Creation method of finite element model of electronic device and simulation method of electronic device

Abstract

The invention belongs to the technical field of computer aided design, and provides a method for creating a finite element model of an electronic device and a method for simulating the electronic device.In the stress calculation method for the circuit board welding process, the whole electronic device is divided into a device body and a connecting structure, homogenization simplified modeling is conducted on the device body and the connecting structure, and therefore the stress of the device body and the connecting structure is obtained; the orthotropic material is used for calculating equivalent thermal and mechanical parameters, so that the number of grids in the simulation process can be effectively reduced, the calculation speed is improved, and the problem that a complex circuit board assembly is difficult to model and simulate is solved. And through finite element simulation comparison, the availability of the method is verified.

Description

Technical Field

[0001] This application belongs to the technical field of computer-aided design. Specifically, it relates to a method for creating a finite element model of an electronic device and a method for simulating an electronic device. Background Art

[0002] In order to achieve high performance, low cost, and miniaturization, the integrated circuit system-level packaging structure must have high reliability and durability. Especially in some emerging application scenarios, such as the field of intelligent vehicles, integrated circuits must work in high-vibration, high-temperature, or low-temperature environments, posing new challenges to the reliability and durability of the system-level packaging structure. Currently, the design and optimization of the integrated circuit system-level packaging structure mainly rely on experiments and experience. However, the experimental cost is high, the cycle is long, and the influence of design parameters cannot be comprehensively considered. Empirical design cannot guarantee the optimal design effect. Therefore, an accurate, efficient, and economical design and optimization method is needed to meet the requirements of the integrated circuit system-level packaging structure. Summary of the Invention

[0003] This application provides a method for creating a finite element model of an electronic device and a method for simulating an electronic device, which can improve the calculation speed, the model is available, and solves the problem that it is difficult to model and simulate complex circuit board components.

[0004] Among them, for the method for creating a finite element model of an electronic device, the electronic device includes a main body and a plurality of pins or solder balls for connecting the main body to a PCB. The main body includes a housing and a plurality of components inside the housing. The creating method includes:

[0005] S1: According to the shape parameters and material parameters of the components inside the housing, unify the housing of the main body and the components inside the housing into an orthotropic main body model, and the geometric parameters of the main body model are the same as the geometric parameters of the housing of the main body;

[0006] S21: Unify a plurality of the pins on the same side of the main body into an orthotropic pin model, and the pin model is a geometric body with a constant cross-section; or S22: Unify a plurality of the solder balls into an orthotropic solder ball model, and the solder ball model is a cuboid;

[0007] S3: Connect the main body model and the pin model or the solder ball model as the finite element model of the electronic device.

[0008] In one embodiment, the length of the pin model is the distance between the outer end faces of the pins at both ends of the same side.

[0009] In one embodiment, the calculation method of the material parameters of the pin model includes:

[0010] S2101: Create an original structure model, where the original structure model includes the main body model, a pin fine model consistent with the actual structure, and a PCB;

[0011] S2102: Adopt a static analysis step, restrict all degrees of freedom of the two end faces of the PCB parallel to its board surface in the x - direction except for the movement in the x - direction, apply a concentrated force with a magnitude of f and a direction of the negative z - direction at the mid - point of the bottom of the PCB; Select four corner points on the bottom surface of the main body model, and points on the top surface of the PCB that have the same x and y coordinates as these four corner points before the force is applied, and record the z - direction distance between the four corner points and the corresponding points on the PCB after the concentrated force is applied;

[0012] S2103: Replace the pin fine model in the original structure model with a pin model, and apply the same constraints and forces to the PCB board as in S2102;

[0013] S2104: Adjust the material parameters of the pin model so that the z - direction distance between the four corner points on the bottom surface of the pin model and the corresponding points on the PCB is equal to the data recorded in S2102, and use the material parameters of the pin model at this time as its material parameters.

[0014] In one embodiment, the outer contour of the solder ball model is consistent with the outer contour dimensions of all the solder balls.

[0015] In one embodiment, the method for calculating the material parameters of the solder ball model includes:

[0016] S2201: Create an original structure model, where the original structure model includes the main body model, a solder ball fine model consistent with the actual structure, and a PCB;

[0017] S2202: Adopt a static analysis step, restrict all degrees of freedom of the two end faces of the PCB parallel to its board surface in the x - direction except for the movement in the x - direction, apply a concentrated force with a magnitude of f and a direction of the negative z - direction at the mid - point of the bottom of the PCB; Select four corner points on the bottom surface of the main body model, and points on the top surface of the PCB that have the same x and y coordinates as these four corner points before the force is applied, and record the z - direction distance between the four corner points and the corresponding points on the PCB after the concentrated force is applied;

[0018] S2203: Replace the solder ball fine model in the original structure model with a solder ball model, and apply the same constraints and forces to the PCB board as in S2202;

[0019] S2204: Adjust the material parameters of the solder ball model so that the z - direction distance between the four corner points on the bottom surface of the solder ball model and the corresponding points on the PCB is equal to the data recorded in S2202, and use the material parameters of the solder ball model at this time as its material parameters.

[0020] In one embodiment, the density within the main body model is the same, and the density of the main body model is determined according to the volume occupied by the components of different materials within the main body.

[0021] The specific heat capacity within the main body model is the same, and the specific heat capacity of the main body model is determined according to the volume occupied by the components of different specific heat capacities within the main body.

[0022] In one embodiment, the thermal conductivity of the main body model is orthotropic and corresponds to the thermal conductivities in three orthogonal directions of the main body.

[0023] The mechanical parameters of the main body model are orthotropic and correspond to the mechanical parameters in three orthogonal directions of the main body.

[0024] The thermal expansion coefficient of the main body model is orthotropic and corresponds to the thermal expansion coefficients in three orthogonal directions of the main body.

[0025] Among them, the mechanical parameters of the main body model include shear modulus.

[0026] This application also provides a simulation method for an electronic device, and creates the finite element model of the electronic device through the method for creating the finite element model of the electronic device.

[0027] This application also provides a computer-readable storage medium, which stores the method for creating the finite element model of the electronic device.

[0028] This application also provides a computer program product, which executes the method for creating the finite element model of the electronic device when running.

[0029] In the stress calculation method for the circuit board welding process provided by this application, the electronic device is divided into two parts, namely the device main body and the connection structure, for homogenization and simplified modeling respectively. Orthotropic materials are used to calculate the equivalent thermal and mechanical parameters, which can effectively reduce the number of grids in the simulation process, improve the calculation speed, and solve the problem of difficult modeling and simulation for complex circuit board components. And through finite element simulation comparison, the usability of this method is verified.

[0030] For further clear elaboration, aspects and advantages of the embodiments disclosed in this application will become apparent in the following description part, or be understood through the practice of the embodiments disclosed in this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are used to provide further understanding of this application, and constitute a part of the specification. Together with the following specific implementation manners, they are used to explain the present invention, but do not constitute a limitation to the present invention.

[0032] Figure 1 It is a logical flowchart of the method for creating a finite element model of an electronic device provided in Embodiment 1 of the present application;

[0033] Figure 2 (a) and Figure 2 (b) are schematic diagrams of the pin structure to be modeled and its pin model in Embodiment 1 of the present application;

[0034] Figure 3 It is a schematic diagram of the original structure model created in S2101 in Embodiment 1 of the present application;

[0035] Figure 4 a) and Figure 4 (b) are schematic diagrams of the solder ball structure to be modeled and its pin model in Embodiment 1 of the present application;

[0036] Figure 5 It is a schematic diagram of the original structure model created in S2201 in Embodiment 1 of the present application;

[0037] Figure 6 It is a schematic diagram of the boundary conditions of the fine model X-direction thermal conductivity calculation example in Embodiment 1 of the present application;

[0038] Figure 7 It is the boundary conditions of the fine model elastic modulus calculation example in Embodiment 1 of the present application: (a) X-direction tensile boundary condition; (b) Y-direction tensile boundary condition; (c) Z-direction tensile boundary condition;

[0039] Figure 8 (a), (b) and (c) are the boundary conditions of the device body equivalent shear modulus calculation example in Embodiment 1 of the present application;

[0040] Figure 9 It is the boundary conditions of the fine model thermal expansion coefficient X-direction calculation example in Embodiment 1 of the present application;

[0041] Figure 10 (a) shows the fine model of the FP package type electronic device in Embodiment 1 of the present application and Figure 10 (b) shows the equivalent model of the FP package type electronic device

[0042] Figure 11 Schematic diagram of the comparison and verification boundary conditions between the fine model and the equivalent model: (a) x-direction boundary condition; (b) y-direction boundary condition. Detailed implementation manners

[0043] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0044] Embodiment 1

[0045] This embodiment provides a method for creating a finite element model of an electronic device. The electronic device includes a main body and a plurality of pins or solder balls for connecting the main body to a PCB. The main body includes a housing and a plurality of components inside the housing, such as Figure 1 As shown, the creation method includes:

[0046] S1: Unify the housing of the main body and the components inside the housing into an orthotropic main body model according to the shape parameters and material parameters of the components inside the housing. The geometric parameters of the main body model are the same as those of the housing of the main body;

[0047] In S1, ignoring the internal structure of the main body of the electronic device, according to the housing contour shape, keeping the external dimensions consistent, it is simplified into a solid homogeneous structure, without any further regional division, and only one orthotropic material is used to describe its thermal and mechanical behaviors.

[0048] S21: Unify a plurality of the pins on the same side of the main body into an orthotropic pin model, and the pin model is a geometric body with a constant cross-section; or S22: Unify a plurality of the solder balls into an orthotropic solder ball model, and the solder ball model is a cuboid;

[0049] In S21 and S22, for a large number of device connection structures (including pins and solder balls), according to the contour dimensions of their covered areas, they are simplified into solid structures with regular shapes and uniform materials, and only one orthotropic material is used to describe their thermal and mechanical behaviors.

[0050] Specifically, the length of the pin model is the distance between the outer end faces of the pins at both ends of the same side; the outer contour of the solder ball model is the same as the outer contour dimensions of all the solder balls.

[0051] S3: Connect the main body model and the pin model or the solder ball model as the finite element model of the electronic device.

[0052] As a preferred implementation, for the pin structure as shown in Figure 2 (a), it is simplified using continuous Shell elements as shown in Figure 2 (b). The length of the pin model is the distance between the outer end faces of the pins at both ends of the same side. The original material of the pins is Cu, and the material of the pin model is assumed to be an orthotropic material. Mesh generation and material assignment are completed in Hypermesh.

[0053] The calculation method of the material parameters of the pin model includes:

[0054] S2101: Use Hypermesh to create the original structure model, which includes the main body model, a pin fine model consistent with the actual structure, and a PCB, as Figure 3 shown;

[0055] S2102: Adopt a static analysis step to restrict all degrees of freedom of the two end faces of the PCB parallel to its board surface in the x direction except for the movement in the x direction, and apply a concentrated force with a magnitude of f and a direction of the negative z direction to the midpoint of the bottom surface of the PCB; Select four corner points A on the bottom surface of the main body model, and points B on the top surface of the PCB that have the same x and y coordinates as these four corner points before the force is applied, and record the z-direction distance between the four corner points A and the corresponding points B on the PCB after the concentrated force is applied;

[0056] S2103: Replace the pin fine model in the original structure model with a pin model, and apply the same constraints and forces to the PCB as in S2102;

[0057] S2104: Adjust the material parameters of the pin model so that the z-direction distance between the four corner points on the bottom surface of the pin model and the corresponding points on the PCB is equal to the data recorded in S2102, and use the material parameters of the pin model at this time as its material parameters.

[0058] As a preferred embodiment, for the pin structure shown in Figure 4 (a), use continuous Shell elements to simplify it, as shown in Figure 4 (b). The solder ball model constructs a rectangular parallelepiped structure with the same height as the solder balls according to the outer boundaries of all solder balls and with regular shapes along its outer edges. The solder balls use tin-lead solder, and the material of the equivalent connection structure is assumed to be orthotropic.

[0059] The pin model uses special shell elements, which are different from the element types of other structures. Through calculation verification, the shell elements can also ensure the calculation accuracy. At the same time, the shell elements can greatly reduce the number of elements and improve the calculation speed.

[0060] The calculation method of the material parameters of the solder ball model includes:

[0061] S2201: Use Hypermesh to create the original structure model, which includes the main body model, a solder ball fine model consistent with the actual structure, and a PCB, as Figure 5 shown;

[0062] S2202: Apply a static analysis step to restrict all degrees of freedom of the two end faces of the PCB parallel to its board surface in the x - direction except for the movement in the x - direction, and apply a concentrated force with a magnitude of f and a direction of the negative z - direction to the mid - point of the bottom of the PCB; select four corner points C on the bottom surface of the main body model, and points D on the top surface of the PCB with the same x and y coordinates as these four corner points before loading, and record the z - direction distance between the four corner points C and the corresponding points D on the PCB after applying the concentrated force;

[0063] S2203: Replace the fine model of the solder ball in the original structure model with a solder ball model, and apply the same constraints and forces to the PCB board as in S2202;

[0064] S2204: Adjust the material parameters of the solder ball model so that the z - direction distance between the four corner points on the bottom surface of the solder ball model and the corresponding points on the PCB is equal to the data recorded in S2202, and use the material parameters of the solder ball model at this time as its material parameters.

[0065] This application also provides an equivalent material parameter calculation method for calculating the thermal and mechanical parameters of the orthotropic equivalent material of the main body part of the device.

[0066] The density within the main body model is the same. Determine the density of the main body model according to the volume occupied by the devices of different materials within the main body;

[0067] The specific heat capacity within the main body model is the same. Determine the specific heat capacity of the main body model according to the volume occupied by the devices with different specific heat capacities within the main body.

[0068] The thermal conductivity of the main body model is orthotropic and corresponds equally to the thermal conductivities of the main body in three orthogonal directions.

[0069] The mechanical parameters of the main body model are orthotropic and correspond equally to the mechanical parameters of the main body in three orthogonal directions;

[0070] The thermal expansion coefficient of the main body model is orthotropic and corresponds equally to the thermal expansion coefficients of the main body in three orthogonal directions.

[0071] The mechanical parameters of the main body model include the shear modulus.

[0072] Specifically, to calculate the temperature field, first solve the heat conduction differential equation, which clarifies the relationship between the temperature distribution of an object and space and time, and derive the three - dimensional unsteady heat conduction differential equation in a rectangular coordinate system based on Fourier's equation and the law of conservation of energy:

[0073]

[0074] Among them, λ is the thermal conductivity; ρ is the density; c is the specific heat capacity, and Φ is the heat released by the heat source per unit volume per unit time. If there is no heat source inside, the value of this term is 0.

[0075] Since the calculation formula involves density, specific heat capacity, and thermal conductivity, before solving the temperature field, it is necessary to calculate parameters such as equivalent density in advance.

[0076] In actual situations, an electronic device is an object with non-uniform internal distribution. Using the homogenization method, according to the density and volume ratio of different substances, homogenization calculation can be carried out to obtain the calculation formula for equivalent density:

[0077]

[0078] Among them, V i is the volume of each material inside the device; ρ i is the density of each material inside the device; V is the total volume of the device.

[0079] Use mainstream CAD modeling software such as Solidworks to accurately calculate the volume of different materials that make up the device. According to the density and volume of different materials, substitute them into Equation (1.2) to calculate the equivalent density.

[0080] The equivalent specific heat capacity of the electronic device is also calculated by homogenization according to the specific heat capacity and volume ratio of different substances that make up the device, and the calculation formula for the equivalent specific heat capacity can be obtained:

[0081]

[0082] Among them, Q is the total heat absorbed or released by the device; M is the total mass of the device; ΔT is the temperature change of the device.

[0083] The total heat absorbed or released by the device is equal to the sum of the heat absorbed or released by each material inside:

[0084]

[0085] The heat Q absorbed or released by each material i can be calculated by Equation (1.5):

[0086] Q i =C i M i ΔT (1.5)

[0087] The total heat calculation formula can be integrated as

[0088]

[0089] Since the mass M i =ρ i Vi , the equivalent specific heat capacity calculation formula can be obtained by integration

[0090]

[0091] Among them, ρi is the density of each material in the device, Vi is the volume of each material in the device, Ci is the specific heat capacity of each material in the device, ρ is the equivalent density of the device, and V is the total volume of the device. Calculations can be directly carried out on the basis of the fine model.

[0092] Using mainstream CAD modeling software such as Solidworks, accurately calculate the volumes of different materials that make up the device. Combining the specific heat capacities of different materials, etc., the equivalent specific heat capacity of the main part of the device can be calculated according to Equation (1.7).

[0093] Similarly, the calculation formula for the equivalent thermal conductivity of the device:

[0094]

[0095] Among them, λi is the thermal conductivity of the device in the i-th direction, q″ i represents the heat flux in the i-th direction, is the temperature gradient in the i-th direction.

[0096] When the device shows different thermal conductivities in the three directions of the rectangular coordinate system x, y, and z, the equivalent thermal conductivity of the device can be assumed as an orthotropic parameter:

[0097]

[0098] In this implementation, it is not calculated through experimental or simulation results, but obtained through calculation formulas. Combining the structure and material parameters of the fine model, the equivalent density and equivalent specific heat capacity are directly calculated. Therefore, the creation method provided by this application saves the cost of experiments or simulations, improves efficiency, and because it is based on calculation formulas, experimental and simulation errors are avoided, further improving the accuracy of equivalent parameters.

[0099] Select the corresponding model of the device and create its fine finite element model. The fine model consists of structures such as the outer shell, top cover, and internal chips. Use Hypermesh software to mesh each component and assign corresponding materials, such as Figure 6 as shown.

[0100] Use ABAQUS or Ansys software to simulate the device and calculate the thermal conductivity of the device body in the x direction. Set the boundary conditions as Figure 6 shown. Set the temperature of the positive x face of the device body to 20 °C and the temperature of the negative x face to 40 °C, and perform a steady-state heat conduction analysis.

[0101] Record the heat flux in the x-direction in the simulation results, extract the heat fluxes of all nodes on the two end faces in the x-direction and take the average value. Substitute the average heat flux into Equation (1.8) to calculate the equivalent thermal conductivity λ1 in the x-direction.

[0102] The calculation process of the equivalent thermal conductivity of the main body of the device in the y-direction and z-direction is the same.

[0103] Next, calculate the mechanical parameters of the main body model of the device:

[0104] Considering the coefficient of thermal expansion, the matrix form of the generalized Hooke's law for anisotropic materials is

[0105]

[0106] where α i (i = x, y, z) is the coefficient of thermal expansion; ΔT is the temperature change of the object.

[0107] The strain components can be expressed by stress components, and the relational expression in matrix form is:

[0108]

[0109] Simplify the above formula for orthotropic materials with only 9 independent material parameters, and we can get

[0110]

[0111] where E1 is the elastic modulus of the material in the x-direction, E2 is the elastic modulus of the material in the y-direction, and E3 is the elastic modulus of the material in the z-direction. The subscript v represents the Poisson's ratio of the two corresponding directions, for example, v 12 represents the Poisson's ratio between the X-direction and the Y-direction, where v 12 = v 21 , v 23 = v 32 , v 13 = v 31 .

[0112] Separate the tensile deformation part and the shear deformation part for calculation, and the formula is

[0113]

[0114] Rewrite the constitutive equation:

[0115]

[0116] where, in which j represents applying a tensile load in the j-direction, and i represents the normal strain in the i-direction under the j-load, The representation method of is the same.

[0117] The Hypermesh software is used to mesh the fine device model and assign material properties, and the ABAQUS software is used to set boundary conditions, etc., for finite element analysis to assist in completing the equivalent of the device mechanical parameters.

[0118] To calculate the equivalent tensile elastic modulus and Poisson's ratio of the device, tensile boundary conditions are set as shown in Figure 7 (a), (b) and (c). First, the degrees of freedom in the i (i = x, y, z) direction of the negative end faces are respectively constrained, and at the same time, constraints are applied to these three faces. A surface force F j = 1 N is applied in the j (j = x or y or z) direction for stretching, and the displacement nephogram and stress nephogram of the device are calculated. The average displacement of all nodes on the positive end face in the k (k = x, y, z) direction is recorded as well as the average stress and . The superscript in the upper right corner indicates the surface force applied in the j direction, and the subscript in the lower right corner indicates the displacement or normal stress in the k direction. Finally, a total of 9 average stress values and 9 average displacement values are obtained, and substituting them into Equation (1.15), the equivalent elastic modulus and equivalent Poisson's ratio can be calculated.

[0119] The shear modulus of the model created in this embodiment is different in different directions. Considering the influence of the shear model, it is necessary to perform equivalent calculation of the shear modulus.

[0120] To calculate the equivalent shear model of the device, the shear boundary conditions shown in Figure 8 (a), (b) and (c) are applied to the device, restricting all degrees of freedom of the negative end face in the i (i = x or y or z) direction, and applying a shear force F ij (j = x, y, z and j ≠ i) to the positive end face in the i direction, and the strain nephogram and stress nephogram of the device are calculated. The average shear strain ε ij and the average shear stress σ ij of all nodes on the positive end face in the i direction are recorded. The corresponding shear strains and shear stresses are averaged, and a total of 3 shear strain values and 3 shear stress values are obtained, and substituting them into Equation (1.14), the equivalent shear model can be calculated.

[0121] To calculate the equivalent thermal expansion coefficient of the device, the boundary conditions shown in Figure 9 are applied to the device, restricting all degrees of freedom of the negative end face in the i (i = x or y or z) direction, setting the initial temperature of the main body of the device to 25 °C and the end temperature to 45 °C, and calculating the displacement nephogram of the device. The average displacement U i of the positive end face in the i direction of the device is recorded, and the equivalent thermal expansion coefficient in the i direction is calculated according to Equation (1.16).

[0122]

[0123] where ΔL = U i ; L i represents the initial length of the device in the i direction; ΔT represents the temperature change value.

[0124] To verify the correctness and accuracy of the above equivalent method, the equivalent model and the fine model are respectively simulated and their errors are compared.

[0125] As Figure 10 (a) shows the fine model of the FP package type electronic device and Figure 10 (b) shows the equivalent model of the FP package type electronic device. The same temperature load and external force load are applied to the fine model and the equivalent model. The load settings are as Figure 11 shown. A binding constraint is set between the electronic device model and the circuit board and they are assembled together. All degrees of freedom of the two end faces of the circuit board in the x direction except the x direction movement are constrained. The device temperature is set to rise from 20°C to 100°C, and a downward concentrated force F z = -10 N is applied to the midpoint of the bottom of the PCB board. Similarly, the same boundary conditions and loads are set for the y direction. Four corner points at the bottom of the device body and the application point of the concentrated force are selected, and the z-direction displacements U z of these five points are recorded. The results of the fine model are compared with the results of the equivalent model, and the results are shown in Table 1. The results show that under the force and thermal loads, the simulation errors in the x and y directions are both kept within 3%, proving the correctness and reliability of the homogenization equivalent method of this electronic device.

[0126] Table 1 Error analysis of the fine model and the equivalent model

[0127]

[0128] Example 2

[0129] This example provides a simulation method for an electronic device, and creates the finite element model of the electronic device by using the method for creating the finite element model of the electronic device provided in Example 1;

[0130] Example 3

[0131] This example provides a computer-readable storage medium, which stores the method for creating the finite element model of the electronic device provided in Example 1.

[0132] This example provides a computer program product, which executes the method for creating the finite element model of the electronic device provided in Example 1 when running.

[0133] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present technical solution and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present technical solution.

[0134] In the present technical solution, unless otherwise clearly defined and limited, terms such as "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present technical solution can be understood according to specific circumstances.

[0135] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present technical solution. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0136] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as a limitation to the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A method for creating a finite element model of an electronic device, wherein the electronic device comprises a main body and a plurality of pins or solder balls for connecting the main body to a PCB, wherein the main body comprises a housing and a plurality of components in the housing, wherein: The creation method comprises: S1: unifying the outer shell of the main body and the components inside the outer shell into an orthotropic main body model according to shape parameters and material parameters of the components inside the outer shell, wherein the geometric parameters of the main body model are the same as the geometric parameters of the outer shell of the main body; S21: unifying the plurality of pins on the same side of the main body into an orthotropic pin model, wherein the pin model is a uniform cross-sectional geometric body; or S22: unifying the plurality of solder balls into an orthotropic solder ball model, wherein the solder ball model is a cuboid; S3: Connecting the main body model and the pin model or the solder ball model as the finite element model of the electronic device.

2. The creation method according to claim 1, characterized in that: The length of the pin model is the distance between the outer end surfaces of the pins at the first and last ends of the side.

3. The creation method according to claim 2, characterized in that: The material parameter calculation method of the pin model includes: S2101: creating an original structure model, wherein the original structure model includes the main body model, a pin fine model consistent with the actual structure, and a PCB; S2102: Using the static analysis step, restrict all degrees of freedom of the two end surfaces of the PCB parallel to the x direction of its board surface except for the movement in the x direction, and apply a concentrated force of magnitude f and direction in the negative z direction to the midpoint of the bottom of the PCB; Select four corner points on the bottom surface of the main model and points on the top surface of the PCB that have the same x and y coordinates as the four corner points before the force is applied, and record the z-direction distances between the four corner points and the corresponding points on the PCB after the concentrated force is applied; S2103: replacing the pin fine model in the original structural model with the pin model, and applying the same constraints and forces as in S2102 to the PCB board; S2104: Adjust the material parameters of the pin model so that the z-direction distance between the four corner points on the bottom surface of the pin model and the corresponding points on the PCB is equal to the data recorded in S2102, and use the material parameters of the pin model at this time as its material parameters.

4. The creation method according to claim 1, characterized in that: The outer contour of the solder ball model is consistent with the outer contour size of all the solder balls.

5. The creation method according to claim 5, characterized in that: The material parameter calculation method of the solder ball model comprises: S2201: creating an original structure model, wherein the original structure model includes the main body model, a solder ball fine model consistent with the actual structure, and a PCB; S2202: Using the static analysis step, restrict all degrees of freedom of the two end surfaces of the PCB parallel to the x direction of its board surface except for the movement in the x direction, and apply a concentrated force of magnitude f and direction in the negative z direction to the midpoint of the bottom of the PCB; Select four corner points on the bottom surface of the main model and points on the top surface of the PCB that have the same x and y coordinates as the four corner points before the force is applied, and record the z-direction distances between the four corner points and the corresponding points on the PCB after the concentrated force is applied; S2203: replacing the solder ball fine model in the original structural model with the solder ball model, and applying the same constraints and forces as in S2202 to the PCB board; S2204: Adjust the material parameters of the solder ball model so that the z-direction distances between the four corner points on the bottom surface of the solder ball model and the corresponding points on the PCB are equal to the data recorded in S2202, and use the material parameters of the solder ball model at this time as its material parameters.

6. The creation method according to claim 1, characterized in that: The density in the main body model is the same, and the density of the main body model is determined according to the volume occupied by the components of different materials in the main body; The specific heat capacity in the main body model is the same, and the specific heat capacity of the main body model is determined according to the volume occupied by the devices with different specific heat capacities in the main body.

7. The creation method according to claim 1, characterized in that: The thermal conductivity of the main body model is orthotropic and corresponds to and is equal to the thermal conductivity of the main body in three orthogonal directions; The mechanical parameters of the main body model are orthogonal anisotropic and correspond to and are equal to the mechanical parameters of the main body in three orthogonal directions; The thermal expansion coefficient of the main body model is orthotropic and corresponds to and is equal to the thermal expansion coefficient of the main body in three orthogonal directions; Wherein, the mechanical parameters of the main model include shear modulus.

8. A method for simulating an electronic device, characterized in that: The electronic device finite element model is created by the method for creating an electronic device finite element model according to any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that A method for creating a finite element model of an electronic device according to any one of claims 1 to 7.

10. A computer program product, characterized in that The method for creating a finite element model of an electronic device according to any one of claims 1 to 7 is executed during runtime.

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