Low-cycle fatigue analysis method and device for engine cylinder block and computer equipment

Abstract

The embodiment of the invention provides a low-cycle fatigue analysis method and device for an engine cylinder block and computer equipment. The method comprises the following steps: performing temperature field calculation on an established grid model of an engine cylinder block to generate temperature field data; inputting the temperature field data, the obtained bolt pre-tightening force and the cylinder body material parameters into a finite element model for finite element analysis and calculation to generate a strain calculation result; inputting the strain calculation result, the temperature field data and the obtained stress life curve into a fatigue analysis model to generate a fatigue analysis result; when the strain calculation result and the fatigue analysis result meet set requirements, low-cycle fatigue analysis is completed, and the set requirements include that the strain calculation result is smaller than a first set threshold value and the number of cycles in the fatigue analysis result is larger than a second set threshold value. According to the technical scheme provided by the embodiment of the invention, the low-cycle fatigue life of the engine cylinder block can be accurately evaluated based on the finite element model and the fatigue analysis model.

Description

Technical Field

[0001] This invention relates to the field of computer technology, and in particular to a method, apparatus, and computer equipment for low-cycle fatigue analysis of engine cylinder blocks. Background Technology

[0002] With the development of the automotive industry, hybrid powertrain engines have become one of the most important power sources for new energy vehicles. In new energy vehicles, hybrid powertrain engines can both charge the battery and provide power output to drive the vehicle. As fuel consumption requirements become increasingly stringent, high thermal efficiency engines have gradually emerged. As the engine block serves as the engine base, it withstands repeated external forces and temperature field changes under high temperature, high pressure, and high load operating environments.

[0003] Simulation methods for engine cylinder blocks typically simulate stress changes during high-temperature, high-pressure operation. Evaluating the failure caused by the maximum and minimum stress cycles during engine operation is the primary basis for judging design feasibility. Fatigue analysis of engine cylinder blocks generally only considers fatigue damage during engine operation. During temperature changes, variations in cylinder block wall thickness lead to increased localized stress and subsequent failure, making it impossible to accurately assess the low-cycle fatigue life of the engine cylinder block. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method, apparatus and computer device for low-cycle fatigue analysis of engine cylinder blocks, for accurately evaluating the low-cycle fatigue life of engine cylinder blocks.

[0005] On one hand, embodiments of the present invention provide a low-cycle fatigue analysis method for an engine cylinder block, including: Temperature field calculations are performed on the established mesh model of the engine cylinder block to generate temperature field data; The temperature field data, the obtained bolt preload force, and the cylinder material parameters are input into the finite element model for finite element analysis and calculation to generate strain calculation results. The strain calculation results, the temperature field data, and the obtained stress-life curve are input into the fatigue analysis model to generate fatigue analysis results. When the strain calculation result and the fatigue analysis result meet the set requirements, the low-cycle fatigue analysis is completed. The set requirements include that the strain calculation result is less than a first set threshold and the number of cycles in the fatigue analysis result is greater than a second set threshold.

[0006] Optionally, before performing temperature field calculations on the established engine cylinder block mesh model to generate temperature field data, the following steps are included: Establish an engine block model; The engine block model is meshed to generate a mesh model; The obtained bolt parameters are used to calculate and generate the bolt preload.

[0007] Optionally, the step of generating a mesh model by meshing the engine block model includes: The cylinder block, cylinder head, cylinder head bolts, valve guides, valve seats, and cylinder head gaskets of the engine cylinder block model are meshed using a second-order 3D mesh to generate a mesh model.

[0008] Optionally, the bolt parameters include: bolt preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch. The bolt preload coefficient includes a maximum preload coefficient, a minimum preload coefficient, and a preload coefficient after attenuation. The step of calculating the bolt preload from the acquired bolt parameters includes: The maximum bolt preload is generated based on the maximum preload coefficient, the bolt yield strength, the bolt nominal diameter, and the bolt pitch. The minimum bolt preload is generated based on the minimum preload coefficient, the bolt yield strength, the bolt nominal diameter, and the bolt pitch. The attenuated bolt preload is generated based on the attenuated preload coefficient, the bolt yield strength, the bolt nominal diameter, and the bolt pitch.

[0009] Optionally, the step of inputting the strain calculation results, the temperature field data, and the acquired stress-life curve into the fatigue analysis model to generate fatigue analysis results includes: Input the strain calculation results, the temperature field data, and the obtained stress-life curve into the fatigue analysis model, and select the set working conditions to generate fatigue analysis results; The set operating conditions include a first set operating condition, a second set operating condition, and a third set operating condition; The first set operating conditions include: minimum bolt preload, interference fit between valve guide and cylinder head, and interference fit between valve seat and cylinder head; The second set operating conditions include: maximum bolt preload, interference fit between valve guide and cylinder head, interference fit between valve seat and cylinder head, and rated operating temperature field; The third set operating conditions include: the preload of the weakened bolts, the interference fit between the valve guide and the cylinder head, the interference fit between the valve seat and the cylinder head, and the ambient temperature field.

[0010] Optionally, the step of performing temperature field calculations on the established mesh model of the engine cylinder block to generate temperature field data includes: Based on the mesh model, temperature field data is generated by calculating the thermal boundary, heat transfer coefficient, and thermal conductivity using a fluid-structure interaction method.

[0011] Optionally, it also includes: When the strain calculation results and fatigue analysis results do not meet the set requirements, the part of the engine block that does not meet the set requirements will be structurally adjusted, and the step of establishing the engine block model will continue.

[0012] On the other hand, embodiments of the present invention provide a low-cycle fatigue analysis device for an engine cylinder block, comprising: The first generation module is used to calculate the temperature field of the established engine cylinder block mesh model and generate temperature field data. The second generation module is used to input the temperature field data, the acquired bolt preload force and cylinder material parameters into the finite element model to perform finite element analysis and calculation to generate strain calculation results; The third generation module is used to input the strain calculation results, the temperature field data and the acquired stress-life curve into the fatigue analysis model and select the set working conditions to generate fatigue analysis results. The analysis module is used to complete low-cycle fatigue analysis when the strain calculation results and the fatigue analysis results meet the set requirements.

[0013] On the other hand, embodiments of the present invention provide a storage medium including a stored program, wherein, when the program is executed, the device where the storage medium is located is controlled to perform the aforementioned low-cycle fatigue analysis method for engine cylinder blocks.

[0014] On the other hand, embodiments of the present invention provide a computer device including a memory and a processor. The memory is used to store information including program instructions, and the processor is used to control the execution of the program instructions. When the program instructions are loaded and executed by the processor, the steps of the low-cycle fatigue analysis method for the engine cylinder block described above are implemented.

[0015] In the technical solution provided by this invention, temperature field calculations are performed on the established mesh model of the engine cylinder block to generate temperature field data. The temperature field data, the acquired bolt preload, and cylinder block material parameters are input into a finite element model for finite element analysis to generate strain calculation results. The strain calculation results, temperature field data, and the acquired stress-life curve are input into a fatigue analysis model to generate fatigue analysis results. When the strain calculation results and fatigue analysis results meet set requirements, low-cycle fatigue analysis is completed. These set requirements include that the strain calculation result is less than a first set threshold and the number of cycles in the fatigue analysis results is greater than a second set threshold. The technical solution provided by this invention can accurately evaluate the low-cycle fatigue life of the engine cylinder block based on the finite element model and the fatigue analysis model. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A flowchart of a low-cycle fatigue analysis method for an engine cylinder block provided in an embodiment of the present invention; Figure 2 A flowchart of another low-cycle fatigue analysis method for an engine cylinder block provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of temperature field data under rated operating conditions provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a finite element model provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a strain calculation result provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of a fatigue analysis result provided in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating a structural adjustment of a portion of an engine block that does not meet set requirements, according to an embodiment of the present invention. Figure 8 This is a schematic diagram of a low-cycle fatigue analysis device for an engine cylinder block provided in an embodiment of the present invention; Figure 9 A schematic diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0018] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0019] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0022] An embodiment of the present invention provides a low-cycle fatigue analysis method for an engine cylinder block. Figure 1 A flowchart of a low-cycle fatigue analysis method for an engine cylinder block provided in an embodiment of the present invention is shown below. Figure 1 As shown, the method includes: Step 102: Perform temperature field calculations on the established engine cylinder block mesh model to generate temperature field data.

[0023] In this embodiment of the invention, the temperature field data of the engine block under rated operating conditions can be generated by calculating the thermal boundary, heat transfer coefficient and thermal conductivity based on the mesh model using the fluid-structure interaction method.

[0024] Step 104: Input the temperature field data, the obtained bolt preload and cylinder material parameters into the finite element model to perform finite element analysis and generate strain calculation results.

[0025] In this embodiment of the invention, the pre-collected cylinder block material parameters include: cylinder head gasket pressure change curve, density, elastic modulus, Poisson's ratio and stress-strain of cylinder block and cylinder head material as a function of temperature, interference between valve guide and cylinder head, and interference between valve seat and cylinder head.

[0026] In this embodiment of the invention, a finite element model can be built using Abaqus.

[0027] Step 106: Input the strain calculation results, temperature field data, and obtained stress-life curve into the fatigue analysis model to generate fatigue analysis results.

[0028] In this embodiment of the invention, strain calculation results, temperature field data, and acquired stress-life curves can be input into the fatigue analysis model femfat, and the set working conditions can be selected to generate fatigue analysis results.

[0029] Step 108: When the strain calculation results and fatigue analysis results meet the set requirements, complete the low-cycle fatigue analysis. The set requirements include that the strain calculation results are less than the first set threshold and the number of cycles in the fatigue analysis results is greater than the second set threshold.

[0030] In this embodiment of the invention, a first set threshold and a second set threshold can be set according to actual conditions. For example, the first set threshold is 0.01 mm, and the second set threshold is 1,000,000 mm.

[0031] In the technical solution provided by this invention, temperature field calculations are performed on the established mesh model of the engine cylinder block to generate temperature field data. The temperature field data, the acquired bolt preload, and cylinder block material parameters are input into a finite element model for finite element analysis to generate strain calculation results. The strain calculation results, temperature field data, and the acquired stress-life curve are input into a fatigue analysis model to generate fatigue analysis results. When the strain calculation results and fatigue analysis results meet set requirements, low-cycle fatigue analysis is completed. These set requirements include that the strain calculation result is less than a first set threshold and the number of cycles in the fatigue analysis results is greater than a second set threshold. The technical solution provided by this invention can accurately evaluate the low-cycle fatigue life of the engine cylinder block based on the finite element model and the fatigue analysis model.

[0032] Another method for low-cycle fatigue analysis of engine cylinder blocks is provided in one embodiment of the present invention. Figure 2 A flowchart of another low-cycle fatigue analysis method for an engine cylinder block provided in an embodiment of the present invention is shown below. Figure 2 As shown, the method includes: Step 202: Establish the engine block model.

[0033] Step 204: Mesh the engine block model to generate a mesh model.

[0034] Specifically, the cylinder block, cylinder head, cylinder head bolts, valve guides, valve seats, and cylinder head gaskets of the engine cylinder block model can be meshed using a second-order 3D mesh to generate a mesh model.

[0035] Step 206: Calculate the obtained bolt parameters to generate bolt preload.

[0036] In this embodiment of the invention, bolt parameters can be obtained, including: bolt preload coefficient, bolt yield strength, bolt nominal diameter and bolt pitch. The bolt preload coefficient includes the maximum preload coefficient, the minimum preload coefficient and the preload coefficient after attenuation.

[0037] In this embodiment of the invention, the maximum bolt preload can be generated based on the maximum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch. Specifically, this is achieved using formula F. bolt1 =K1 σ pr (π / 4)(D) bolt -0.9382 P bolt ) 2 The maximum preload is calculated based on the maximum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch to generate the maximum bolt preload. Wherein, F... bolt1K1 is the maximum bolt preload, and σ is the maximum preload coefficient. pr D is the bolt yield strength. bolt P is the nominal diameter of the bolt. bolt This refers to the bolt pitch.

[0038] In this embodiment of the invention, the minimum bolt preload can be generated based on the minimum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch. Specifically, this is achieved using formula F. bolt2 =K2 σ pr (π / 4)(D) bolt -0.9382 P bolt ) 2 The minimum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch are calculated to generate the minimum bolt preload. Wherein, F bolt2 K2 is the minimum bolt preload, and σ is the minimum preload coefficient. pr D is the bolt yield strength. bolt P is the nominal diameter of the bolt. bolt This refers to the bolt pitch.

[0039] In this embodiment of the invention, the attenuated bolt preload can be generated based on the attenuated preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch. Specifically, it is achieved through formula F. bolt3 =K3 σ pr (π / 4)(D) bolt -0.9382 P bolt ) 2 The attenuated preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch are calculated to generate the attenuated bolt preload. Wherein, F bolt3 K3 is the preload force after attenuation, and σ is the preload force coefficient after attenuation. pr D is the bolt yield strength. bolt P is the nominal diameter of the bolt. bolt This refers to the bolt pitch.

[0040] Step 208: Perform temperature field calculations on the established engine cylinder block mesh model to generate temperature field data.

[0041] In this embodiment of the invention, the temperature field data of the engine block under rated operating conditions can be generated by calculating the thermal boundary, heat transfer coefficient and thermal conductivity based on the mesh model using the fluid-structure interaction method. Figure 3 This is a schematic diagram of temperature field data under rated operating conditions provided in an embodiment of the present invention, as shown below. Figure 3As shown, the combustion chamber temperature inside the cylinder is higher, while the cylinder wall temperature outside the cylinder is lower.

[0042] Step 210: Input the temperature field data, the obtained bolt preload and cylinder material parameters into the finite element model to perform finite element analysis and generate strain calculation results.

[0043] In this embodiment of the invention, the pre-designed cylinder block material parameters include: cylinder head gasket pressure change curve, cylinder block and cylinder head material density, elastic modulus, Poisson's ratio and stress strain as a function of temperature, interference between valve guide and cylinder head, and interference between valve seat and cylinder head.

[0044] In this embodiment of the invention, when inputting cylinder block material parameters, the cylinder block material parameters can be material parameters at different temperatures (including stress-strain curves), and the cylinder head gasket input force curve with deformation (including opening and compression processes).

[0045] In this embodiment of the invention, the strain calculation result (stress value) of the engine cylinder block during the working process can be accurately calculated based on the cylinder block material parameters.

[0046] In this embodiment of the invention, a finite element model can be built using Abaqus. Figure 4 This is a schematic diagram of a finite element model provided in an embodiment of the present invention, as shown below. Figure 4 As shown, Figure 4 (A) is a schematic diagram of the vertical (Z-axis) constraint of the finite element model, (B) is a schematic diagram of the horizontal (Y-axis) constraint of the finite element model, and (C) is a schematic diagram of the axial (X-axis) constraint of the finite element model.

[0047] Figure 5 This is a schematic diagram of a strain calculation result provided in an embodiment of the present invention, as shown below. Figure 5 As shown, Figure 5 The strain calculation results for the engine cylinder block can include the stress and strain values ​​of the engine cylinder block.

[0048] Step 212: Input the strain calculation results, temperature field data, and obtained stress-life curve into the fatigue analysis model to generate fatigue analysis results.

[0049] In this embodiment of the invention, stress life curves can be pre-stored.

[0050] In this embodiment of the invention, strain calculation results, temperature field data, and acquired stress-life curves can be input into the fatigue analysis model femfat, and a set working condition (either a second or a third set working condition) can be selected to generate fatigue analysis results. The set working conditions include a first set working condition, a second set working condition, and a third set working condition.

[0051] For example, the first set operating condition includes: minimum bolt preload, interference fit between valve guide and cylinder head, and interference fit between valve seat and cylinder head. The second set operating condition includes: maximum bolt preload, interference fit between valve guide and cylinder head, interference fit between valve seat and cylinder head, and rated operating temperature field. The third set operating condition includes: reduced bolt preload, interference fit between valve guide and cylinder head, interference fit between valve seat and cylinder head, and ambient temperature field (20℃).

[0052] In this embodiment of the invention, the influence of temperature on the fatigue analysis results can be selected in the fatigue analysis model femfat. For example, the temperature field can be the temperature field data at the rated speed, and the cylinder material parameters need to change with the temperature field.

[0053] In this embodiment of the invention, the fatigue analysis results may disregard the influence of roughness.

[0054] In this embodiment of the invention, the stress-life curve is input into the fatigue analysis model femfat, which can take into account the influence of temperature on the fatigue analysis results.

[0055] Figure 6 This is a schematic diagram of a fatigue analysis result provided in an embodiment of the present invention, as shown below. Figure 6 As shown, Figure 6 The fatigue analysis results are used to characterize the number of cycles in various parts of the engine block.

[0056] Step 214: Determine whether the strain calculation results and fatigue analysis results meet the set requirements. If yes, proceed to step 216; otherwise, proceed to step 218.

[0057] In this embodiment of the invention, the set requirements include the strain calculation result being less than a first set threshold and the number of cycles in the fatigue analysis result being greater than a second set threshold.

[0058] In this embodiment of the invention, a first set threshold and a second set threshold can be set according to actual conditions. For example, the first set threshold is 0.01 mm, and the second set threshold is 1,000,000 mm.

[0059] Step 216: Complete the low-cycle fatigue analysis; the process ends.

[0060] Step 218: Adjust the structure of the parts of the engine block that do not meet the set requirements, and proceed to step 202.

[0061] Figure 7 This is a schematic diagram illustrating a structural adjustment of a portion of an engine block that does not meet set requirements, as provided in an embodiment of the present invention. Figure 7As shown, the fatigue analysis results for the rounded corner portion of the engine block have a cycle count of 235,000, which is less than the second set threshold of 1,000,000. Therefore, structural adjustments to the rounded corner portion of the engine block are necessary. For example, the structural adjustments to the rounded corner portion of the engine block can be made by reducing the cylinder block wall thickness and increasing the rounded corner radius.

[0062] In the technical solution provided by this invention, temperature field calculations are performed on the established mesh model of the engine cylinder block to generate temperature field data. The temperature field data, the acquired bolt preload, and cylinder block material parameters are input into a finite element model for finite element analysis to generate strain calculation results. The strain calculation results, temperature field data, and the acquired stress-life curve are input into a fatigue analysis model to generate fatigue analysis results. When the strain calculation results and fatigue analysis results meet set requirements, low-cycle fatigue analysis is completed. These set requirements include that the strain calculation result is less than a first set threshold and the number of cycles in the fatigue analysis results is greater than a second set threshold. The technical solution provided by this invention can accurately evaluate the low-cycle fatigue life of the engine cylinder block based on the finite element model and the fatigue analysis model.

[0063] The technical solution provided in this invention provides a low-cycle fatigue analysis method for engine cylinder blocks that features fast modeling speed, high efficiency, and high calculation accuracy.

[0064] The technical solution provided in this invention uses a finite element model and a fatigue analysis model for simulation, which enables rapid and effective low-cycle fatigue analysis.

[0065] The technical solution provided in this invention uses a steady-state calculation method, which can quickly and accurately assess the low-cycle fatigue life of the engine cylinder block.

[0066] The technical solution provided in this invention embodiment can better evaluate the damage value caused by alternating temperature field changes compared with high-cycle fatigue simulation, making the evaluation of the low-cycle fatigue life of engine cylinder block more accurate.

[0067] The technical solutions provided in the embodiments of the present invention are characterized by rapid analysis and solution, fast response, and short iterative adjustment cycle.

[0068] One embodiment of the present invention provides a low-cycle fatigue analysis device for engine cylinder blocks. Figure 8 This is a schematic diagram of a low-cycle fatigue analysis device for an engine cylinder block provided in an embodiment of the present invention, as shown below. Figure 8 As shown, the device includes: a first generation module 11, a second generation module 12, a third generation module 13, and an analysis module 14.

[0069] The first generation module 11 is used to perform temperature field calculations on the established mesh model of the engine cylinder block and generate temperature field data.

[0070] The second generation module 12 is used to input temperature field data, acquired bolt preload and cylinder material parameters into the finite element model to perform finite element analysis and generate strain calculation results.

[0071] The third generation module 13 is used to input the strain calculation results, temperature field data and the acquired stress-life curve into the fatigue analysis model and select the set working conditions to generate fatigue analysis results.

[0072] Analysis module 14 is used to complete low-cycle fatigue analysis when the strain calculation results and fatigue analysis results meet the set requirements.

[0073] In this embodiment of the invention, the device further includes: a creation module 15, a fourth generation module 16, and a fifth generation module 17.

[0074] Module 15 is used to create the engine block model.

[0075] The fourth generation module 16 is used to generate a mesh model by meshing the engine block model.

[0076] The fifth generation module 17 is used to calculate the bolt preload based on the acquired bolt parameters.

[0077] In this embodiment of the invention, the fourth generation module 16 is specifically used to perform mesh division on the cylinder block, cylinder head, cylinder head bolts, valve guides, valve seats, and cylinder head gaskets of the engine cylinder block model using a second-order 3D mesh, and generate a mesh model.

[0078] In this embodiment of the invention, the bolt parameters include: bolt preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch. The bolt preload coefficient includes a maximum preload coefficient, a minimum preload coefficient, and a preload coefficient after attenuation. The fifth generation module 17 is specifically used to generate the maximum bolt preload based on the maximum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch; generate the minimum bolt preload based on the minimum preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch; and generate the preload coefficient after attenuation based on the preload coefficient, bolt yield strength, bolt nominal diameter, and bolt pitch.

[0079] In this embodiment of the invention, the third generation module 13 is specifically used to input the strain calculation results, the temperature field data, and the acquired stress-life curve into the fatigue analysis model, and select a set working condition to generate fatigue analysis results; wherein, the set working condition includes a first set working condition, a second set working condition, and a third set working condition; the first set working condition includes: minimum bolt preload, interference fit between valve guide and cylinder head, and interference fit between valve seat and cylinder head; the second set working condition includes: maximum bolt preload, interference fit between valve guide and cylinder head, interference fit between valve seat and cylinder head, and rated working condition temperature field; the third set working condition includes: attenuated bolt preload, interference fit between valve guide and cylinder head, interference fit between valve seat and cylinder head, and room temperature temperature field.

[0080] In this embodiment of the invention, the first generation module 11 is specifically used to calculate and generate temperature field data based on the thermal boundary, heat transfer coefficient and thermal conductivity using a fluid-structure interaction method based on a mesh model.

[0081] In this embodiment of the invention, the analysis module 14 is further configured to adjust the structure of the part of the engine block that does not meet the set requirements when the strain calculation results and fatigue analysis results do not meet the set requirements, and trigger the establishment module 15 to continue to execute the step of establishing the engine block model.

[0082] In the technical solution provided by this invention, temperature field calculations are performed on the established mesh model of the engine cylinder block to generate temperature field data. The temperature field data, the acquired bolt preload, and cylinder block material parameters are input into a finite element model for finite element analysis to generate strain calculation results. The strain calculation results, temperature field data, and the acquired stress-life curve are input into a fatigue analysis model to generate fatigue analysis results. When the strain calculation results and fatigue analysis results meet set requirements, low-cycle fatigue analysis is completed. These set requirements include that the strain calculation result is less than a first set threshold and the number of cycles in the fatigue analysis results is greater than a second set threshold. The technical solution provided by this invention can accurately evaluate the low-cycle fatigue life of the engine cylinder block based on the finite element model and the fatigue analysis model.

[0083] The low-cycle fatigue analysis device for engine cylinder blocks provided in this embodiment of the invention can be used to achieve the above. Figure 1 or Figure 2 The method for low-cycle fatigue analysis of engine cylinder blocks is described in detail in the embodiments of the method for low-cycle fatigue analysis of engine cylinder blocks described above, and will not be repeated here.

[0084] This invention provides a storage medium that includes a stored program. When the program runs, it controls the device where the storage medium is located to execute the steps of the embodiments of the low-cycle fatigue analysis method for engine cylinder blocks described above. For a detailed description, please refer to the embodiments of the low-cycle fatigue analysis method for engine cylinder blocks described above.

[0085] This invention provides a computer device including a memory and a processor. The memory stores information including program instructions, and the processor controls the execution of the program instructions. When the program instructions are loaded and executed by the processor, they implement the steps of the embodiment of the low-cycle fatigue analysis method for engine cylinder blocks described above. For a detailed description, please refer to the embodiment of the low-cycle fatigue analysis method for engine cylinder blocks described above.

[0086] Figure 9 A schematic diagram of a computer device provided in an embodiment of the present invention. (See diagram below.) Figure 9 As shown, the computer device 20 in this embodiment includes a processor 21, a memory 22, and a computer program 23 stored in the memory 22 and executable on the processor 21. When the processor 21 executes the computer program 23, it implements the low-cycle fatigue analysis method applied to the engine cylinder block in this embodiment. To avoid repetition, it will not be described in detail here. Alternatively, when the processor 21 executes the computer program, it implements the functions of each model / unit in the low-cycle fatigue analysis device applied to the engine cylinder block in this embodiment. To avoid repetition, it will not be described in detail here.

[0087] Computer device 20 includes, but is not limited to, processor 21 and memory 22. Those skilled in the art will understand that... Figure 9 This is merely an example of computer device 20 and does not constitute a limitation on computer device 20. It may include more or fewer components than shown, or combine certain components, or different components. For example, computer device may also include input / output devices, network access devices, buses, etc.

[0088] The processor 21 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0089] The memory 22 can be an internal storage unit of the computer device 20, such as a hard disk or RAM of the computer device 20. The memory 22 can also be an external storage device of the computer device 20, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the computer device 20. Furthermore, the memory 22 can include both internal and external storage units of the computer device 20. The memory 22 is used to store computer programs and other programs and data required by the computer device. The memory 22 can also be used to temporarily store data that has been output or will be output.

[0090] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0091] In the embodiments provided by this invention, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units through some interfaces, and may be electrical, mechanical, or other forms.

[0092] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0093] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0094] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low cycle fatigue analysis method of an engine block, characterized by, The method comprises the following steps: temperature field calculation is performed on the established grid model of the engine cylinder block to generate temperature field data; the temperature field data, the obtained bolt pre-tightening force and the cylinder block material parameters are input into the finite element model to perform finite element analysis calculation to generate strain calculation results; the strain calculation results, the temperature field data and the obtained stress-life curve are input into a fatigue analysis model to generate fatigue analysis results; when the strain calculation results and the fatigue analysis results meet the set requirements, the low-cycle fatigue analysis is completed, wherein the set requirements include that the strain calculation results are less than a first set threshold and the cycle number in the fatigue analysis results is greater than a second set threshold.

2. The method of claim 1, wherein, Before the temperature field calculation is performed on the established grid model of the engine cylinder block to generate temperature field data, the method comprises the following steps: establishing an engine cylinder block model; grid division is performed on the engine cylinder block model to generate a grid model; bolt parameters are calculated to generate a bolt pre-tightening force.

3. The method of claim 2, wherein, The grid division is performed on the engine cylinder block model to generate a grid model, which comprises the following steps: second-order 3D grid is used for grid division on the cylinder block, the cylinder head, the cylinder head bolt, the valve guide, the valve seat ring and the cylinder head gasket of the engine cylinder block model to generate a grid model.

4. The method of claim 2, wherein, The bolt parameters include a bolt pre-tightening force coefficient, a bolt yield strength, a bolt nominal diameter and a bolt pitch, the bolt pre-tightening force coefficient includes a maximum pre-tightening force coefficient, a minimum pre-tightening force coefficient and a post-attenuation pre-tightening force coefficient, and the calculation of the obtained bolt parameters to generate a bolt pre-tightening force comprises the following steps: generating a maximum bolt pre-tightening force according to the maximum pre-tightening force coefficient, the bolt yield strength, the bolt nominal diameter and the bolt pitch; generating a minimum bolt pre-tightening force according to the minimum pre-tightening force coefficient, the bolt yield strength, the bolt nominal diameter and the bolt pitch; generating a post-attenuation bolt pre-tightening force according to the post-attenuation pre-tightening force coefficient, the bolt yield strength, the bolt nominal diameter and the bolt pitch.

5. The method of claim 4, wherein, The input of the strain calculation results, the temperature field data and the obtained stress-life curve into the fatigue analysis model to generate fatigue analysis results comprises the following steps: the strain calculation results, the temperature field data and the obtained stress-life curve are input into the fatigue analysis model, and a set working condition is selected to generate fatigue analysis results; wherein the set working condition includes a first set working condition, a second set working condition and a third set working condition; the first set working condition includes a minimum bolt pre-tightening force, an interference fit between the valve guide and the cylinder head and an interference fit between the valve seat ring and the cylinder head; the second set working condition includes a maximum bolt pre-tightening force, an interference fit between the valve guide and the cylinder head, an interference fit between the valve seat ring and the cylinder head and a rated working condition temperature field; the third set working condition includes a post-attenuation bolt pre-tightening force, an interference fit between the valve guide and the cylinder head, an interference fit between the valve seat ring and the cylinder head and a normal temperature temperature field.

6. The method of claim 1, wherein, The temperature field calculation performed on the established grid model of the engine cylinder block to generate temperature field data comprises the following steps: temperature field data is generated by calculating the thermal boundary, the heat exchange coefficient and the thermal conductivity coefficient based on the grid model through a fluid-structure coupling method.

7. The method of claim 1, wherein, The method further comprises the following steps: When the strain calculation result and the fatigue analysis result do not meet the set requirement, the part of the engine cylinder body that does not meet the set requirement is adjusted in structure, and the step of establishing the engine cylinder body model is continuously executed.

8. An apparatus for low cycle fatigue analysis of an engine block, characterized by, The method comprises the steps of: a first generation module is configured to perform temperature field calculation on the established grid model of the engine cylinder body to generate temperature field data; a second generation module is configured to input the temperature field data, the obtained bolt pre-tightening force and the cylinder body material parameters into a finite element model to perform finite element analysis calculation to generate a strain calculation result; a third generation module is configured to input the strain calculation result, the temperature field data and the obtained stress-life curve into a fatigue analysis model and select a set working condition to generate a fatigue analysis result; an analysis module is configured to complete low-cycle fatigue analysis when the strain calculation result and the fatigue analysis result meet the set requirement.

9. A storage medium, characterized by The storage medium comprises a stored program, wherein the program controls the device in which the storage medium is located to execute the low-cycle fatigue analysis method of the engine cylinder body according to any one of claims 1 to 7 when the program is running.

10. A computer device comprising a memory for storing information including program instructions, and a processor for controlling execution of the program instructions, characterized in that, The program instructions are loaded and executed by the processor to implement the steps of the low-cycle fatigue analysis method of the engine cylinder body according to any one of claims 1 to 7.

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