A method for optimizing acceleration amplitude uniformity of a vertical vibration table surface

Abstract

The application discloses a kind of acceleration amplitude uniformity optimization methods for vertical vibration platform table, including steps: based on the principle of deflection distribution, define initial attachment point position;Define the working table boundary range;Simulation analysis is carried out to number module, and the distribution data of uniformity is obtained, and whether the uniformity of excellent area within boundary can be made to be larger is analyzed by comparing working boundary range;In the case where the structural stiffness is fixed, the only method to reduce the acceleration amplitude deviation between two points is to reduce the distance between two points;Repeat the above steps, so that the uniformity within working boundary reaches design target.The application aims to improve the acceleration amplitude uniformity of vibration platform extension table by increasing the number of excitation arm and table attachment points, so that the acceleration amplitude uniformity of the table is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vibration bench test, in particular to an acceleration amplitude uniformity optimization method for a vertical vibration bench platform. BACKGROUND

[0002] Vibration benches are widely used in product structure durability & abnormal sound research, as the installation platform of the measured parts (and tooling), the structural characteristics of the extension platform (referred to as platform) directly affect the vibration loading transmitted to the measured parts.

[0003] In order to ensure that the platform can effectively transmit vibration to the measured parts, many specifications & standard documents have put forward requirements for the acceleration amplitude uniformity of the platform, such as the national standard "JJG 948-2018 Electric Vibration Test System Verification Regulation"; this index restricts the amplitude characteristic difference reflected by the platform at different positions under different vibration frequency excitations, and when the difference is too large, it means that the excitation energy deviation of the corresponding position of the measured part (or different positions of the measured part) is too large; this will have a great influence on the determination of the test conclusion.

[0004] At present, the conventional vertical vibration bench is usually excited by a single point in the center, although the uniformity has been improved with the reinforcement of the spoke and the rib plate, but for the platform with large amplitude size, the uniformity is still not ideal, and the uniformity deviation exceeds 100% under different working conditions; sometimes in order to improve the acceleration amplitude uniformity of a small amount, the stiffness and / or default height of the platform are increased, which causes the self-weight of the platform to increase greatly, which reduces the effective load capacity of the vibration equipment; in order to realize more excellent uniformity index on the large-size platform, the present application is developed. SUMMARY

[0005] The present application aims to provide an acceleration amplitude uniformity optimization method for a vertical vibration bench platform to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme: an acceleration amplitude uniformity optimization method for a vertical vibration bench platform, comprising the following steps:

[0007] Step 1: defining the initial attachment point position based on the deflection distribution equivalence principle;

[0008] Step 2: defining the working platform boundary range;

[0009] Step 3: performing simulation analysis on the logarithmic mode to obtain the distribution data of the uniformity, and comparing with the working boundary range to analyze whether the uniformity of the excellent area within the boundary can be larger;

[0010] Step four: in the case of fixed structural stiffness, the only way to reduce the acceleration amplitude deviation between two points is to reduce the distance between the two points;

[0011] Step five: repeat the above steps three and four to achieve the design target of uniformity within the working boundary.

[0012] Preferably, the boundary range of the workbench in step two is mainly determined according to the installation point distribution range of the measured member or the measured member tool above the workbench, so that all the installation points are within the ideal uniformity range.

[0013] Preferably, the simulation analysis process in step three includes:

[0014] A: use three-dimensional modeling tool software to establish the geometric model of the workbench, and import it into the finite element pre-processing and post-processing software through stp / iges data file format;

[0015] B: perform mesh convergence analysis;

[0016] C: high-precision vibration analysis software is used for analysis during the analysis process, and the calculation result contains the uniformity value, so as to compare with the design target;

[0017] D: shell is used for rapid iteration in the early stage of iteration, and hexahedron and fine tetrahedron elements are used for accurate analysis when the target is to be reached.

[0018] Preferably, when the PCD size cannot reach the design target in step four, the distance between adjacent attachment points can be reduced by increasing the number of attachment points on the same pitch circle, that is, doubling the original number of attachment points.

[0019] Compared with the prior art, the beneficial effects of the present application are:

[0020] The present application aims to improve the acceleration amplitude uniformity of the vibration table extension table by increasing the number of attachment points between the excitation arm and the table, without significantly changing the self-weight and default height of the table, so that the acceleration amplitude uniformity of the table is greatly improved, and the acceleration amplitude uniformity level of the table is improved by at least one level. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the vibration table in embodiment 1 of the present application;

[0022] Figure 2 It is a structural schematic diagram of the excitation arm in embodiment 1 of the present application;

[0023] Figure 3 It is a working interface schematic diagram in embodiment 2 of the present application;

[0024] Figure 4The schematic diagram of the circular boundary in the embodiment 2 of the present application;

[0025] Figure 5 The schematic diagram of the influence of PCD adjustment in the embodiment 2 of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] Embodiment 1: please refer to Figure 1 The vibration bench is composed of a table top, a vibration excitation arm, a connecting flange and a stabilizing arm.

[0028] The table top is the working surface of the entire extension table top, and the specific shape and size thereof are adjusted according to different applications. The attachment point connecting surface is arranged below the vibration excitation arm. In order to control the height of the table top after assembly, the attachment point connecting surface is designed to be concave.

[0029] The vibration excitation arm connects the vibration exciter body and the table top, and has three or more attachment points with the table top. Pin positioning and screw fastening are adopted between the vibration excitation arm and the table top. Holes are opened in the reinforcing rib plate of the vibration excitation arm to meet the installation space of the stabilizing arm and reduce the weight.

[0030] The connecting flange is integrated with the vibration excitation arm and serves as the connection and fixation with the vibration exciter below.

[0031] The stabilizing arm is used to meet the installation space of the vibration excitation arm. The reinforcing rib plate below the table top cannot be fully arranged, which reduces the rigidity of the table top. The stabilizing arm is installed together with the table top through the holes in the reinforcing rib plate of the vibration excitation arm to stabilize the table top and increase the rigidity of the table top. Pin positioning and screw fastening are adopted between the stabilizing arm and the table top.

[0032] In this embodiment, since the vibration excitation arm is connected with the attachment point through a diagonal bracing mechanism, it is required that the reinforcing ribs at the bottom of the table top must avoid the corresponding area (such as Figure 2 , the avoidance area), which reduces the strength in the corresponding direction (such as Figure 2 , the direction indicated by the bidirectional flip arrow). In order to compensate for the strength loss caused by the fact that the avoidance area cannot be arranged with enough reinforcing ribs, a set of detachable reinforcing ribs, i.e., the stabilizing arm, is needed. The stabilizing arm is connected with the table top through threads at both ends and penetrates the hollow area of the diagonal bracing mechanism of the vibration excitation arm.

[0033] Embodiment 2: The present application provides a technical solution: a method for optimizing the acceleration amplitude uniformity of a vertical vibration table top, comprising the following steps:

[0034] Step one: define the initial attachment point position based on the principle of equal deflection distribution; as Figure 3 In the middle, the side length of the table is L=2000mm, the square side length formed by the attachment points is l=1000mm, that is, the attachment point PCD (pitch circle diameter) is about 1400mm; based on this size, the initial version of the model is designed;

[0035] Step two: define the working face boundary range, mainly according to the installation point distribution range of the measured part or the measured part tooling above the table, try to make all the installation points within the ideal uniformity range; generally, the maximum inscribed circle or the maximum octagon of the table is the working boundary range;

[0036] Step three: simulate and analyze the model to obtain the uniformity distribution data, and compare with the working boundary range to analyze whether the uniformity excellent area within the boundary can account for a larger proportion;

[0037] As shown in Figure 4

[0038] ①: Take "E" point as the reference point, the acceleration amplitude of "A, B, C, D" points within the circular boundary is the largest, at this time, the deviation of these four points from the reference point "E" should meet the uniformity design target; if the deviation is too large, the PCD (pitch circle diameter of the four points "A, B, C, D") size (i.e. the distance between point "A" and point "E") should be appropriately reduced; as Figure 5 , intercept the uniformity along the line segment EA, and compare the influence of PCD adjustment; it can be seen that the length of the line segment EA has an influence on the uniformity;

[0039] ②: Adjust the PCD size to make the acceleration amplitude of "F" point equivalent to the reference point "E", which can make the blue area shrink to the boundary to achieve the purpose of a larger proportion of uniformity excellent area;

[0040] Step four: under the condition of fixed structural stiffness, the only way to reduce the acceleration amplitude deviation between two points is to reduce the distance between two points. Therefore, when the design target cannot be achieved by adjusting the PCD size, the distance between adjacent attachment points can be reduced by increasing the number of attachment points on the same pitch circle, generally doubling the original number of attachment points;

[0041] Step five: repeat the above steps three and four until the uniformity within the working boundary reaches the design target.

[0042] In this embodiment, the simulation analysis process in step three includes:

[0043] A: use a three-dimensional modeling tool software to establish a geometric model of the table, and import it into the finite element pre-processing and post-processing software through stp / iges data file format;​

[0044] B: Perform grid convergence analysis, the table model size is 1900mm*1900mm, and the total number of points is required to be not less than 1*105; through comparative analysis, it is found that the grid division with a basic size of 5mm, a minimum size of 3mm and a maximum size of 8mm can achieve analysis accuracy and similar results under hexahedron, tetrahedron and shell elements, and further changing the grid does not obviously improve the results; therefore, this grid parameter is used in the whole table optimization iteration and use process;

[0045] C: High-precision vibration analysis software is used for analysis in the analysis process, and the calculation result contains uniformity value, so as to be compared with the design target;

[0046] D: Shell is used for rapid iteration in the early stage of iteration, and hexahedron and fine tetrahedron elements are used for accurate analysis when the target is to be reached

[0047] After optimization by the above method, the table acceleration amplitude uniformity is greatly improved without significantly changing the self-weight and default height of the table; according to the national standard (JJG 948-2018 Electric Vibration Test System Verification Regulation), clause 4.2.5, the table acceleration amplitude uniformity level can be improved by at least one level.

[0048] Although the embodiments of the present application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for optimizing the acceleration amplitude uniformity of a vertical shaker table, characterized by, The method comprises the steps of: Step 1: defining initial attachment point positions based on the principle of equal deflection distribution; Step 2: defining the workbench boundary range; Step 3: performing simulation analysis on the numerical model to obtain the uniformity distribution data, and comparing the workbench boundary range to analyze whether the excellent uniformity area within the boundary can account for a larger proportion; Step 4: under the condition of fixed structural rigidity, the only way to reduce the acceleration amplitude deviation between two points is to reduce the distance between the two points; Step 5: repeating the above steps 3 and 4 to make the uniformity within the workbench boundary reach the design target.

2. The method for optimizing the acceleration amplitude uniformity of a vertical shaker table according to claim 1, wherein: The workbench boundary range in step 2 is mainly determined according to the installation point distribution range of the measured part or the measured part tooling above the workbench, so that all the installation points are within the ideal uniformity range.

3. The method for optimizing the acceleration amplitude uniformity of a vertical shaker table according to claim 1, wherein: The simulation analysis process in step 3 includes: A: using a three-dimensional modeling tool software to establish a geometric model of the workbench, and importing the stp / iges data file format into the finite element pre-processing and post-processing software; B: performing mesh convergence analysis; C: using high-precision vibration analysis software for analysis during the analysis process, and the calculation results include uniformity values for comparison with the design target; D: using shell for rapid iteration in the early stage of iteration, and using hexahedron and fine tetrahedron elements for accurate analysis when the target is to be reached.

4. The method for optimizing the acceleration amplitude uniformity of a vertical shaker table according to claim 1, wherein: In step 4, when adjusting the PCD size cannot reach the design target, the distance between adjacent attachment points can be reduced by increasing the number of attachment points on the same pitch circle, that is, doubling the original number of attachment points.

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