Fatigue analysis method of diaphragm compressor

Abstract

The invention discloses a fatigue analysis method for a diaphragm compressor. The fatigue analysis method comprises the following steps: establishing a finite element model; setting material attributes; carrying out grid division; load and constraint setting; and fatigue solving. The invention relates to a fatigue analysis method of a diaphragm compressor. The method comprises the steps of finite element model establishment, material attribute setting, mesh generation and load and constraint setting. Fatigue solving is conducted, fatigue damage, the fatigue safety coefficient and the service life can be obtained through simulation calculation, evaluation of the fatigue service life of a cylinder cover, a cylinder body and other core components of the diaphragm compressor is achieved, the reliability in the actual using process is ensured, and the fatigue analysis method is easy and convenient to operate, high in result reliability and high in practicability.

Description

Technical Field

[0001] The invention relates to the technical field of diaphragm compressors, and in particular to a fatigue analysis method for diaphragm compressors. Background Art

[0002] For high-pressure diaphragm compressors, due to the movement characteristics of diaphragm compressors, cyclic stress under high pressure must be considered to avoid fatigue damage to the cylinder head, cylinder body and other core components caused by long-term operation. Fatigue damage caused by high-pressure cyclic stress not only affects the normal operation of the diaphragm compressor, but sometimes causes compressed gas leakage, and sometimes causes serious safety accidents such as fire and explosion, resulting in personal injury and property loss, endangering economic security. Therefore, it is very necessary to conduct cyclic stress fatigue analysis on high-pressure diaphragm compressors. Summary of the invention

[0003] The present invention provides a fatigue analysis method for a diaphragm compressor, thereby solving the blank in the prior art of predicting fatigue failure of diaphragm compressors.

[0004] In order to solve the above technical problems, the present invention provides a fatigue analysis method for a diaphragm compressor, comprising the following steps:

[0005] (1) Establishing a finite element model: Importing the diaphragm compressor assembly model into the simulation software, simplifying it, setting binding contact or coupling between the components, and constructing a finite element model;

[0006] (2) Material property setting: inputting the material properties of each part in the finite element model obtained in step (1) into the simulation calculation software;

[0007] (3) Meshing: Meshing the finite element model using tetrahedral meshes and structured meshes;

[0008] (4) Load and constraint setting: Perform force analysis on the finite element model to obtain force information, then add load to each loading point, linearly superimpose the corresponding unit load stress distribution and force load spectrum to obtain the stress-strain response;

[0009] (5) Fatigue solution: Define material parameters and number of cycles in fatigue analysis software, obtain the SN life curve of the corresponding material, and then perform linear damage accumulation simulation calculation based on the stress-strain response to obtain fatigue damage, fatigue safety factor and life after analysis and processing.

[0010] In a preferred embodiment of the present invention, in step (1), the simplified content includes:

[0011] The cylinder head and valve plate are simplified into an integrated structure;

[0012] The cylinder body, oil distribution plate and guide ring are simplified into an integrated structure;

[0013] Simplify the screw to a screw;

[0014] The cooling water channels in the cylinder head and the cylinder block are simplified into an integrated structure with the cylinder head and the cylinder block respectively.

[0015] In a preferred embodiment of the present invention, in step (2), the material properties include density, Poisson's ratio, Young's modulus, tensile yield strength and compressive yield strength.

[0016] In a preferred embodiment of the present invention, in step (3), the method of dividing the grid is: dividing the regular area in the finite element model into a structured grid, and dividing the area outside the regular area into a tetrahedral grid.

[0017] In a preferred embodiment of the present invention, the regular area includes a pressing tube or a pressing plate.

[0018] The beneficial effects of the present invention are as follows: a fatigue analysis method for a diaphragm compressor of the present invention can simulate and calculate fatigue damage, fatigue safety factor and life by establishing a finite element model, setting material properties, meshing, setting loads and constraints, and fatigue solving, so as to realize the evaluation of the fatigue life of the cylinder head, cylinder body and other core components of the diaphragm compressor, and ensure the reliability during actual use. The fatigue analysis method is easy to operate, has high reliability of results, and is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a process flow diagram of a fatigue analysis method for a diaphragm compressor of the present invention;

[0020] Figure 2 is a schematic diagram of the diaphragm compressor assembly model shown;

[0021] Figure 3 is a schematic diagram of the internal structure of the finite element model obtained by simplifying the diaphragm compressor assembly model shown;

[0022] Figure 4 is a schematic diagram of the three-dimensional structure of the finite element model shown;

[0023] Figure 5 is a schematic diagram of the finite element model after meshing;

[0024] Figure 6 is a schematic diagram of the force analysis of the cylinder head in the finite element model shown;

[0025] The markings of the components in the accompanying drawings are as follows:

[0026] 100. Diaphragm compressor assembly model;

[0027] 110. Cylinder block; 120. Cylinder head; 130. Valve plate; 140. Oil plate; 150. Valve; 160. Bolts; 171. Intake pipe, 172. Exhaust pipe;

[0028] 200. Finite element model;

[0029] 210. Finite element cylinder body; 220. Finite element cylinder head; 230. Finite element pressure pipe; 240. Finite element fastening bolts; 250. Finite element gas valve. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0031] See also Figure 1-6 , the embodiment of the present invention includes:

[0032] The present invention discloses a fatigue analysis method for a diaphragm compressor, which specifically comprises the following steps:

[0033] (1) Establishing a finite element model: Importing the diaphragm compressor assembly model into simulation software, such as Workbench software, simplifying the diaphragm compressor assembly model, and setting binding contact or coupling between components to construct a finite element model to be analyzed.

[0034] High pressure diaphragm compressor assembly Figure 2 As shown. The high-pressure diaphragm compressor assembly has a complex structure. In order to reduce the calculation time, it should be simplified before constructing the finite element analysis geometric model. The specific simplification content is as follows:

[0035] Since the cylinder head 120 and the valve plate 130 bear the axial gas force together, the cylinder head 120 and the valve plate 130 are simplified into an integrated structure;

[0036] Taking the cylinder head 120 and the cylinder block 110 as an example, the chamfers and fillets at the openings of other components need to be ignored to reduce the number of grids, and the cylinder block 110 and the oil distribution plate 140 are simplified into an integrated structure;

[0037] The oil pipeline, interface, plunger, plunger sleeve, positioning studs, etc. on the cylinder body are also simplified into an integrated structure with the cylinder body;

[0038] Since the function of the screws on the cylinder cover 120 is the same as that of the bolts 160 , the screws (not shown) on the upper surface of the cylinder cover 120 are simplified as screws.

[0039] The finite element model obtained after simplifying the diaphragm compressor assembly model is as follows: Figure 3shown.

[0040] (2) Material property setting: For the finite element model obtained after simplification in step (1), the material properties of each part are input into the simulation calculation software, and the material corresponding to the structure of each part of the finite element model is assigned.

[0041] Specifically, the finite element model includes a finite element cylinder block 210, a finite element cylinder head 220, a finite element pressure pipe 230, a finite element fastening bolt 240 and a finite element gas valve 250, and the material properties of each component include density, Poisson's ratio, Young's modulus, tensile yield strength and compressive yield strength.

[0042] (3) Meshing: Importing mesh information, such as mesh size and meshing method, and meshing the finite element model using tetrahedral meshes and structured meshes.

[0043] Since there are cylindrical radial opening structures in the finite element model and the phenomenon of vertical intersection of opening channels, it is difficult to use structured meshing. Therefore, structured meshes are divided in relatively regular areas such as pressure pipes and pressure plates, and tetrahedral meshes are divided in other areas. The graphics after division are as follows: Figure 4 shown.

[0044] (4) Setting loads and constraints: Perform force analysis on the simplified finite element model of the diaphragm compressor assembly model to obtain the corresponding force information, as follows: Figure 5 As shown, based on the obtained force information, load is added to each loading point, and the corresponding unit load stress distribution and force load spectrum are linearly superimposed to obtain the stress-strain response.

[0045] (5) Fatigue solution: In the fatigue analysis software Workbench, the material parameters and cycle times of the cylinder head, cylinder body and other components of the high-pressure diaphragm compressor are defined, and the SN life curve of the corresponding material is obtained. According to the stress-strain response obtained in step (4) and the SN life curve, a linear damage accumulation simulation calculation is performed to obtain the fatigue damage, fatigue safety factor and life after analysis and processing.

[0046] The present invention provides a fatigue analysis method for a diaphragm compressor. In the early stage of diaphragm compressor development, fatigue analysis can replace tests to a large extent, shorten the research and development cycle of high-pressure diaphragm compressors, and avoid the accidental and random nature of test results.

[0047] In the absence of actual measured data, by reasonably simplifying the model and performing force analysis in the fatigue analysis software and loading the high-pressure diaphragm compressor, and then using the fatigue analysis software, the fatigue damage, fatigue safety factor and life can be quickly obtained through simulation calculations, thereby conveniently realizing the fatigue life evaluation of the cylinder head, cylinder body and other core components of the high-pressure diaphragm compressor, ensuring reliability during actual use.

[0048] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A fatigue analysis method for a diaphragm compressor, characterized in that: The steps include: (1) Establishing a finite element model: Importing the diaphragm compressor assembly model into the simulation software, simplifying it, setting binding contact or coupling between the components, and constructing a finite element model; (2) Material property setting: inputting the material properties of each part in the finite element model obtained in step (1) into the simulation calculation software; (3) Meshing: Meshing the finite element model using tetrahedral meshes and structured meshes; (4) Load and constraint setting: Perform force analysis on the finite element model to obtain force information, then add load to each loading point, linearly superimpose the corresponding unit load stress distribution and force load spectrum to obtain the stress-strain response; (5) Fatigue solution: Define material parameters and number of cycles in fatigue analysis software, obtain the SN life curve of the corresponding material, and then perform linear damage accumulation simulation calculation based on the stress-strain response to obtain fatigue damage, fatigue safety factor and life after analysis and processing.

2. A fatigue analysis method for a diaphragm compressor according to claim 1, characterized in that: In step (1), the simplified content includes: The cylinder head and valve plate are simplified into an integrated structure; The cylinder body, oil distribution plate and guide ring are simplified into an integrated structure; Simplify the screw to a screw; The cooling water channels in the cylinder head and the cylinder block are simplified into an integrated structure with the cylinder head and the cylinder block respectively.

3. A fatigue analysis method for a diaphragm compressor according to claim 1, characterized in that: In step (2), the material properties include density, Poisson's ratio, Young's modulus, tensile yield strength and compressive yield strength.

4. A fatigue analysis method for a diaphragm compressor according to claim 1, characterized in that: In step (3), the method of dividing the grid is: dividing the regular area in the finite element model into a structured grid, and dividing the area outside the regular area into a tetrahedral grid.

5. A fatigue analysis method for a diaphragm compressor according to claim 4, characterized in that: The regular area includes a press tube or a press plate.

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