequency is tested.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting three sections of crossbeam bends to strengthen the overall rigidity of the crossbeam main structure, the bending and torsion resistance of the overall structure can be enhanced, the natural frequency of the system can be increased, and the safety performance of the system can be effectively improved, and the structure is simple; 2. By setting a lower bent portion in the middle of the beam body, the short mounting column is connected in an integrated manner, which has a simple structure and is easy to install; 3. By selecting measuring points on the main body of the beam, the transverse bending mode and transverse torsion mode frequency tests of the beam structure are carried out, with good test results and simple operation; 4. By installing the steering column and steering wheel on the main body of the crossbeam, the lateral and longitudinal motion modes of the steering wheel are tested, and the modal frequencies of the steering wheel when subjected to various excitations are identified. The test effect is good and the operation is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A structural stereogram of a special vehicle instrument panel cross beam structure according to embodiment 1 of the present invention; Figure 2 This is a structural schematic diagram of a special vehicle instrument panel crossbeam structure according to embodiment 1 of the present invention; Figure 3 A top view of the structure of the pipe column mounting bracket in Example 1 of the present invention; Figure 4 A structural stereogram of an air conditioner mounting bracket in Embodiment 1 of the present invention; Figure 5 is a position diagram of the acceleration sensor in embodiment 1 of the present invention; Figure 6 Schematic diagram of the excitation direction in the lateral motion mode in Example 2 of the present invention; Figure 7 Schematic diagram of the excitation direction in the longitudinal motion mode in Example 2 of the present invention; In the figure: 1. Crossbeam bend tube 1; 2. Crossbeam bend tube 2; 3. Crossbeam bend tube 3; 4. Fixed bracket; 5. Upper mounting plate of pipe column; 6. Lower mounting plate of pipe column; 7. Pipe column reinforcement plate; 8. Lower bend; 9. Middle stabilizing frame; 10. Short mounting column; 11. Column reinforcement beam; 12. Air conditioner mounting bracket; 13. Reinforcement piece; 14. Column reinforcement plate; 15. Lower side mounting plate; 16. Connecting groove; 17. Middle section bend plate of crossbeam; 18. Mounting groove; 19. Air conditioner mounting reinforcement plate; 20. Acceleration sensor; 21. Steering wheel. DETAILED DESCRIPTION

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms front, back, left, right, etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, or are the directions or positional relationships in which the invented product is usually placed when used. They are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Example 1

[0031] like Figure 1-4As shown, a special vehicle dashboard crossbeam structure and modal identification method include a crossbeam body, the crossbeam body includes a crossbeam bend pipe 1, a crossbeam bend pipe 2, and a crossbeam bend pipe 3 connected in sequence, fixed brackets 4 are arranged at both ends of the crossbeam body, a column mounting bracket is arranged on the crossbeam bend pipe 1, a lower bend portion 8 is arranged in the middle section of the crossbeam bend pipe 2, a central reinforcement bracket is arranged on the lower bend portion 8, two short mounting columns 10 are integrally arranged at the bottom of the lower bend portion 8, a column reinforcement crossbeam 11 is arranged between the two short mounting columns 10, and a U-shaped air conditioner mounting bracket 12 is arranged at the bottom of the crossbeam bend pipe 3.

[0032] In the above scheme, the crossbeam body includes crossbeam bend pipe 1, crossbeam bend pipe 2, and crossbeam bend pipe 3. The three-section bend pipe structure is used to effectively improve the first-order bending mode and first-order torsion mode of the instrument panel crossbeam structure, improve the system's natural frequency, and effectively improve the system's safety performance. The fixed brackets 4 at both ends of the crossbeam body are used to connect the crossbeam to the vehicle body, and the column mounting bracket is used to connect the steering column. The middle section of the crossbeam bend pipe 2 is provided with a lower bend 8 to facilitate the reduction of the length of the installation column. Different from the traditional long column structure, the long column structure needs to be installed in sections, while the integrated short column form can be installed once, which is convenient and fast. The use of a short column structure helps to eliminate the bending characteristics of the long column. A central reinforcement bracket is provided on the lower bend 8 to facilitate component connection, and a column reinforcement crossbeam 11 is provided to enhance the stability of the short installation column 10 structure. An air conditioner mounting bracket 12 is provided on the crossbeam bend pipe 3 to facilitate the installation and positioning of the air conditioner.

[0033] The main function is fixed installation. Large-angle bending is beneficial to improving the bending mode and torsional mode of the overall structure, and improving the vibration stability and durability of the overall structure.

[0034] The integrated bracket is 100mm shorter than the traditional bracket. This design is integrated and can be installed successfully in the passenger compartment at one time. The integrated short bracket design is conducive to improving the system's natural mode and seismic performance. The three-section curved pipe structure is designed, which can effectively improve the first-order bending mode and first-order torsion mode of the instrument panel beam structure, increase the system's natural frequency, and effectively improve the system's safety performance.

[0035] The lower part of the crossbeam elbow 3 is an air conditioner mounting bracket 12, which is fixed by inner and outer multilayer plates and is welded by two, three and four layers.

[0036] An air conditioner mounting reinforcement plate 19 is provided on the air conditioner mounting bracket 12 .

[0037] Furthermore, the pipe column mounting bracket comprises a pipe column upper mounting plate 5 and a pipe column lower mounting plate 6 , and the pipe column mounting bracket is connected to a pipe column reinforcement plate 7 .

[0038] The column upper mounting plate 5, the column lower mounting plate 6 and the column reinforcement plate 7 form a steering column mounting space. The column mounting bracket is connected to the crossbeam body by welding, and the steering column connection is strengthened by the column reinforcement plate 7.

[0039] In order to improve the vertical mode of the steering column, the thickness of the steering column mounting structure is 2-3mm to increase the mounting rigidity. The steering column mounting structure is connected to the instrument panel elbow through welding points and gap welding. Holes and grooves can be opened on the column reinforcement plate 7 to connect the steering column. The column mounting bracket and the center reinforcement bracket structure adopt a symmetrical structure, with small mass at both ends and large mass in the middle, to increase the overall structural stability.

[0040] Furthermore, the bending angle of the crossbeam bend pipe 1 is 155°-165°, the bending angles at both ends of the lower bend 8 are 130°-140°, and the bending angle of the crossbeam bend pipe 3 is 140°-150°.

[0041] By bending the crossbeam bend 1, crossbeam bend 2, and crossbeam bend 3 at corresponding angles, the bending and torsional resistance of the overall structure can be enhanced. The concentrated mass angle of crossbeam bend 2 is 130°-140°, which can increase the system's natural frequency by 10-15Hz, and has a positive effect on the overall stability of the dashboard beam.

[0042] The bending directions of the crossbeam bend pipe 1 and the crossbeam bend pipe 3 are opposite. Preferably, the crossbeam bend pipe 1 has a bending angle of 160°, two 135° corners are respectively arranged at both ends of the lower bend portion 8, and the crossbeam bend pipe 3 has a bending angle of 145°.

[0043] Furthermore, the thickness of the crossbeam bend pipe 2 is 10±1 mm, and the thickness of the crossbeam bend pipe 1 and the crossbeam bend pipe 3 are both 8±1 mm.

[0044] The variable cross-section design has a certain effect on the stability of the instrument panel crossbeam. The crossbeam bend 2 in the middle section of the crossbeam body is thickened to improve the overall rigidity.

[0045] Furthermore, a reinforcement member 13 is provided between the cross beam body and the pipe column mounting bracket, and a column reinforcement plate 14 is provided on the short mounting column 10 .

[0046] A reinforcement member 13 is provided to enhance the connection stability between the cross beam body and the pipe column mounting bracket, and a column reinforcement plate 14 is provided to enhance the fastening effect of the short mounting column 10 .

[0047] The reinforcement member 13 comprises a tube body and a plate body structure, and a short column reinforcement bracket is integrated in the lower bent section to strengthen the short installation column 10 to facilitate integrated installation.

[0048] Furthermore, a lower mounting plate 15 is provided at the bottom of the crossbeam bend pipe 1, and the lower mounting plate 15 is located at the bottom of the fixing bracket 4.

[0049] The connection stability between the cross beam body and the vehicle body is enhanced by the lower mounting plate 15 .

[0050] The lower mounting plate 15 can be used to connect to the support structure.

[0051] Furthermore, the central reinforcing bracket includes a middle stabilizing frame 9 , a connecting groove 16 is provided in the middle of the middle stabilizing frame 9 , a middle section bent plate 17 of the cross beam is provided on the lower bent portion 8 , and the middle section bent plate 17 of the cross beam is provided through the connecting groove 16 .

[0052] The middle stabilizing frame 9 is U-shaped, and a connecting hole groove is provided on the middle curved plate 17 of the cross beam to facilitate the connection of components.

[0053] Furthermore, a mounting hole for connecting the steering column is provided on the column mounting bracket, and the column mounting bracket includes a mounting groove 18 for accommodating the steering column.

[0054] The steering column is connected and fastened through the mounting holes on the column mounting bracket, and the steering column is accommodated and protected by the column mounting bracket.

[0055] like Figure 5 As shown, a modal identification method of the above-mentioned special vehicle instrument panel crossbeam structure and modal identification method includes the following steps: 1. Setting at least 5 measuring points on the crossbeam body and numbering them 1-5 in sequence; arranging acceleration sensors 20 at the measuring points 1-5, testing the displacement and acceleration value of each measuring point, and determining the displacement vibration type of the measuring point; 2. Exciting each measuring point separately, testing the acceleration and displacement of each point; when the excitation directions of the measuring points on both sides are the same direction excitation, testing the lateral bending mode of the crossbeam structure, and outputting the displacement vibration type of each measuring point; when the excitation directions of the measuring points on both sides are the opposite direction excitation, testing the torsional mode of the crossbeam structure, and outputting the displacement vibration type of each measuring point.

[0056] In the above scheme, step 1 sets 5 measuring points on the main body of the beam and numbers them 1-5 respectively. Acceleration sensor No. 3 is located at the lower bend 8 in the middle of the main body of the beam. Acceleration sensor 20 is set to facilitate testing the displacement and acceleration values ​​of each point and determining the displacement vibration mode of the measuring point. Step 2 tests the acceleration and displacement of each point by respectively exciting them, and tests the lateral bending mode by exciting each measuring point in the same direction. The torsional mode is tested by applying opposite direction excitation to the measuring points on the left and right sides of the beam structure, which is convenient for testing.

[0057] Before the test, the main body of the crossbeam can be connected to the car body for fixing, and a force hammer sensor is used to excite each measuring point. Five measuring points are set in sequence at the end of the crossbeam bend tube 1, the bending vertex of the crossbeam bend tube 1, the lower bend 8, the corner of the crossbeam bend tube 2, and the bending vertex of the crossbeam bend tube 1. By detecting each characteristic point, the overall structural characteristics of the crossbeam structure are reflected. After testing, compared with the crossbeam without a curved structure arranged horizontally on the instrument panel, this solution has a modal increase of 10-15Hz. Example 2

[0058] like Figure 6-7 As shown, the modal identification method of a special vehicle instrument panel cross beam structure of this embodiment is further optimized on the basis of a special vehicle instrument panel cross beam structure in Example 1: A modal identification method for the above-mentioned special vehicle dashboard crossbeam structure and modal identification method comprises the following steps: 1. installing a steering column and a steering wheel 21, and evenly arranging a plurality of acceleration sensors 20 on the outer ring of the steering wheel 21; 2. testing the lateral and longitudinal motion modes of the steering wheel 21; when testing the lateral motion mode, respectively exciting the steering wheel 21 at 9 o'clock and 3 o'clock directions, and the excitation direction is lateral; respectively outputting the acceleration curve and motion displacement curve of each measuring point at 9 o'clock and 3 o'clock directions, correspondingly superimposing and comparing the curves in the two directions, and identifying the lateral motion mode; when testing the longitudinal motion mode, respectively exciting the steering wheel 21 at 12 o'clock and 6 o'clock directions, and the excitation direction is longitudinal; outputting the acceleration curve and motion displacement curve at 12 o'clock and 6 o'clock directions, correspondingly superimposing and comparing the curves in the two directions, and identifying the longitudinal motion mode.

[0059] In the above scheme, in step 1, the acceleration sensor 20 is evenly arranged at 12 points according to the hands, and the acceleration sensor 20 can be connected to the steering wheel by tape. In step 2, by testing the lateral and longitudinal motion modes, the acceleration curve and the motion displacement curve under the two-directional excitation are tested respectively in the two modes, the superimposed curve is processed by peak-to-peak value, the curve overlap area and the peak overlap area under the two-directional excitation are compared, the motion modal characteristics are identified, and the corresponding modal frequency is tested.

[0060] Before the test, the main body of the crossbeam can be connected to the vehicle body for fixing, and the steering column and the steering wheel 21 can be installed on the crossbeam structure before the test. During the test, a hammer sensor is used to stimulate the steering wheel 21. Compared with the unbent structure of the instrument panel crossbeam, the steering wheel 21 is installed, and the above steps 1-2 are repeated. The two test modes are compared. The transverse bending arrangement and design structure of the crossbeam structure in this solution have a positive effect on the transverse and longitudinal modes of the steering wheel 21, which can increase the transverse and longitudinal modes by 10-15Hz.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A special vehicle instrument panel crossbeam structure, characterized in that: It includes a beam main body, which includes beam bend pipe 1, beam bend pipe 2, and beam bend pipe 3 connected in sequence, fixed brackets are arranged at both ends of the beam main body, beam bend pipe 1 is provided with a pipe column mounting bracket, a lower bend portion is arranged in the middle section of beam bend pipe 2, a central reinforcement bracket is arranged on the lower bend portion, two short mounting columns are integrally arranged at the bottom of the lower bend portion, a column reinforcement beam is arranged between the two short mounting columns, and a U-shaped air conditioner mounting bracket is arranged at the bottom of beam bend pipe 3.

2. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: The pipe column mounting bracket comprises a pipe column upper mounting plate and a pipe column lower mounting plate, and the pipe column mounting bracket is connected to a pipe column reinforcement plate.

3. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: The bending angle of the first crossbeam bend is 155°-165°, the bending angles at both ends of the lower bend are 130°-140°, and the bending angle of the third crossbeam bend is 140°-150°.

4. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: The thickness of the second crossbeam bend is 10±1 mm, and the thickness of the first crossbeam bend and the third crossbeam bend are both 8±1 mm.

5. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: A reinforcement piece is arranged between the cross beam body and the pipe column mounting bracket, and a column reinforcement plate is arranged on the short mounting column.

6. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: A lower mounting plate is provided at the bottom of the crossbeam bent pipe 1, and the lower mounting plate is located at the bottom of the fixing bracket.

7. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: The central reinforcement bracket comprises a middle stabilizing frame, a connecting groove is provided in the middle of the middle stabilizing frame, a middle section bent plate of the cross beam is provided on the lower bent portion, and the middle section bent plate of the cross beam passes through the connecting groove.

8. The special vehicle instrument panel cross beam structure according to claim 1, characterized in that: The column mounting bracket is provided with a mounting hole for connecting the steering column, and the column mounting bracket includes a mounting groove for accommodating the steering column.

9. A method for modal identification of a crossbeam structure of a special vehicle dashboard as claimed in any one of claims 1 to 8, characterized in that The method comprises the following steps:

1. setting at least 5 measuring points on the main body of the beam and numbering them 1-5 in sequence; arranging acceleration sensors at the measuring points 1-5, testing the displacement and acceleration values ​​of each measuring point, and determining the displacement vibration mode of the measuring point; 2. exciting each measuring point respectively, testing the acceleration and displacement of each point; when the excitation directions of the measuring points on both sides are the same direction excitation, testing the lateral bending mode of the beam structure, and outputting the displacement vibration mode of each measuring point; when the excitation directions of the measuring points on both sides are the opposite direction excitation, testing the torsional mode of the beam structure, and outputting the displacement vibration mode of each measuring point.

10. A modal identification method for a special vehicle instrument panel crossbeam structure as claimed in any one of claims 1 to 8, characterized in that The method comprises the following steps:

1. installing a steering column and a steering wheel, and evenly arranging a plurality of acceleration sensors on the outer ring of the steering wheel; 2. testing the lateral and longitudinal motion modes of the steering wheel; when testing the lateral motion mode, respectively exciting the steering wheel at 9 o'clock and 3 o'clock directions, and the excitation direction is lateral; respectively outputting the acceleration curve and motion displacement curve of each measuring point at 9 o'clock and 3 o'clock directions, correspondingly superimposing and comparing the frequencies of the curves in the two directions, and identifying the lateral motion mode; when testing the longitudinal motion mode, respectively exciting the steering wheel at 12 o'clock and 6 o'clock directions, and the excitation direction is longitudinal; outputting the acceleration curve and motion displacement curve at 12 o'clock and 6 o'clock directions, correspondingly superimposing and comparing the frequencies of the curves in the two directions, and identifying the longitudinal motion mode.

Images