Design method of cylinder cover characteristic position heat engine coupling equivalent simulation part

Abstract

The invention provides a design method of a cylinder cover characteristic position heat engine coupling equivalent simulation part, and relates to the technical field of cylinder cover simulation part preparation. Comprising the following steps: determining structural characteristics of a to-be-simulated cylinder cover and obtaining stress-strain distribution of the to-be-simulated cylinder cover under heat engine coupling; according to the structural features, simplifying the model of the cylinder cover to be simulated by adopting a region suppression method to obtain a final simplified model; establishing a corresponding initial equivalent simulation part model according to the structural size parameters of the structural features and the final simplified model; the stress-strain mean value of the initial equivalent simulation part model is optimized through the stress-strain mean value of the final simplified model, and optimal key structure parameters of the initial equivalent simulation part model are obtained; and designing a final equivalent simulation part model according to the optimal key structure parameters. The problems that in the prior art, a test piece model is too complex, and a cooling water channel structure is not sufficiently considered are solved.

Description

Technical Field

[0001] The invention relates to the technical field of cylinder head simulation part preparation, and in particular to a design method for a thermo-mechanical coupling equivalent simulation part at a characteristic position of a cylinder head. Background Art

[0002] The cylinder head is one of the important structural components of the internal combustion engine. It is used to close the upper part of the cylinder and form a combustion chamber together with the top of the piston and the cylinder wall. The cylinder head has an extremely complex structure, on which are processed the intake and exhaust valves, valve guide holes, etc., and the cooling water channel, intake and exhaust pipes and part of the combustion chamber are cast inside. When the internal combustion engine is working, the working environment of the cylinder head is very harsh and the stress conditions are very complicated. It not only needs to bear the mechanical loads such as the bolt preload generated during the assembly process of the internal combustion engine, but also needs to bear the heat load generated by gas combustion and the gas explosion pressure load. At the same time, due to the existence of cooling water channels, factors such as the uneven distribution of the coolant flow path will also lead to complex distribution of temperature and stress fields inside the cylinder head.

[0003] During service, cylinder heads face complex coupling effects of multiple physical fields, including thermal, fluid, and solid coupling. However, traditional testing methods have some inherent limitations in dealing with these challenges, including high economic costs, lengthy test cycles, complex operating procedures, and limitations in accuracy and precision.

[0004] The prior art closest to the present invention is "A Cylinder Head Simulation Part Fatigue Test Method" [2015-07-22] disclosed in CN104792632A. This method uses a pure mechanical fatigue test instead of a thermal-mechanical coupling fatigue test, which reduces the test cycle and ensures the accuracy of the test to a certain extent. The specific steps are as follows: calculate the three principal stress-strain values ​​of different dangerous positions of the solid cylinder head by the finite element simulation method; establish a test piece model; set the maximum cyclic load value required to be applied on the unidirectional tension and compression test bench; calculate the three principal stress-strain values ​​of the dangerous position of the test piece model; compare the three principal stress-strain values ​​of the dangerous position of the test piece model with those of the solid cylinder head to determine the final test piece model; process the final test piece model and then perform a fatigue test on the unidirectional tension and compression test bench. The structure of the test piece model is firstly determined based on the appearance characteristics of the cylinder head fire surface. Furthermore, since the traditional fatigue test bench cannot mount a solid cylinder head with a large volume and complex structure, and the fatigue test bench is difficult to achieve high-precision measurement of the dangerous position - the cylinder head fire surface, this invention designs a test piece that is easy to mount and measure and can reflect the stress-strain characteristics of the dangerous position, that is, the cylinder head test piece model.

[0005] However, the test piece model has a significant flaw, which is that it fails to fully incorporate the geometric configuration of the cooling channels. The design of the cooling channels is crucial to regulating the temperature distribution of the cylinder head, reducing thermal stress concentration, and improving structural integrity. In actual work, the shape and layout of the cooling channels directly affect the temperature field and thermal stress state of the cylinder head, which in turn affects its fatigue life. Therefore, the test piece model lacking the cooling channel structure may not be able to fully simulate the thermal-mechanical coupling behavior of the actual cylinder head under working conditions, which may have a negative impact on the accuracy and reliability of the test results.

[0006] Another prior art that is relatively similar to the present invention is "A method for predicting the thermal-fluid-solid coupling fatigue life of a diesel engine cylinder head considering machining residual stress" [2024-07-16] disclosed in CN118350318A. This patent proposes a method for predicting the thermal-fluid-solid coupling fatigue life of a diesel engine cylinder head considering machining residual stress. It comprehensively considers the influence of machining residual stress on the fatigue life of the cylinder head, and considers the uneven hot and cold of the structure caused by the high-temperature gas and coolant in the cylinder head when calculating the temperature field, as well as the thermal engine fatigue life of the cylinder head under multiple working conditions such as high pressure and high temperature. The specific steps are as follows: construct the final simplified model of the diesel engine cylinder head; preset the life and death unit layer, use the life and death unit technology to perform multi-process cutting simulation analysis on the diesel engine cylinder head, and obtain the cutting residual stress of the cylinder head; use flow field analysis to obtain the surface temperature parameters of the cylinder head; calculate the temperature field distribution of the cylinder head according to the surface temperature parameters; perform stress field analysis based on the residual stress obtained after the cylinder head cutting and the temperature field of the cylinder head, and apply mechanical loads and thermal stress loads to calculate the mechanical stress and thermal stress of the cylinder head; predict the thermal engine fatigue life of the diesel engine cylinder head according to the cylinder head temperature field, cylinder head thermal stress, mechanical stress and material properties, and obtain the fatigue life cloud map of the diesel engine cylinder head.

[0007] The patent builds the final simplified model of the cylinder head, which removes small features that do not affect the calculation results in each part, and simplifies the cylinder head base into a rectangular block. The model takes into account a variety of structural features, such as cooling channels, valve holes, and bolt holes, but this highly detailed model also increases the calculation complexity, time and cost. Summary of the invention

[0008] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a design method for a thermal-mechanical coupling equivalent simulation part at a characteristic position of a cylinder head, which solves the problems in the prior art of overly complex test piece models and insufficient consideration of cooling water channel structures.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] A design method for a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head, comprising:

[0011] Determining the structural characteristics of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling;

[0012] According to the structural features, a regional suppression method is used to simplify the model of the cylinder head to be simulated to obtain a final simplified model;

[0013] Determining the stress and strain mean value of the final simplified model according to the stress and strain distribution of the cylinder head to be simulated under the thermal-mechanical coupling;

[0014] Establishing a corresponding initial equivalent simulation component model according to the structural dimension parameters of the structural features and the final simplified model;

[0015] Determining the stress and strain distribution of the initial equivalent simulation component model to obtain the stress and strain mean of the initial equivalent simulation component model;

[0016] Optimizing the stress-strain mean of the initial equivalent simulation model using the stress-strain mean of the final simplified model to obtain the optimal key structural parameters of the initial equivalent simulation model, wherein the key structural parameters include: width parameter, height parameter and thickness parameter;

[0017] The final equivalent simulation component model is designed according to the optimal key structural parameters.

[0018] Preferably, the step of determining the structural features of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling includes:

[0019] determining a nose bridge region as a structural feature of the simulated cylinder head;

[0020] Performing finite element network division on the cylinder head to be simulated, wherein the structural feature area is divided by a high-density network;

[0021] Apply appropriate thermal boundary conditions to each area of ​​the cylinder head to be simulated after dividing the network units to obtain the temperature field distribution of the cylinder head;

[0022] The thermal stress field is obtained according to the temperature field distribution

[0023] The maximum alternating working load and assembly load are superimposed to obtain the coupled stress field;

[0024] The stress-strain distribution is determined according to the thermal stress field and the coupled stress field.

[0025] Preferably, according to the structural features, the model of the cylinder head to be simulated is simplified by adopting a regional suppression method to obtain a final simplified model, including:

[0026] Simplifying the intake and exhaust valves of the cylinder head model to obtain a first simplified model;

[0027] Simplifying the bolt holes, pin holes and ribs of the first simplified model to obtain a second simplified model;

[0028] The concave platforms and convex platforms of the second simplified model are simplified to obtain a final simplified model.

[0029] Preferably, the cross-section of the equivalent simulation part model is a T-shaped cross-section.

[0030] Preferably, the method for obtaining the optimal key structural parameters is:

[0031] determining a first set of key structural parameters according to the stress function;

[0032] determining a second set of key structural parameters according to the strain function;

[0033] The minimum values ​​of the parameters corresponding to the first key structural parameter set and the second key structural parameter set are determined to obtain the optimal key structural parameters.

[0034] Preferably, the expression of the stress function is:

[0035] F1(x)=(σ′ m -σ m ) 2 ;

[0036] Wherein, F1(x) is the stress function, x is the design variable, σ′ m is the mean stress of the initial simulation model, σ m is the mean stress of the final simplified model.

[0037] Preferably, the strain function is expressed as:

[0038] F2(x)=(ε′ m -ε m ) 2 ;

[0039] Wherein, F2(x) is the strain function, ε′ m is the mean strain of the initial simulation model, ε m is the mean strain of the final simplified model.

[0040] Preferably, the expression of the design variable is:

[0041]

[0042] Wherein, W1 and W2 are respectively the first width parameter and the second width parameter, H1 and H2 are respectively the first height parameter and the second height parameter, and T is the thickness parameter.

[0043] The present invention discloses the following technical effects:

[0044] The present invention provides a design method for a thermo-mechanical coupling equivalent simulation part at a characteristic position of a cylinder head, comprising:

[0045] Determine the structural features of the cylinder head to be simulated and obtain the stress-strain distribution under the thermal-engine coupling of the cylinder head to be simulated; according to the structural features, use the regional suppression method to simplify the model of the cylinder head to be simulated to obtain the final simplified model; determine the stress-strain mean of the final simplified model according to the stress-strain distribution under the thermal-engine coupling of the cylinder head to be simulated; establish the corresponding initial equivalent simulation model according to the structural size parameters of the structural features and the final simplified model; determine the stress-strain distribution of the initial equivalent simulation model to obtain the stress-strain mean of the initial equivalent simulation model; use the stress-strain mean of the final simplified model to optimize the stress-strain mean of the initial equivalent simulation model to obtain the optimal key structural parameters of the initial equivalent simulation model, wherein the key structural parameters include: width parameter, height parameter and thickness parameter; design the final equivalent simulation model according to the optimal key structural parameters. Focus on the key structural feature of the nose bridge area of ​​the cylinder head, and construct the corresponding small test piece around this feature. This design method can perform more accurate and efficient fatigue performance analysis on the cylinder head while maintaining the consistency of key structural parameters and shapes. In the thermal-mechanical coupling simulation process, an equivalent load application method is used to simulate the complex thermodynamic and mechanical loads that the cylinder head bears during actual operation, thereby improving the accuracy of the simulation results. In order to ensure that the simulation part is closer to the actual cylinder head in structure, the influence of the cooling water channel is specially considered, and the actual shape of the water channel section is accurately restored. Through this sophisticated design, the temperature distribution and thermal stress state of the cylinder head under actual working conditions can be captured more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 A flow chart of a design method for a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head provided by an embodiment of the present invention;

[0048] Figure 2 A cross-sectional view of the nose bridge area of ​​a cylinder head provided by an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of structural parameters of an equivalent simulation part of the nose bridge area of ​​a cylinder head provided by an embodiment of the present invention;

[0050] Figure 4 A schematic diagram of the structure of an equivalent simulation component of the nose bridge area of ​​a cylinder head provided by an embodiment of the present invention;

[0051] Figure 5 A detailed design diagram of an equivalent simulation part for the nose bridge area of ​​a cylinder head provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] like Figure 1 As shown, the present invention provides a design method for a thermo-mechanical coupling equivalent simulation part at a characteristic position of a cylinder head, comprising:

[0055] Step 100: determining the structural features of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling;

[0056] Step 200: simplifying the model of the cylinder head to be simulated by using a regional suppression method according to the structural features to obtain a final simplified model;

[0057] Step 300: determining the stress and strain mean value of the final simplified model according to the stress and strain distribution under the thermal-mechanical coupling of the cylinder head to be simulated;

[0058] Step 400: establishing a corresponding initial equivalent simulation component model according to the structural dimension parameters of the structural feature and the final simplified model;

[0059] Step 500: determining the stress-strain distribution of the initial equivalent simulation component model, and obtaining the stress-strain mean value of the initial equivalent simulation component model;

[0060] Step 600: optimizing the stress-strain mean of the initial equivalent simulation model using the stress-strain mean of the final simplified model to obtain the optimal key structural parameters of the initial equivalent simulation model, wherein the key structural parameters include: width parameter, height parameter and thickness parameter;

[0061] Step 700: Designing a final equivalent simulation component model according to the optimal key structural parameters.

[0062] Furthermore, the step of determining the structural features of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling includes:

[0063] determining a nose bridge region as a structural feature of the simulated cylinder head;

[0064] Performing finite element network division on the cylinder head to be simulated, wherein the structural feature area is divided by a high-density network;

[0065] Apply appropriate thermal boundary conditions to each area of ​​the cylinder head to be simulated after dividing the network units to obtain the temperature field distribution of the cylinder head;

[0066] The thermal stress field is obtained according to the temperature field distribution

[0067] The maximum alternating working load and assembly load are superimposed to obtain the coupled stress field;

[0068] The stress-strain distribution is determined according to the thermal stress field and the coupled stress field.

[0069] Specifically, the structural features of the cylinder head to be simulated are extracted and the stress-strain distribution under thermal-mechanical coupling is obtained:

[0070] The nose bridge area is a key characteristic position of the cylinder head of an internal combustion engine. It is subjected to the direct impact of high-temperature combustion gas and the complex flow of coolant during engine operation. It is the main area where thermal and mechanical stresses are concentrated in the cylinder head, and is therefore a prone area to fatigue damage. In related studies, by using fluid-solid coupling analysis of a single-sided cylinder head and a water jacket, it was found that the exhaust valve nose bridge area and the intake and exhaust valve nose bridge area showed the highest temperature and thermal stress levels in the cylinder head of an internal combustion engine, confirming the significant influence of this area on the fatigue damage of the cylinder head. Therefore, the present invention extracts the nose bridge area from the overall structure of the cylinder head as a characteristic position.

[0071] For the cylinder head, a component with a complex structure, the cylinder head model is first divided into detailed finite element meshes using pre-processing software such as Hypermesh. Tetrahedral meshes are selected, and the density of the mesh is especially increased in the characteristic position of the nose bridge area. Relatively sparse meshes are used in other parts to optimize the allocation of computing resources. Then, with the help of finite element simulation software such as Abaqus, the corresponding thermal boundary conditions are applied according to different areas of the cylinder head to obtain the temperature field distribution of the cylinder head, and the thermal stress field of the cylinder head is further calculated. Finally, on the basis of the thermal stress field, the assembly loads such as the maximum alternating working load and bolt preload are superimposed, while maintaining the consistency of the boundary constraints, and the coupled stress field of the cylinder head is calculated. The calculation results need to pay special attention to the highest stress-strain level and the average stress-strain level experienced in the structural characteristic area, and use them as the equivalent basis for the equivalent simulation parts.

[0072] Furthermore, according to the structural features, the model of the cylinder head to be simulated is simplified by using a regional suppression method to obtain a final simplified model, including:

[0073] Simplifying the intake and exhaust valves of the cylinder head model to obtain a first simplified model;

[0074] Simplifying the bolt holes, pin holes and ribs of the first simplified model to obtain a second simplified model;

[0075] The concave platforms and convex platforms of the second simplified model are simplified to obtain a final simplified model.

[0076] Specifically, the model simplification of the cylinder head to be simulated: The present invention mainly studies the stress and strain of the characteristic position nose bridge area, so it mainly simplifies the structure that deviates from the nose bridge area and the load application position. The regional suppression model simplification method is used to simplify each area, suppress each complex unnecessary area in the model, generate a simplified version of the original model, and retain the rough shape of the original model, as follows:

[0077] Simplification of intake and exhaust valves. Due to the different structures and functions of the intake and exhaust valves, in order to reduce the difficulty of intake and increase the intake volume, the intake valve is larger in diameter than the exhaust valve in the actual cylinder head structure. The present invention simplifies them by unifying their diameters.

[0078] Simplification of bolt holes, pin holes, ribs, etc. Bolt holes, pin holes, ribs, etc. that deviate from the load application position and have little effect on the temperature and stress field distribution are simplified.

[0079] Simplification of concave and convex platforms. The concave platform is simplified by filling it according to the outer contour surface of the cylinder head, and the convex structure is flattened to construct a new model surface for simplification.

[0080] Further, such as Figure 2-5 As shown, the cross section of the equivalent simulation part model is a T-shaped cross section.

[0081] Specifically, record the structural dimension parameters of the characteristic position, establish the dimension relationship, and design the initial equivalent simulation model: Figure 2 The schematic diagram of the structure of the flow channel in the water cavity of the actual nose bridge area of ​​the intake and exhaust valves is shown. The T-shaped cross-section part is the nose bridge area. Starting from the flow channel, the present invention abstracts a simplified nose bridge area structure with a T-shaped water cavity cross-section. By extracting the structural dimension parameters of the characteristic position and corresponding them to the dimension parameters of the subsequent equivalent simulation parts, a clear dimensional relationship is established. The specific corresponding relationship is as follows: the distance between the intake and exhaust channels is W1, corresponding to the total width of the equivalent simulation part; the distance between the intake and exhaust valve seats is W2, corresponding to the width of the lower half of the T-type equivalent simulation part; the thickness of the cylinder head is H1, corresponding to the total height of the equivalent simulation part; the length of the intake and exhaust channels is H2, corresponding to the height of the upper half of the T-type equivalent simulation part; assuming that the distance between the cooling water channel and the intake and exhaust channels, the intake and exhaust valve seats, the top surface of the cylinder head and the bottom surface of the cylinder head is the same, it uniformly corresponds to the thickness T of the equivalent simulation part; the total length L of the equivalent simulation part is consistent with the diameter of the intake and exhaust valve seats.

[0082] According to the size correspondence, the initial equivalent simulation model is designed and the following three principles are followed:

[0083] The key structural parameters are the same as the shape. The use of a simulated part with integrated cooling channels can simulate the real cylinder head more accurately in structure. The simulation part is designed with a T-shaped cross-section to be as close as possible to the actual shape of the cooling channels in the nose area. This simplification is applicable to almost all cooling channels in the nose area of ​​direct injection diesel engine cylinder heads. The key structural parameters are width parameters W1, W2, height parameters H1, H2, thickness parameter T, and length parameter L.

[0084] Same material properties. The cylinder head material is an important factor affecting its fatigue performance, and the same material as the real cylinder head should be selected.

[0085] The boundary conditions are the same. The boundary conditions of the cylinder head nose area directly affect the magnitude of static stress and alternating stress, which in turn affects its fatigue performance. By ensuring that the boundary conditions of the simulation are the same as those of the actual cylinder head, the stress state and fatigue characteristics of the simulation can be ensured to be similar to those of the actual cylinder head, thereby improving the reliability and practicality of the simulation results.

[0086] Furthermore, the stress-strain distribution is obtained by thermal-mechanical coupling simulation of the equivalent simulation part: Based on the equivalent simulation part model, Abaqus and other software are used to perform thermal-mechanical coupling simulation analysis. The meshing method, operating parameters, material selection, load constraints and boundary conditions are consistent with step two. The stress-strain gradient distribution of the equivalent simulation part is obtained, and the average stress-strain level is selected as the main evaluation indicator.

[0087] Furthermore, the method for obtaining the optimal key structural parameters is:

[0088] determining a first set of key structural parameters according to the stress function;

[0089] determining a second set of key structural parameters according to the strain function;

[0090] The minimum values ​​of the parameters corresponding to the first key structural parameter set and the second key structural parameter set are determined to obtain the optimal key structural parameters.

[0091] Furthermore, the expression of the stress function is:

[0092] F1(x)=(σ′ m -σ m ) 2 ;

[0093] Wherein, F1(x) is the stress function, x is the design variable, σ′ m is the mean stress of the initial simulation model, σ m is the mean stress of the final simplified model.

[0094] Furthermore, the expression of the strain function is:

[0095] F2(x)=(ε′ m -ε m ) 2 ;

[0096] Wherein, F2(x) is the strain function, ε′ m is the mean strain of the initial simulation model, ε m is the mean strain of the final simplified model.

[0097] Furthermore, the expression of the design variable is:

[0098]

[0099] Wherein, W1 and W2 are respectively the first width parameter and the second width parameter, H1 and H2 are respectively the first height parameter and the second height parameter, and T is the thickness parameter.

[0100] Specifically, the structural parameters of equivalent simulation parts are optimized:

[0101] According to the stress-strain mean of the structural characteristics of the cylinder head to be simulated, the optimization design method is used to design the equivalent simulation part structure of the cylinder head nose bridge area.

[0102] The key structural parameters of the equivalent simulation parts are used as design variables; the objective function of the optimization design is determined. The average stress-strain σ of the structural characteristics m , ε m As the optimization target, the average stress strain σ' of the equivalent simulation part m , ε' m With σ m , ε m Equal or similar; for multi-objective optimization problems, the hierarchical sequence method can be used to solve them. The main objective function is the stress function F1(x), and the secondary objective function is the strain function F2(x). Solve each objective function in turn to obtain the optimal structural parameters.

[0103] The optimal equivalent simulation part is constructed based on the optimal structural parameter combination corresponding to the minimum value of the stress and strain function. After the design is completed, the test pieces are accurately made according to the simulation part model, and these test pieces will be used for subsequent thermal-mechanical coupling fatigue tests.

[0104] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0105] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A design method for a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head, characterized in that: include: Determining the structural characteristics of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling; According to the structural features, a regional suppression method is used to simplify the model of the cylinder head to be simulated to obtain a final simplified model; Determining the stress and strain mean value of the final simplified model according to the stress and strain distribution of the cylinder head to be simulated under the thermal-mechanical coupling; Establishing a corresponding initial equivalent simulation component model according to the structural dimension parameters of the structural features and the final simplified model; Determining the stress and strain distribution of the initial equivalent simulation component model to obtain the stress and strain mean of the initial equivalent simulation component model; Optimizing the stress-strain mean of the initial equivalent simulation model using the stress-strain mean of the final simplified model to obtain the optimal key structural parameters of the initial equivalent simulation model, wherein the key structural parameters include: width parameter, height parameter and thickness parameter; The final equivalent simulation component model is designed according to the optimal key structural parameters.

2. The design method of a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head according to claim 1, characterized in that: The step of determining the structural features of the cylinder head to be simulated and obtaining the stress-strain distribution of the cylinder head to be simulated under thermal-mechanical coupling includes: determining a nose bridge region as a structural feature of the simulated cylinder head; Performing finite element network division on the cylinder head to be simulated, wherein the structural feature area is divided by a high-density network; Apply appropriate thermal boundary conditions to each area of ​​the cylinder head to be simulated after dividing the network units to obtain the temperature field distribution of the cylinder head; The thermal stress field is obtained according to the temperature field distribution The maximum alternating working load and assembly load are superimposed to obtain the coupled stress field; The stress-strain distribution is determined according to the thermal stress field and the coupled stress field.

3. The design method of a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head according to claim 1, characterized in that: The method of simplifying the model of the cylinder head to be simulated by adopting a regional suppression method according to the structural characteristics to obtain a final simplified model includes: Simplifying the intake and exhaust valves of the cylinder head model to obtain a first simplified model; Simplifying the bolt holes, pin holes and ribs of the first simplified model to obtain a second simplified model; The concave platforms and convex platforms of the second simplified model are simplified to obtain a final simplified model.

4. The design method of a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head according to claim 1, characterized in that: The cross section of the equivalent simulation part model is a T-shaped cross section.

5. The design method of a thermo-mechanical coupling equivalent simulation component at a characteristic position of a cylinder head according to claim 1, characterized in that: The method for obtaining the optimal key structural parameters is: determining a first set of key structural parameters according to the stress function; determining a second set of key structural parameters according to the strain function; The minimum values ​​of the parameters corresponding to the first key structural parameter set and the second key structural parameter set are determined to obtain the optimal key structural parameters.

6. The design method of the thermo-mechanical coupling equivalent simulation component at the characteristic position of the cylinder head according to claim 5 is characterized in that: The expression of the stress function is: F1(x)=(σ′ m -s m ) 2 ; Wherein, F1(x) is the stress function, x is the design variable, σ′ m is the mean stress of the initial simulation model, σ m is the mean stress of the final simplified model.

7. The design method of the thermo-mechanical coupling equivalent simulation component at the characteristic position of the cylinder head according to claim 5 is characterized in that: The expression of the strain function is: F2(x)=(ε′ m -ε m ) 2 ; Wherein, F2(x) is the strain function, ε′ m is the mean strain of the initial simulation model, ε m is the mean strain of the final simplified model.

8. The design method of the thermo-mechanical coupling equivalent simulation component at the characteristic position of the cylinder head according to claim 6 is characterized in that: The expressions of the design variables are: Wherein, W1 and W2 are respectively the first width parameter and the second width parameter, H1 and H2 are respectively the first height parameter and the second height parameter, and T is the thickness parameter.

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