Calculation method of FPC current-carrying capacity finite element model, electronic equipment and storage medium
By establishing a three-dimensional model of FPC and performing finite element simulation, the problem of the lack of standards for FPC current carrying capacity calculation was solved, enabling rapid and economical current carrying capacity assessment, shortening the development cycle and reducing costs.
Patent Information
- Application Number
- CN202411293701.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-14
- Publication Date
- 2025-01-24
AI Technical Summary
The lack of existing standards for calculating the rated current carrying capacity of FPCs makes it impossible to effectively guide production in the FPC field.
Establish a three-dimensional model of the FPC, set physical parameters and boundary conditions, perform simulation calculations through the finite element model, obtain the temperature rise results of the FPC and determine whether they meet the design requirements, and output the current carrying capacity value.
Without requiring finished product testing, it can preliminarily determine the current carrying capacity of FPC circuits, shorten the development cycle, reduce manufacturing costs, and provide reliable methods for calculating current carrying capacity and temperature rise.
Smart Images
Figure CN119358307A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of FPC current carrying capacity, and in particular to a calculation method of a finite element model of FPC current carrying capacity, an electronic device and a storage medium. Background Art
[0002] In the manufacturing process of circuits and electrical appliances, the overload capacity of copper wires needs to be estimated and tested to ensure the absolute safety of circuits and cables in actual applications and avoid overcurrent.
[0003] At present, in the field of printed circuit boards (PCBs) and high-voltage cables, there are corresponding reference standards for the overload capacity of copper wires to preliminarily determine the current-carrying capacity of cables. For example, in the field of printed circuit board (PCB) manufacturing and high-voltage cable, there are corresponding reference standards to preliminarily determine the current-carrying capacity of cables. PCBs can refer to the traditional IPC-2221 standard to determine the current-carrying capacity I of PCBs; in electrical cables, the calculation standard for the rated current carrying capacity of cables can refer to the authoritative standard document IEC 60287. However, at present, the calculation of the rated current carrying capacity of FPCs is still in a blank stage, and there are no relevant reference standards and estimation methods, which makes it impossible to estimate the rated current carrying capacity in the FPC field, and thus it is impossible to provide effective guidance for actual production. Summary of the invention
[0004] Based on this, it is necessary to provide a calculation method, electronic device and storage medium for a finite element model of FPC current carrying capacity.
[0005] An embodiment of the present invention provides a method for calculating a finite element model of an FPC current carrying capacity, comprising the following steps:
[0006] S1. Establish a three-dimensional model of FPC;
[0007] S2, establishing a first functional relationship corresponding to the FPC current carrying capacity model, and setting physical parameters that affect the FPC current carrying capacity;
[0008] S3, setting physical field parameters and establishing boundary conditions;
[0009] S4, meshing the three-dimensional model to obtain a finite element model;
[0010] S5, setting a time step transient solver for the finite element model, and performing simulation calculations using an iterative solution method to obtain a simulation result of the finite element model;
[0011] S6. Perform post-processing analysis on the simulation results of the finite element model to obtain the FPC temperature rise results, and determine whether the FPC temperature rise results meet the design requirements. If not, return to step S3; if satisfied, end the calculation and directly output the FPC current value.
[0012] Preferably, in step S1, a three-dimensional model of the FPC is established using 3D drawing software, and the established three-dimensional model is exported from the 3D drawing software as a file in ODB++ format, and the 3D drawing software is any one of Solid Works, CAD, and CATIA.
[0013] Preferably, in step S2, the physical parameters include the copper thickness of the FPC circuit, the line width of the FPC circuit, and the temperature rise of the FPC circuit.
[0014] Preferably, in step S2, the first functional relationship is:
[0015] I max =α*ΔT β *[(1+γ(W-1.0))]
[0016] Among them, I max is the maximum current carrying value within the allowable temperature rise range of FPC, in units of A; ΔT is the allowable temperature rise of FPC, in units of ℃; W is the design line width of FPC, in units of mm; where α is the first judgment constant, β is the first judgment index, and γ is the second judgment index.
[0017] Preferably, the copper thickness is (28-42) um and the temperature rise is (10-40) °C.
[0018] Preferably, in step S4, after the three-dimensional model is meshed, the mesh division is coarsened.
[0019] Preferably, the post-processing analysis specifically includes:
[0020] S501, processing the simulation result of the FPC three-dimensional model into a transient temperature distribution cloud map of the temperature field;
[0021] S502, inserting a domain point probe into the transient temperature distribution cloud map to monitor the real-time temperature rise dynamics of the FPC before the temperature reaches a steady state, thereby obtaining FPC temperature rise data.
[0022] Preferably, the transient solver is any one of a direct solver, an iterative solver, a conjugate gradient solver or a FGMRES solver.
[0023] The present invention provides an electronic device, comprising a processor and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the described method is executed.
[0024] The present invention provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the method described above is executed.
[0025] The method of the present invention can estimate the overload condition of the FPC within the allowable temperature rise range through simulation in a finite element simulation environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above and other purposes, features and advantages of the present invention will become more clear by more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the accompanying drawings are not deliberately scaled to the actual size, and the focus is on illustrating the main purpose of the present invention.
[0027] Figure 1 A flowchart of a method according to a preferred embodiment of the present invention;
[0028] Figure 2 2 is a diagram showing the structure of a device according to an embodiment of the present invention. DETAILED DESCRIPTION
[0029] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.
[0030] like Figure 1 As shown, a method for developing a finite element model for calculating the current carrying capacity of an FPC is provided, comprising the following steps:
[0031] S1. Establish a 3D model of FPC, which is a 3D geometric model. The 3D model of the flexible circuit board can be constructed through CAD software and exported as an ODB++ file. The established 3D model refers to the designed Layout drawing, and the copper thickness value is set in the thickness direction by geometric stretching to obtain the 3D model.
[0032] S2. Establish a first functional relationship, which is a first functional relationship corresponding to the FPC current carrying capacity model, and set physical parameters; the FPC current carrying capacity model is the three-dimensional model in step S1.
[0033] S3. Set the physical field parameters and establish boundary conditions. The physical field parameters include external environment temperature, initial temperature, FPC convection heat transfer coefficient, FPC initial voltage, conductivity, density and thermal conductivity. Accurate boundary conditions can improve the convergence of the model. During the calculation process, the external environment temperature and initial temperature are set to 293.15K; the FPC convection heat transfer coefficient is 15W / m 2 K; the initial voltage of FPC is 0 V. Table 1 shows the material properties.
[0034] Table 1
[0035] Serial number name density Conductivity Thermal conductivity 1 Cu 8940[kg / m^3] 5.8e7[S / m] 400[W / (m*K)] 2 PI 1300[kg / m^3] 1e-11[S / m] 0.15[W / (m*K)]
[0036] S4. Meshing the three-dimensional model to obtain a finite element model, wherein the finite element model is a finite element mesh model obtained after meshing the three-dimensional model; meshing is performed using Hypermesh or a meshing module provided by the finite element environment, and in this embodiment, the above two meshing methods are included but not limited to. The meshing sequence is a manually controlled meshing sequence.
[0037] S5, setting a time step transient solver for the finite element model, and performing simulation calculations using an iterative solution method to obtain a simulation result of the finite element model;
[0038] S6. Perform post-processing analysis on the simulation results of the finite element model to obtain the FPC temperature rise results, and determine whether the FPC temperature rise results meet the design requirements. If not, return to step S3; if satisfied, end the calculation and directly output the FPC current value.
[0039] In a preferred embodiment, in step S1, a 3D drawing software is used to establish a 3D model of the FPC, and the established 3D model is exported from the 3D drawing software as a file in ODB++ format, and the 3D drawing software is any one of SolidWorks, CAD, and CATIA. Preferably, in the design of the FPC, the copper thickness of the model geometry is 35um for a single-sided FPC; the upper and lower layer materials are thin film PI media, and, ideally, it is assumed that the glue layer does not affect the actual value.
[0040] In a preferred embodiment, in step S2, the physical parameters include the copper thickness of the FPC circuit, the line width of the FPC circuit, and the temperature rise of the FPC circuit.
[0041] In a preferred embodiment, the copper thickness is (28-42) um, and the temperature rise is (10-40)° C. More preferably, the copper thickness is 35 um.
[0042] In a preferred embodiment, in step S2, the first functional relationship is:
[0043] I max =α*ΔT β *[(1+γ(W-1.0))]
[0044] Among them, I max is the maximum current carrying value within the allowable temperature rise range of FPC, in units of A; ΔT is the allowable temperature rise of FPC, in units of ℃; W is the design line width of FPC, in units of mm; where α is the first judgment constant, β is the first judgment index, and γ is the second judgment index.
[0045] In the simulation environment, the first functional relationship of current carrying capacity is imported by customizing variables to combine the variables. Among them, the variable is line width W, and the independent variable is I max。
[0046] In one embodiment, α is 0.247, β is 0.5, and γ is 1.016. From this expression, it can be seen that the temperature rise and cross-sectional area directly affect the current carrying capacity of the FPC. Through simulation calculations using this expression, the current carrying capacity of the FPC circuit can be preliminarily determined without the need for finished product testing, which shortens the development cycle of FPC products, reduces the manufacturing cost of FPC, and provides a more reliable current carrying and temperature rise calculation method for product development in a finite element simulation environment. It is a reliable and novel method.
[0047] In a preferred embodiment, in step S4, after the three-dimensional model is meshed, the mesh is coarsened to reduce the calculation time of the model and increase the convergence.
[0048] In a preferred embodiment, the post-processing analysis specifically includes:
[0049] S501, processing the simulation result of the FPC three-dimensional model into a transient temperature distribution cloud map of the temperature field;
[0050] S502, inserting a domain point probe into the transient temperature distribution cloud map to monitor the real-time temperature rise dynamics of the FPC before the temperature reaches a steady state, thereby obtaining FPC temperature rise data. The FPC temperature rise data is the FPC temperature rise obtained by post-processing analysis, that is, the FPC temperature rise result.
[0051] After the iterative solver calculates, the model is post-processed with a three-dimensional temperature field to output and draw a transient temperature distribution cloud map. The drawing results are used to determine whether the required results meet the design FPC temperature rise requirements. If yes, the FPC current value is directly output; if not, it indicates that there is an actual error in the set boundary conditions or material parameters, then return to step 3 and perform qualitative analysis based on the actual error until the expected temperature rise value is reached.
[0052] The simulation results of the FPC three-dimensional model are post-processed and analyzed, and it is determined whether the FPC temperature rise results meet the design requirements. After the calculation step of the iterative solver is completed, the model is post-processed using a three-dimensional temperature field, and a transient temperature distribution cloud map is output and drawn. The drawing results are represented to determine whether the required results meet the designed FPC temperature rise condition requirements. If so, the FPC current carrying value under the line width and copper thickness design is directly output; if not, it indicates that there is an actual error in the set boundary conditions or material parameters, that is, return to step S3, and perform qualitative analysis based on the actual error.
[0053] It should be noted that the material properties of actual FPC products will fluctuate between the completion of each process node, and are not the ideal values in the material library. Therefore, those skilled in the art may believe that after the analysis of the post-processing results in step S6, returning to step S3 requires appropriate corrections to the material property parameters and boundary conditions of the model until the expected temperature rise value is reached.
[0054] In a preferred embodiment, the transient solver is any one of a direct solver, an iterative solver, a conjugate gradient solver or a FGMRES solver. The type of solver selected can be calculated by an iterative solution method.
[0055] The difference between direct solvers and iterative solvers is that when the same model involves fewer physical modules, a direct solver can be used to solve it. When the model has more related physical modules, an iterative transient / steady-state solver can be used to solve it, which can avoid the factors of coupling relationships between multiple models, thereby reducing calculation time, accelerating the model to reach a steady state, and improving the convergence of the model.
[0056] It should be noted that the types of solvers can be divided into two major categories, including direct solvers and iterative solvers.
[0057] Among them, direct solvers include MUMPS and PARDISO solvers. Both MUMPS and PARDISO solvers can use all processor cores on a single machine to perform calculations, but the biggest disadvantage of direct solvers is that they both require a huge amount of physical memory, namely RAM. PARDISO solvers can store solutions outside the core, that is, cache the calculation content on other hard disk spaces, which can alleviate the physical memory RAM of the calculation. The difference between direct solvers and iterative solvers is that when the same model involves fewer physical modules, direct solvers can be used to solve it.
[0058] In addition, iterative solvers include conjugate gradient solver, FGMRES solver. In contrast to direct solvers, iterative methods solve the problem step by step instead of computing more intensive steps by consuming more physical RAM.
[0059] It should be noted that the conjugate gradient solver is an iterative solver, which is particularly suitable for solving symmetric positive definite matrices and large-scale linear static modal analysis, but it converges slowly for poorly conditioned matrices. The FGMRES solver can improve the convergence speed and computational efficiency of iterative solutions for large sparse matrices by reducing the condition number of the matrix.
[0060] Then, when the model has many related physical modules, using an iterative transient / steady-state solver to solve the problem can avoid the coupling factors of multiple models, thereby reducing the calculation time, accelerating the model to reach a steady state, and improving the convergence of the model.
[0061] In this embodiment, in order to achieve a fast-converging physical field model, the FGMRES iterative solver is selected for solving.
[0062] In the absence of finished product testing, the current carrying capacity of the FPC circuit can be preliminarily determined, which shortens the development cycle of FPC products, reduces the manufacturing cost of FPC, and provides a more reliable current carrying and temperature rise calculation method for product development under the finite element simulation environment. It is a reliable and novel method. In the present invention, FPC refers to a flexible circuit board.
[0063] The present invention provides a storage medium on which a computer program is stored, characterized in that the computer program runs the method described when executed by a processor.
[0064] like Figure 2As shown, an electronic device includes a processor and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the method described above is executed. Preferably, the electronic device is a computer operating device, and a schematic diagram of the internal composition of the computer operating device. The computer operating device can connect each module in series through a bus, and the specific modules may include but are not limited to a readable RAM, a storable ROM, an input interface, a GPU, a program / operating system, a finite element environment, a display terminal, and a multi-threaded central processing unit. The computer operating device can operate and calculate the FPC current carrying value in an environment that satisfies the executable finite element.
[0065] The computer operating device is Figure 2 It is shown that only one embodiment is described in this embodiment and is not limited to the use and protection of other computer operating devices.
[0066] In a preferred embodiment, the readable RAM of the computer operating device may be a dynamic low frequency 1600MHz RAM or a high frequency 3200MHz RAM. The storable ROM may be a programmable ROM (PROM), an electrically programmable ROM (EPROM) or a read-only ROM. The input interface of the computer operating device may be a matrix input keyboard, a movable mouse device, a control touch panel, or a combination of one or more devices. The GPU of the computer operating device may include an integrated mode GPU, an independent high bandwidth GPU capable of parallel computing, an independent GPU capable of high-speed floating-point computing, etc., including but not limited to one type thereof.
[0067] In a preferred embodiment, by Figure 2 It can be seen that the program / operating system of the computer operating device may include one of Windows, Linux, DOS, UNIX, and Mac OS.
[0068] Those skilled in the art may believe that the operating system and program in the preferred embodiment of the computer operating device are only described in one embodiment of the present invention, and are not limited to one computer operating system or multiple systems used in parallel. The present embodiment can be implemented by one or more electronic devices of micro-electromechanical devices, embedded Linux operating devices, and Windows operating devices that can execute command lines, Shell and other scripts. All schemes in the present embodiment can use a variety of machine languages to write scripts, such as Python, C / C++, Java, etc. The results of the script schemes run through the finite element environment are not limited to the results of the embodiments of the present invention, and the results generated meet all the principles required by the cases of the present invention.
[0069] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. A calculation method for a finite element model of FPC current carrying capacity, an electronic device and a storage medium, characterized in that: The steps include: S1. Establish a three-dimensional model of FPC; S2, establishing a first functional relationship corresponding to the FPC current carrying capacity model, and setting physical parameters that affect the FPC current carrying capacity; S3, setting physical field parameters and establishing boundary conditions; S4, meshing the three-dimensional model to obtain a finite element model; S5, setting a time step transient solver for the finite element model, and performing simulation calculations using an iterative solution method to obtain a simulation result of the finite element model; S6, performing post-processing analysis on the simulation results of the finite element model to obtain the FPC temperature rise results, and judging whether the FPC temperature rise results meet the design requirements, if not, returning to step S3; If satisfied, the calculation ends and the FPC current carrying value is directly output.
2. The method according to claim 1, characterized in that In step S1, a three-dimensional model of the FPC is established using 3D drawing software, and the established three-dimensional model is exported from the 3D drawing software as a file in ODB++ format. The 3D drawing software is any one of Solid Works, CAD, and CATIA.
3. The method according to claim 1, characterized in that In step S2, the physical parameters include the copper thickness of the FPC circuit, the line width of the FPC circuit, and the temperature rise of the FPC circuit.
4. The method according to claim 3, characterized in that In step S2, the first functional relationship is: I max =α*ΔT β *[(1+γ(W-1.0))] Among them, I max is the maximum current carrying value within the allowable temperature rise range of FPC, in units of A; ΔT is the allowable temperature rise of FPC, in units of ℃; W is the design line width of FPC, in units of mm; where α is the first judgment constant, β is the first judgment index, and γ is the second judgment index.
5. The method according to claim 4, characterized in that The copper thickness is (28-42) um and the temperature rise is (10-40)°C.
6. The system according to claim 1, wherein: In step S4, after the three-dimensional model is meshed, the mesh division is coarsened.
7. The method according to claim 1, characterized in that The post-processing analysis specifically includes: S501, processing the simulation result of the FPC three-dimensional model into a transient temperature distribution cloud map of the temperature field; S502, inserting a domain point probe into the transient temperature distribution cloud map to monitor the real-time temperature rise dynamics of the FPC before the temperature reaches a steady state, thereby obtaining FPC temperature rise data.
8. The method according to claim 1, characterized in that The transient solver is any one of a direct solver, an iterative solver, a conjugate gradient solver or a FGMRES solver.
9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 8 is executed.
10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is executed.