Entity structure load spectrum durability damage calculation method, system, device and storage medium

Abstract

The application discloses a solid structure load spectrum durability damage calculation method, system, equipment and storage medium, belongs to the automobile technical field, and specifically includes the following steps: adopting a first-order tetrahedral element to carry out mesh division on the solid structure; a second-order tetrahedral and a plate shell element material and section attribute are established and given; the mass of the solid structure under the conditions of having and not having a surface plate shell element is calculated respectively, and whether the mass deviation value of the two meets the requirements is judged; the stiffness and structure stress of the solid structure connecting point under the conditions of having and not having a surface plate shell element are calculated respectively, and whether the deviation value meets the requirements is judged; the unit load stress of the solid structure with the surface generated plate shell element is calculated; and the surface plate shell element fatigue damage is calculated based on the load spectrum. The method equivalently reduces a simulation model of the order of millions to the order of ten thousand or less, shortens the simulation time from 160 hours to 8 hours or less, and improves the efficiency by 95%.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, specifically relating to a method, system, device, and storage medium for calculating durability damage of solid structures under load spectrum. Background Technology

[0002] In the traditional automotive strength and durability development process, the load spectrum durability damage value of the load-bearing structure must meet the evaluation indicators specified by the company. Generally speaking, the load spectrum durability damage value of an automotive structure is a synthesis of damage from different bad roads in the test track. Bad roads in the test track include 15-30 types, such as railway tracks, potholes, and cobblestone roads. The types of bad roads included in different test tracks vary slightly, and different automakers also use slightly different methods to handle the load spectrum. Based on the principle of damage equivalence, the load spectrum ultimately used for structural durability damage calculation is generally composed of 10-20 types of bad road spectra.

[0003] For solid structures such as cast aluminum subframes and steering knuckles, accurately calculating structural stress under various load conditions typically requires meshing with a thickness of 1-2 mm. This results in simulation models with millions of elements or nodes. When performing fatigue damage calculations based on load spectra using simulation models of this scale, the computational efficiency is extremely low due to the excessive number of nodes. If a test track specification includes 20 types of road surfaces, each with its own RSP load spectrum file, calculating the durability damage of a single load spectrum for a structure with millions of nodes would take approximately 8 hours. For 20 road surfaces, this would require 160 hours, which is unacceptable in product development. Summary of the Invention

[0004] To address the problem of low efficiency in calculating structural stress of solid structures under various load conditions in existing technologies, this invention proposes a method, system, equipment, and storage medium for calculating durability damage of solid structures under load spectrum. This method reduces the simulation model from millions to less than tens of thousands, shortens the simulation time from 160 hours to less than 8 hours, and improves efficiency by 95%.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for calculating the durability damage of a solid structure under load spectrum, specifically including the following steps:

[0007] S1: Mesh the solid structure using first-order tetrahedral elements;

[0008] S2: Establish and assign material and section properties to second-order tetrahedral and plate / shell elements;

[0009] S3: Calculate the mass of the solid structure with and without surface shell elements, and determine whether it meets the requirements based on the mass deviation between the two cases; if it does, proceed to the next step.

[0010] S4: Calculate the stiffness and structural stress at the connection points of the solid structure with and without surface shell elements, and determine whether the deviation values ​​meet the requirements; if they do, proceed to the next step.

[0011] S5: Calculate the unit load stress of the solid structure of the surface-generated plate and shell unit;

[0012] S6: Calculate fatigue damage of surface plate and shell elements based on load spectrum.

[0013] Further, in step S1, nodes are inserted into the first-order tetrahedral element to transform it into a second-order tetrahedral element, and a 0.01mm thick shell element is generated on the surface of the second-order tetrahedral element.

[0014] Furthermore, the shell unit is a triangular shell unit.

[0015] Furthermore, in step S3, if the mass deviation between the two is less than 2%, it meets the requirements; if the mass deviation between the two is greater than or equal to 2%, it does not meet the requirements, and the thickness attribute of the shell unit is readjusted until it meets the requirements.

[0016] Furthermore, in step S4, if the deviation between the stiffness and structural stress of the connection point of the solid structure obtained from the two calculations is less than 2%, then it meets the requirements; if the deviation obtained from the two calculations is greater than or equal to 2%, then it does not meet the requirements, and the thickness attribute of the plate and shell unit is readjusted until it meets the requirements.

[0017] Furthermore, in step S5, the unit load stress of the solid structure of the surface-generated plate-shell element is calculated using ABAQUS.

[0018] Furthermore, in step S6, fatigue damage of the surface plate and shell elements is directly calculated using FEMFAT software based on the load spectrum.

[0019] Secondly, the present invention also provides a system for calculating the durability damage of a solid structure under load spectrum, for implementing the above method, including:

[0020] The mesh generation module is used to mesh solid structures using first-order tetrahedral elements.

[0021] The module is used to create and assign material and section properties to second-order tetrahedral and plate / shell elements;

[0022] The first calculation module is used to calculate the mass of the solid structure with and without surface shell elements, and to determine whether the mass deviation between the two meets the requirements; if it does, proceed to the next step.

[0023] The second calculation module is used to calculate the stiffness and structural stress of the connection points of the solid structure with and without surface shell elements, and to determine whether the deviation value meets the requirements; if it does, proceed to the next step.

[0024] The third calculation module is used to calculate the unit load stress of the solid structure of the surface-generated plate and shell unit;

[0025] The fourth calculation module is used to calculate the fatigue damage of the surface plate and shell elements based on the load spectrum.

[0026] Thirdly, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for calculating the durability damage of a solid structure under load spectrum as described in any one of the present invention.

[0027] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for calculating the durability damage of a solid structure under load spectrum as described in any one of the present invention.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] The present invention provides a method for calculating the durability damage of solid structures by generating triangular plate shell elements on the surface of the solid structure, thereby reducing the simulation scale. This method can reduce the simulation model of millions to less than tens of thousands, shorten the simulation time from 160 hours to less than 8 hours, and improve the efficiency by 95%. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0031] Figure 1 This is a flowchart illustrating a method for calculating the durability damage of a solid structure under load spectrum according to the present invention.

[0032] Figure 2 This is a schematic diagram of a second-order tetrahedral solid subframe structure;

[0033] Figure 3 This is a schematic diagram of a first-order triangular plate shell unit subframe structure;

[0034] Figure 4 This is a schematic diagram of the structure of an electronic device according to Embodiment 3 of the present invention. Detailed Implementation

[0035] To clearly and completely describe the technical solution and its specific working process of the present invention, the specific embodiments of the present invention are as follows, in conjunction with the accompanying drawings:

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0039] Example 1

[0040] This embodiment takes a cast aluminum subframe structure as an example. First, a first-order tetrahedral element is used to mesh the solid subframe structure. To obtain accurate stress simulation results, the first-order tetrahedral element is converted into a second-order tetrahedral element. A 0.01mm thick shell element is generated on the surface of the second-order tetrahedral element. After assigning cross-sectional properties to the second-order tetrahedral element and the shell element, the mass of the subframe solid structure with and without the shell element is calculated. The mass deviation cannot exceed 2%. The stiffness and stress at the connection points of the subframe with and without the shell element are calculated separately. The stiffness deviation and stress deviation at the connection points cannot exceed 2%. After all conditions are met, the stress of the subframe structure with the shell element is calculated. Combined with the hard point load spectrum, the durability damage of the surface element is directly calculated in the FEMFAT software. The flowchart of the durability damage calculation for the load spectrum of the solid structure is shown below. Figure 1 As shown; specifically, it includes the following detailed steps:

[0041] The first step is to mesh the solid subframe structure using first-order tetrahedral elements. To obtain accurate stress distribution, the first-order tetrahedral elements need to be converted into second-order tetrahedral elements, such as... Figure 2 As shown;

[0042] The second step is to generate triangular plate shell elements on the surface of the second-order tetrahedral elements, such as... Figure 3 As shown;

[0043] The third step is to establish the material and section properties of the second-order tetrahedral solid element and the triangular plate shell element. The initial thickness of the plate shell element is 0.01mm, and the corresponding structures are assigned to them respectively.

[0044] The fourth step is to calculate the mass of the structure with and without surface triangular plate shell elements. The mass deviation between the two cases should be less than 2%. If the requirement is not met, the thickness attribute of the plate shell element needs to be adjusted.

[0045] The fifth step is to calculate the connection point stiffness and structural stress with and without surface triangular plate shell elements. The deviation of both should be controlled within 2%. If the requirements are not met, the thickness attribute of the plate shell element needs to be further reduced.

[0046] The sixth step is to adjust the thickness properties of the shell elements to achieve the effect of the stress of the second-order tetrahedral element being consistent with the stress of the triangular shell elements on its surface.

[0047] Step 7: Use ABAQUS to calculate the unit load stress of the subframe solid structure with surface triangular plate shell elements, and obtain the odb stress results;

[0048] Step 8: Since the stress of the shell elements and the solid elements is consistent, and the number of nodes and elements is much smaller, the FEMFAT software is used to directly read the stress of the triangular shell elements in the odb results to calculate the fatigue damage of the solid subframe structure, based on the load spectrum of the connection points.

[0049] Example 2

[0050] This embodiment provides a load spectrum durability damage calculation system for solid structures, used to implement the method described in Embodiment 1, including:

[0051] The mesh generation module is used to mesh solid structures using first-order tetrahedral elements.

[0052] The module is used to create and assign material and section properties to second-order tetrahedral and plate / shell elements;

[0053] The first calculation module is used to calculate the mass of the solid structure with and without surface shell elements, and to determine whether the mass deviation between the two meets the requirements; if it does, proceed to the next step.

[0054] The second calculation module is used to calculate the stiffness and structural stress of the connection points of the solid structure with and without surface shell elements, and to determine whether the deviation value meets the requirements; if it does, proceed to the next step.

[0055] The third calculation module is used to calculate the unit load stress of the solid structure of the surface-generated plate and shell unit;

[0056] The fourth calculation module is used to calculate the fatigue damage of the surface plate and shell elements based on the load spectrum.

[0057] Example 3

[0058] Figure 4 This is a schematic diagram of the structure of a computer device in Embodiment 3 of the present invention. Figure 4 A block diagram of an exemplary computer device 12 suitable for implementing embodiments of the present invention is shown. Figure 4 The computer device 12 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.

[0059] like Figure 4 As shown, the computer device 12 is represented in the form of a general-purpose computing device. The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, system memory 28, and a bus 18 connecting different system components (including system memory 28 and processing unit 16).

[0060] Bus 18 represents one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. For example, these architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI) bus.

[0061] Computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0062] System memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, storage system 34 may be used to read and write non-removable, non-volatile magnetic media (…). Figure 4 Not shown; usually referred to as a "hard drive"). Although Figure 4 Not shown, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk") and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments of the present invention.

[0063] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in memory 28. Such program modules 42 include—but are not limited to—an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment. Program modules 42 typically perform the functions and / or methods described in the embodiments of the present invention.

[0064] The computer device 12 can also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), and with one or more devices that enable a user to interact with the computer device 12, and / or with any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., network card, modem, etc.). This communication can be performed via the input / output (I / O) interface 22. Furthermore, in this embodiment, the display 24 of the computer device 12 is not an independent entity, but is embedded in a mirror, so that when the display surface of the display 24 is not displayed, the display surface of the display 24 and the mirror surface visually blend together. Moreover, the computer device 12 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via the network adapter 20. As shown, the network adapter 20 communicates with other modules of the computer device 12 via the bus 18. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with computer device 12, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0065] The processing unit 16 executes various functional applications and data processing by running programs stored in the system memory 28, such as implementing the solid structure load spectrum durability damage calculation method provided in the embodiments of the present invention.

[0066] Example 4

[0067] Embodiment 4 of the present invention provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method for calculating the durability damage of a solid structure under load spectrum as provided in all embodiments of the present application.

[0068] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0069] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of transmitting, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0070] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0071] Computer program code for performing the operations of this invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0072] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for calculating durability damage of solid structures under load spectrum, characterized in that, Specifically, the steps include the following: S1: Mesh the solid structure using first-order tetrahedral elements; S2: Establish and assign material and section properties to second-order tetrahedral and plate / shell elements; S3: Calculate the mass of the solid structure with and without surface shell elements, and determine whether it meets the requirements based on the mass deviation between the two. If it meets the requirements, proceed to the next step; S4: Calculate the stiffness and structural stress at the connection points of the solid structure with and without surface shell elements, and determine whether the requirements are met based on the deviation values. If it meets the requirements, proceed to the next step; S5: Calculate the unit load stress of the solid structure of the surface-generated plate and shell unit; S6: Calculate fatigue damage of surface plate and shell elements based on load spectrum; In step S1, nodes are inserted into the first-order tetrahedral element to transform it into a second-order tetrahedral element, and a 0.01mm thick shell element is generated on the surface of the second-order tetrahedral element. In step S3, if the mass deviation between the two is less than 2%, it meets the requirements; if the mass deviation between the two is greater than or equal to 2%, it does not meet the requirements. Then, the thickness attribute of the shell unit is readjusted until it meets the requirements. In step S4, if the deviation between the stiffness and structural stress of the connection point of the solid structure obtained from the two calculations is less than 2%, it meets the requirements. If the deviation obtained from the two calculations is greater than or equal to 2%, it does not meet the requirements. Then, the thickness attribute of the plate and shell unit is readjusted until it meets the requirements.

2. The method for calculating the durability damage of a solid structure under load spectrum as described in claim 1, characterized in that, The shell unit is a triangular shell unit.

3. The method for calculating the durability damage of a solid structure under load spectrum as described in claim 1, characterized in that, In step S5, the unit load stress of the solid structure of the surface-generated plate and shell elements is calculated using ABAQUS.

4. The method for calculating the durability damage of a solid structure under load spectrum as described in claim 1, characterized in that, In step S6, fatigue damage of the surface plate and shell elements is directly calculated using FEMFAT software based on the load spectrum.

5. A system for calculating the durability damage of a solid structure under load spectrum, used in accordance with the calculation method described in any one of claims 1-4, characterized in that, include: The mesh generation module is used to mesh solid structures using first-order tetrahedral elements. The module is used to create and assign material and section properties to second-order tetrahedral and plate / shell elements; The first calculation module is used to calculate the mass of the solid structure with and without surface shell elements, and to determine whether it meets the requirements based on the mass deviation between the two. If it meets the requirements, proceed to the next step; The second calculation module is used to calculate the stiffness and structural stress of the connection points of the solid structure with and without surface plate shell elements, and to determine whether the requirements are met based on the deviation value. If it meets the requirements, proceed to the next step; The third calculation module is used to calculate the unit load stress of the solid structure of the surface-generated plate and shell unit; The fourth calculation module is used to calculate the fatigue damage of the surface plate and shell elements based on the load spectrum.

6. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for calculating the durability damage of a solid structure under load spectrum as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the method for calculating the durability damage of a solid structure under load spectrum as described in any one of claims 1-4.

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