Lubricating oil pump fatigue life calculation method based on finite element software

Abstract

The invention belongs to the field of technical simulation, and relates to a fatigue life calculation method in a lubricating oil pump design process, in particular to a method for carrying out simulation calculation on a lubricating oil pump in design by utilizing finite element software with a fatigue life analysis function, carrying out simulation according to an actual test or working condition, and carrying out optimization design on a lubricating oil pump structure according to a calculation result. Relates to a lubricating oil pump fatigue life calculation method based on finite element software. Fatigue life simulation is carried out on the newly-designed lubricating oil pump by using a numerical simulation method to find out structural design weak points, and a basis is provided for optimal design of the structure and improvement of product reliability. The inherent frequency, the vibration mode, the response, the damage and the service life of the lubricating oil pump are obtained, the design weak points of the lubricating oil pump are intuitively reflected, the lubricating oil pump is optimized and improved, and therefore damage caused by the design defects of the lubricating oil pump in the testing or working process is effectively avoided.

Description

Technical Field

[0001] The present invention belongs to the field of technical simulation, and relates to a fatigue life calculation method in the design process of an oil pump, specifically a method for simulating and calculating the designed oil pump by using finite element software with fatigue life analysis, simulating according to actual test or working conditions, and optimizing the design of the oil pump structure based on the calculation results. It relates to a fatigue life calculation method of an oil pump based on finite element software. Background Art

[0002] During the working process of the oil pump, when subjected to various alternating loads, fatigue cracks or failures will occur. Simulation analysis is an important part of the oil pump model design. It can timely detect weak links in the design at the initial stage of product design, thus providing data support for the optimization design of the structure, improving product reliability, and shortening the product development cycle. Therefore, it is necessary to simulate the oil pump, evaluate its fatigue life, and propose reasonable improvement plans.

[0003] Currently, the calculation methods specifically for the fatigue life of oil pumps in China mainly include theoretical formula calculation, testing, and simulation. The traditional fatigue life calculation method mainly conducts theoretical calculations through formulas. This method generally solves fatigue problems within the elastic range, without considering local elastoplastic deformation, resulting in relatively large calculation errors and a more cumbersome method. It is also possible to obtain the fatigue life of the oil pump through testing methods, but this can only be carried out after the product design is completed, cannot predict weak structural points in advance, and has high testing costs and a long cycle. Obtaining the fatigue life of parts through finite element simulation has been applied in engineering, but there is still a lack of a complete fatigue life analysis process at present, and steps such as simulation modeling, mesh generation, and load application are not standardized and comprehensive enough. Summary of the Invention

[0004] Object of the Invention

[0005] The problem to be solved by the present invention is to provide a fatigue life calculation method of an oil pump based on finite element software with fatigue life analysis, simulate the fatigue life of the newly designed oil pump by numerical simulation method, find out the weak points of the structural design, and provide a basis for the optimization design of the structure and the improvement of product reliability. To solve this technical problem,

[0006] Technical Solution

[0007] The technical solution provided by the present invention is as follows:

[0008] A fatigue life calculation method of an oil pump based on finite element software, comprising the following steps:

[0009] 1) Analyze the wear-out failure mechanism of the oil pump to determine the object of simulation analysis.

[0010] 2) Use 3D modeling software to establish a solid model of the lubricating oil pump, and simplify the model by removing unnecessary parts and geometric features that have no impact on the calculation results, and ensure that the model has no interference and no free state; the unnecessary parts include bolts, nuts, gaskets, and springs, and the geometric features include threads, small fillets, small chamfers, and text.

[0011] 3) Import the solid model in step 2) into a finite element software with fatigue life analysis, define the materials, contact pairs, mesh division, and boundary conditions of each component, and perform modal simulation calculations for the lubricating oil pump; the material parameters for the modal calculation of the lubricating oil pump include: density, elastic modulus, Poisson's ratio, S-N curve, yield limit, and fracture limit; the parts in mutual contact are set as bonded contacts; define the boundary conditions of the lubricating oil pump, and apply a 0 displacement constraint to the installation end face of the lubricating oil pump.

[0012] 4) According to the calculation results in step 3), perform harmonic response analysis using the modal superposition method, use a finite element software with fatigue life analysis, associate the harmonic response analysis system with the modal analysis system, and perform harmonic response simulation calculations; define the frequency sweep range and damping parameters according to the actual situation. When using the modal superposition method, use an aggregated model to capture the behavior near the natural frequency. Define the load condition as the gravitational acceleration load, and the direction is the actual working or test vibration direction. If the load is in multiple vibration directions, such as along the X, Y, and Z directions, then a harmonic response analysis needs to be re-established based on step 3), and the direction of the gravitational acceleration load is consistent with the vibration direction.

[0013] 5) For steps 2) and 3), use a finite element software with fatigue life analysis to perform vibration fatigue simulation calculations, associate the life vibration system with the modal analysis system, and then associate it with the harmonic response analysis system.

[0014] 6) Solve and display the fatigue life calculation results.

[0015] Furthermore, it further includes step 7), and step 7) calculates and checks the final life of the lubricating oil pump.

[0016] Furthermore, based on the structural decomposition and load analysis in step 1), considering all possible load types, analyze whether there are wear-out failure mechanisms in each part of the lubricating oil pump group during its life cycle, and determine the simulation analysis object of the lubricating oil pump.

[0017] Furthermore, for the modal calculation of the lubricating oil pump in step 3), it is necessary to define the names of each part of the lubricating oil pump to ensure that the life calculation results of each part can be obtained after fatigue life analysis.

[0018] Further, in step 3), perform modal calculation on the lubricating oil pump, check the modal calculation results. When the calculation results are unreasonable, return to steps 2) and 3) to check the calculation model, contact, and boundary conditions.

[0019] Further, in step 4), perform harmonic response calculation on the lubricating oil pump, and in step 5), perform vibration fatigue life calculation on the lubricating oil pump. Define the load spectrum, including random vibration load spectrum and harmonic response load spectrum, and the load spectrum is obtained from test data or actual working conditions.

[0020] Further, the results of the fatigue life calculation in step 6) include the frequencies and vibration modes of the overall lubricating oil pump and each component, response curves, damage, and life cloud maps.

[0021] Further, in step 7), calculate the final life of the lubricating oil pump and check. Manually calculate the vibration fatigue life / hour of each component of the lubricating oil pump according to the simulation damage results. According to the principle of the shortest time, obtain the final vibration fatigue life of the lubricating oil pump and check. The check standard requires that the life / hour of the lubricating oil pump is greater than the vibration time required by the test.

[0022] Further, if the load has multiple vibration directions, superimpose the damage results of each component of the lubricating oil pump in each direction to obtain the total damage of each component, and then calculate and check the vibration fatigue life of each component of the lubricating oil pump.

[0023] Further, the finite element software with fatigue life analysis is specifically Workbench software.

[0024] The beneficial effects of this application are as follows:

[0025] The beneficial effects of the present invention are: By calculating the fatigue life of the lubricating oil pump using the above process, a structural simulation model consistent with the actual design is established. Through modal analysis, harmonic response analysis, and fatigue life analysis, the natural frequencies, vibration modes, responses, damage, and life of the lubricating oil pump are obtained, which intuitively reflects the weak points in the design of the lubricating oil pump and optimizes and improves them, thus effectively avoiding damage caused by design defects of the lubricating oil pump during testing or operation.

[0026] This technical solution has been applied to the design and analysis of a large number of lubricating oil pumps and has been fully verified through tests. The technology is feasible, the results are reliable, and it effectively avoids damage caused by design defects of the lubricating oil pump during testing or operation. Specific embodiments

[0027] The present invention will be further described below in conjunction with embodiments. The following are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0028] An embodiment of the present invention provides a method for calculating the fatigue life of a lubricating oil pump based on finite element software with fatigue life analysis, and makes necessary optimization improvements to the structure of the lubricating oil pump according to the calculation results to improve the reliability of the lubricating oil pump. The method specifically includes:

[0029] 1) Mechanism analysis.

[0030] Conduct a wear-out failure mechanism analysis on the lubricating oil pump. Based on the structural decomposition and load analysis, consider all possible load types, analyze whether there is a wear-out failure mechanism for each part of the lubricating oil pump group during its life cycle, and determine the simulation analysis object of the lubricating oil pump;

[0031] 2) Use 3D modeling software to establish an assembly solid model of all simulation analysis objects of the lubricating oil pump according to step 1), and simplify the model, removing unnecessary parts and geometric features that have no impact on the calculation results, including threads, small fillets, small chamfers, and text features. The model has no interference and no free state;

[0032] 3) Import the solid model in step 2) into finite element software with fatigue life analysis, create a modal analysis process, define the materials, contact pairs, mesh division, and boundary conditions of each component, and perform modal simulation calculations on the lubricating oil pump. If the calculation results are unreasonable, check the calculation model, contact pairs, and boundary conditions, and re-analyze until the results are reasonable;

[0033] 4) According to the calculation results in step 3), perform a harmonic response analysis using the modal superposition method. Use finite element software with fatigue life analysis to associate the harmonic response analysis system with the modal analysis system and perform harmonic response simulation calculations. Define the sweep frequency range and damping parameters according to the actual situation. Define the load condition as the gravitational acceleration load, and the direction is the actual working or test vibration direction. If the load is in multiple vibration directions, such as along the X, Y, and Z directions, then a harmonic response analysis needs to be re-established based on step 3), and the direction of the gravitational acceleration load is consistent with the vibration direction.

[0034] 5) For steps 2) and 3), perform vibration fatigue simulation calculations using finite element software with fatigue life analysis; define the load spectrum, including the random vibration load spectrum and the harmonic response load spectrum, and the load spectrum is obtained from test data.

[0035] 6) Solve and display the fatigue life calculation results, including the frequency and vibration mode, response curve, damage, and life contour map of the entire lubricating oil pump and each component.

[0036] 7) Calculate the final life of the lubricating oil pump and check it. Manually calculate the vibration fatigue life / hour of each part of the lubricating oil pump according to the damage results of the simulation. According to the principle of the shortest time, obtain the final vibration fatigue life of the lubricating oil pump and check it. The check standard requires that the life / hour of the lubricating oil pump is greater than the vibration time required by the test. If the load is in multiple vibration directions, superimpose the damage results of each part of the lubricating oil pump in each direction to obtain the total damage of each part, and then calculate the vibration fatigue life of each part of the lubricating oil pump and check it.

[0037] Those skilled in the art of this technology can understand that unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here. The specific embodiments described above have further elaborated on the purpose, technical solution and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calculating the fatigue life of an oil pump based on finite element software, characterized in that, it includes the following steps: Step 1) Conduct a wear-out failure mechanism analysis on the oil pump to determine the simulation analysis object; Step 2) Use 3D modeling software to establish a solid model of the oil pump, and simplify the model by removing unnecessary parts and geometric features that have no impact on the calculation results, and ensure that the model has no interference and no free state; Unnecessary parts include bolts, nuts, gaskets, and springs, and geometric features include threads, small fillets, small chamfers, and text. Step 3) Import the solid model in Step 2 into finite element software with fatigue life analysis, define the materials, contact pairs, mesh division, and apply boundary conditions of each component, and perform modal simulation calculations on the oil pump; The material parameters for the oil pump modal calculation include: density, elastic modulus, Poisson's ratio, S-N curve, yield limit, and fracture limit; The parts in contact with each other are set as bonded contacts; Define the boundary conditions of the oil pump, and apply a 0 displacement constraint to the installation end face of the oil pump. Step 4) According to the calculation results in Step 3, perform a harmonic response analysis using the modal superposition method, use finite element software with fatigue life analysis, associate the harmonic response analysis system with the modal analysis system, and perform harmonic response simulation calculations; Define the sweep frequency range and damping parameters according to the actual situation; When using the modal superposition method, use an aggregated model to capture the behavior near the natural frequency; Define the load condition as the gravitational acceleration load, and the direction is the actual working or test vibration direction; If the load has multiple vibration directions, such as along the X, Y, and Z directions, then a harmonic response analysis needs to be re-established based on Step 3, and the direction of the gravitational acceleration load is consistent with the vibration direction. Step 5) For Steps 2) and 3), perform vibration fatigue simulation calculations using finite element software with fatigue life analysis, associate the life vibration system with the modal analysis system, and then associate it with the harmonic response analysis system. Step 6) Solve and display the fatigue life calculation results.

2. The method according to claim 1, characterized in that, it further includes Step 7), and in Step 7), calculate and check the final life of the oil pump.

3. The method according to claim 2, characterized in that, in Step 1), based on the structural decomposition and load analysis, consider all possible load types, analyze whether there is a wear-out failure mechanism for each part of the oil pump group during its life cycle, and determine the oil pump simulation analysis object.

4. The method according to claim 3, characterized in that, in Step 3) for the oil pump modal calculation, it is necessary to define the names of each part of the oil pump to ensure that the life calculation results of each part can be obtained after the fatigue life analysis.

5. The method according to claim 4, characterized in that, in Step 3) for the oil pump modal calculation, view the modal calculation results. When the calculation results are unreasonable, return to Steps 2) and 3) to check the calculation model, contacts, and boundary conditions.

6. The method according to claim 5, characterized in that, In step 4), the harmonic response calculation of the lubricating oil pump is performed, and in step 5), the vibration fatigue life calculation of the lubricating oil pump is carried out. A load spectrum is defined, including a random vibration load spectrum and a harmonic response load spectrum, and the load spectrum is obtained from test data or actual working conditions.

7. The method according to claim 6, characterized in that the results of the fatigue life calculation in step 6) include the frequencies and vibration modes, response curves, damages, and life nephograms of the overall lubricating oil pump and its individual components.

8. The method according to claim 7, characterized in that in step 7), the final life of the lubricating oil pump is calculated and verified. The vibration fatigue life / hour of each component of the lubricating oil pump is manually calculated based on the simulation damage results, and the final vibration fatigue life of the lubricating oil pump is obtained and verified according to the principle of the shortest time; The verification standard requires that the life / hour of the lubricating oil pump is greater than the vibration time required by the test.

9. The method according to claim 8, characterized in that if the loads are in multiple vibration directions, the damage results of each component of the lubricating oil pump in each direction are superimposed to obtain the total damage of each component, and then the vibration fatigue life of each component of the lubricating oil pump is calculated and verified.

10. The method according to claim 9, characterized in that the finite element software with fatigue life analysis is specifically Workbench software.