A method and system for predicting fatigue life of a mounting bolt of an automobile fuel gas tank and a storage medium

Abstract

The application relates to the technical field of mechanical engineering, and discloses a method and system for predicting the fatigue life of a mounting bolt of a fuel gas tank of an automobile and a storage medium, wherein the method comprises the following steps: constructing a finite element model of the fuel gas tank system; obtaining a random vibration spectrum of the fuel gas tank under the condition that the warranty life of the whole vehicle is associated with the test field road test specification of the whole vehicle; based on rain flow statistical analysis, equivalently converting the random vibration spectrum into load cycles to obtain a block vibration spectrum; if the deviation between the pseudo-damage value of the block vibration spectrum and the pseudo-damage value of the random vibration spectrum is within a set threshold, loading the block vibration spectrum in the finite element model to extract a mounting bolt load parameter; and based on the mounting bolt load parameter, predicting the fatigue life of the bolt, so that the technical problem of predicting the fatigue life of the mounting bolt of the fuel gas tank is solved, and the technical effect of effectively controlling the bolt fastening performance and cost is achieved.

Description

Technical Field

[0001] The present application relates to the field of mechanical engineering technology, and in particular to a method, system and storage medium for predicting fatigue life of automobile fuel tank mounting bolts. Background Art

[0002] Fuel tank trucks are commonly used to transport various types of fuel gas, including LNG (liquefied natural gas), CNG (compressed natural gas), and LPG (liquefied petroleum gas). Currently, fuel tanks are primarily bolted to the vehicle's frame. When the vehicle traverses uneven terrain during transportation, the load on the tires is transmitted through the frame to the fuel tank, causing it to vibrate violently. Reliable bolt tightening prevents the tank from sliding and falling, and predicting the fatigue life of the bolts is crucial for fuel tank system design. Summary of the Invention

[0003] The present application provides a method, system and storage medium for predicting the fatigue life of automobile fuel tank mounting bolts, which solves the technical problem of predicting the fatigue life of fuel tank mounting bolts and achieves the technical effect of effectively controlling the bolt tightening performance and cost.

[0004] In order to achieve the above objectives, the main technical solutions adopted in this application include:

[0005] In a first aspect, an embodiment of the present application provides a method for predicting the fatigue life of automobile fuel tank mounting bolts, the method comprising: constructing a finite element model of the fuel tank system; obtaining a random vibration spectrum of the fuel tank when the vehicle warranty life is associated with the vehicle test field road test specifications; based on rain flow statistical analysis, converting the random vibration spectrum into an equivalent load cycle to obtain a block vibration spectrum; if the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, loading the block vibration spectrum into the finite element model and extracting the mounting bolt load parameters; based on the mounting bolt load parameters, predicting the fatigue life of the bolt.

[0006] The fatigue life prediction method of automobile fuel tank mounting bolts proposed in the embodiment of the present application constructs a finite element model of the fuel tank system, obtains the random vibration spectrum of the fuel tank when the warranty life of the whole vehicle is associated with the road test specifications of the whole vehicle test field, and converts the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum. If the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model, and the mounting bolt load parameters are extracted. Based on the mounting bolt load parameters, the fatigue life of the bolts is predicted, which solves the technical problem of fatigue life prediction of automobile fuel tank mounting bolts and achieves the technical effect of effectively controlling the bolt tightening performance and cost.

[0007] Optionally, the vehicle warranty life is associated with the vehicle proving ground road test specifications, and is used to indicate that a first road surface stimulus received by the vehicle in the proving ground is equivalent to a second road surface stimulus received within the warranty life.

[0008] Optionally, the mounting bolt load parameters include a load value of the mounting bolt and a cycle number of a block vibration spectrum.

[0009] Optionally, constructing the finite element model of the fuel gas tank system specifically includes: constructing a discretized grid based on the digital model of each component of the fuel gas tank system; obtaining the weight and center of mass of each component of the fuel gas tank system, and performing model weighting on the discretized grid; if the discretized grid after the model weighting meets the consistency standard with the weight and center of mass of the actual components, then based on the discretized grid after the model weighting, setting simulated welds, simulated contacts, simulated bolt pre-tightening and bolt loading units to obtain the finite element model of the fuel gas tank system.

[0010] Optionally, if the discretized grid after weighting the model does not meet the consistency standard with the weight and center of mass of the actual component, the cell density of the discretized grid is reset to adjust the weight and center of mass of the discretized grid.

[0011] Optionally, the step of loading the block vibration spectrum into the finite element model and extracting the mounting bolt load parameters specifically includes: obtaining the load value of the mounting bolt by calculating the vector displacement of any point in the bolt loading unit.

[0012] Optionally, the bolt load-carrying unit includes a first node, a second node, and a third node connected in sequence, wherein the first node is used to couple one end of the bolt connection, and the third node is used to couple the other end of the bolt connection, and the unit shape functions of the first node, the second node, and the third node are respectively:

[0013]

[0014] In the above formula, ν is a random number between -1 and 1; N1, N2, and N3 are the element shape functions of the first, second, and third nodes, respectively;

[0015] The vector displacement of any point in the bolt load-carrying unit is:

[0016] δ i =N1·δ1+N2·δ2+N3·δ3

[0017] In the above formula, δ i is the vector displacement of any point in the bolt load-bearing unit, δ1 is the vector displacement of the first node, δ2 is the vector displacement of the second node, and δ3 is the vector displacement of the third node.

[0018] Among them, the introduction of the second node enables the entire bolt load-bearing unit to bend and torsionally deform, which is conducive to the high-precision extraction of torsional loads. By calculating the vector displacement of any point in the bolt load-bearing unit, the load value of the bolt load-bearing unit can be obtained when the bolt stiffness is known.

[0019] Optionally, based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum, specifically including: based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain the load amplitude and number of cycles of the load cycle; based on the load amplitude and number of cycles of the load cycle, a block vibration spectrum is constructed.

[0020] Optionally, the warranty period of the vehicle is 10 years and the mileage is 200,000 kilometers.

[0021] Optionally, the fuel gas tank system is a CNG gas tank system.

[0022] In a second aspect, an embodiment of the present application provides a fatigue life prediction system for automobile fuel tank mounting bolts, the system comprising: a finite element model construction module for constructing a finite element model of the fuel tank system; a block vibration spectrum construction module for obtaining the random vibration spectrum of the fuel tank when the whole vehicle warranty life is associated with the whole vehicle test field road test specifications; and a module for converting the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum; a bolt fatigue prediction module for predicting the fatigue life of the bolt according to the mounting bolt load parameters, wherein if the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model to extract the mounting bolt load parameters.

[0023] In a third aspect, an embodiment of the present application provides a computer device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, computer instructions are stored in the memory, and the processor executes the above method by executing the computer instructions.

[0024] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which computer instructions are stored, and the computer instructions are used to enable a computer to execute the above method.

[0025] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising computer instructions, which are used to enable a computer to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] Figure 1 A flowchart of a method for predicting fatigue life of automobile fuel tank mounting bolts provided in an embodiment of the present application;

[0028] Figure 2 A flowchart of a method for constructing a finite element model of a fuel tank system provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of a finite element model of a CNG gas tank system provided in an embodiment of the present application;

[0030] Figure 4 A flowchart of a method for predicting fatigue life of mounting bolts of a CNG gas tank system provided in an embodiment of the present application;

[0031] Figure 5 A schematic diagram of a fatigue life prediction system for mounting bolts of an automobile fuel tank is provided for an embodiment of the present application;

[0032] Figure 6 A schematic diagram of the structure of a computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0034] Fuel tank trucks are commonly used to transport various types of fuel gas, including LNG (liquefied natural gas), CNG (compressed natural gas), and LPG (liquefied petroleum gas). Currently, fuel tanks are primarily bolted to the vehicle's frame. When the vehicle traverses uneven terrain during transportation, the load on the tires is transmitted through the frame to the fuel tank, causing it to vibrate violently. Reliable bolt tightening prevents the tank from sliding and falling, and predicting the fatigue life of the bolts is crucial for fuel tank system design.

[0035] Fuel tank vehicles operate under complex operating conditions. Accurately obtaining the random vibration load spectrum of fuel tanks is fundamental to predicting the fatigue life of mounting bolts, yet also presents a significant challenge. Fuel tanks are assembled using multiple bolts, requiring accurate decomposition of the random vibration load spectrum down to the hard points of the multiple bolt connections to determine the vibration loads on these bolts. This is currently unavailable in related technologies.

[0036] An embodiment of the present application provides an embodiment of a method for predicting the fatigue life of automobile fuel tank mounting bolts. By setting up a simulation environment, a finite element model of the fuel tank system is constructed in the simulation environment, the vehicle road test specifications are associated with the vehicle warranty life, and the measured random vibration spectrum of the fuel tank is obtained in the test field. Through rain flow statistical analysis, rain flow statistical results are obtained. Based on the rain flow statistical results, a block vibration spectrum is obtained. If the first pseudo-damage value of the block vibration spectrum is equal to the second pseudo-damage value of the random vibration spectrum, the block vibration spectrum is loaded into the finite element model to obtain the mounting bolt load parameters. Based on the mounting bolt load parameters, the fatigue life of the mounting bolt is predicted.

[0037] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Please refer to Figure 1 , Figure 1 This is a flow chart of a method for predicting fatigue life of automobile fuel tank mounting bolts provided in an embodiment of the present application, such as Figure 1 As shown, the process includes the following steps:

[0039] Step S1, constructing a finite element model of the fuel tank system.

[0040] In fuel tank systems, after bolts are installed, the internal loads cannot be directly measured. Finite element models discretize continuous physical systems into a finite number of small units, allowing for accurate numerical simulation of complex systems. By constructing a finite element model of a fuel tank system, numerical simulation and analysis of a physical prototype (i.e., the actual fuel tank system) can be performed, reducing reliance on physical prototypes and reducing costs and development time.

[0041] In some embodiments, a finite element model of the fuel tank system may be constructed using abaqus simulation software.

[0042] Step S3: obtaining a random vibration spectrum of the fuel tank when the vehicle warranty life is associated with the vehicle proving ground road test specification.

[0043] Among them, vehicle proving ground road test specifications are a series of testing standards and procedures developed to ensure the performance, safety, and reliability of the vehicle under actual road conditions. These specifications typically include tests on the vehicle's power, braking, handling stability, environmental performance, comfort, and durability. The vehicle warranty life typically refers to a quality assurance commitment for the vehicle's overall quality over a certain period of time and mileage. The vehicle warranty life can be expressed in terms of time or mileage, whichever comes first.

[0044] In order to obtain test data for the entire vehicle within its warranty life, the time and cost usually required are too high. This can be obtained through equivalent incentives. The warranty life of the entire vehicle is associated with the road test specifications of the vehicle proving ground, which is used to indicate that the first road incentive received by the entire vehicle in the proving ground is equivalent to the second road incentive received within the warranty life. The first road surface refers to the ordinary road surface on which users drive, and the second road surface refers to the proving ground road surface. In order to obtain test data for the entire vehicle within its warranty life, equivalent incentives can be applied to the entire vehicle on the proving ground road surface, thereby greatly reducing testing time and costs. For example, in order to obtain performance test data within 10 years or 200,000 kilometers of the warranty life of the entire vehicle, equivalent incentives can be applied to the entire vehicle at the proving ground based on equivalent incentives, and the performance test data obtained by driving the entire vehicle for 3 months at the proving ground will be regarded as the performance test data of the entire vehicle within its warranty life.

[0045] For example, to obtain the random vibration spectrum of a vehicle within its warranty life, the warranty life can be linked to the road test specifications of the vehicle proving ground. This allows for the acquisition of test data equivalent to the warranty life in a shorter time at the proving ground, resulting in an equivalent random vibration spectrum. The random vibration spectrum characterizes the excitation transfer from the road surface to the tires and fuel tanks.

[0046] Specifically, multiple acceleration sensors are attached to the fuel gas tank, and a random vibration spectrum equivalent to the warranty life can be obtained by testing in a test field.

[0047] In step S5, based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum.

[0048] Random vibration spectra typically contain a large number of data points, making direct analysis of these data very complex. Rainflow statistical analysis can be used to convert random vibration spectra into block-based vibration spectra, simplifying the complex random vibration into a series of cyclic blocks, each with a well-defined amplitude and number of cycles. This simplifies the analysis process and better simulates actual loading conditions, facilitating fatigue life analysis.

[0049] The parameters of the block vibration spectrum include the block vibration spectrum amplitude and the number of cycles of the block vibration spectrum.

[0050] Step S7: If the deviation between the first pseudo damage value of the block vibration spectrum and the second pseudo damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model to extract the installation bolt load parameters.

[0051] The formula for calculating the pseudo damage value is:

[0052] N=αS -β

[0053] In the above formula, S is the stress amplitude; N is the pseudo damage value of the specimen under the action of stress amplitude S; α is a constant; β is the fatigue strength index.

[0054] If the deviation between the first pseudo damage value of the block vibration spectrum and the second pseudo damage value of the random vibration spectrum is within a set threshold, it indicates that the damage effects of the random vibration spectrum and the block vibration spectrum are equivalent.

[0055] For example, in Abaqus simulation software, the block vibration spectrum can be loaded into the finite element model using modal superposition or direct time history analysis. The simulation software is then run to calculate the mounting bolt's response to the block vibration spectrum, including displacement, to determine the bolt load parameters. These parameters include the bolt load value and the number of cycles in the block vibration spectrum. Given a known bolt stiffness, the bolt load value can be determined by calculating the bolt displacement.

[0056] Step S9: predicting the fatigue life of the bolt based on the installation bolt load parameters.

[0057] The bolt load parameters include the maximum load value, minimum load value, and the number of cycles of the block vibration spectrum. These parameters are then input into the bolt fatigue life prediction software to perform fatigue life prediction analysis, calculate the bolt safety factor, and predict the bolt fatigue life.

[0058] The fatigue life prediction method for automobile fuel tank mounting bolts provided in this embodiment constructs a finite element model of the fuel tank system, obtains the random vibration spectrum of the fuel tank when the warranty life of the vehicle is associated with the road test specifications of the vehicle test field, and converts the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum. If the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model, the mounting bolt load parameters are extracted, and the fatigue life of the bolts is predicted based on the mounting bolt load parameters, thereby solving the technical problem of fatigue life prediction of automobile fuel tank mounting bolts and achieving the technical effect of effectively controlling the bolt tightening performance and cost.

[0059] In some embodiments, a discretized grid is constructed based on the digital model of each component of the fuel gas tank system; the weight and center of mass of each component of the fuel gas tank system are obtained, and the discretized grid is weighted; if the discretized grid after the model weighting meets the consistency standard with the weight and center of mass of the actual components, then based on the discretized grid after the model weighting, simulated welds, simulated contacts, simulated bolt pre-tightening and bolt loading units are set to obtain a finite element model of the fuel gas tank system.

[0060] Among them, the consistency standard means that the deviation between the discretized grid after the model is weighted and the weight and center of mass of the actual components of the fuel tank system is within the allowable error range, ensuring that the numerical simulation calculation results of the finite element model are consistent with the actual situation.

[0061] Please refer to Figure 2 , Figure 2 A flowchart of a method for constructing a finite element model of a fuel gas tank system provided in an embodiment of the present application specifically includes: constructing a discretized grid based on the digital model of each component, including setting the cell density of the discretized grid; weighting the discretized grid to simulate the load that the prototype may bear in actual use; judging whether the weight and center of mass of the discretized grid after model weighting meet the consistency standard with the weight and center of mass of the actual components; if not, readjusting the cell density of the discretized grid, thereby adjusting the weight and center of mass of the discretized grid until the consistency standard is met; if so, setting simulated welds, simulated contacts, simulated bolt pre-tightening and bolt load-bearing units based on the discretized grid after weighting to obtain a finite element model of the fuel gas tank system.

[0062] In the simulation software, coupling is performed by setting coupling points between two connecting parts to simulate welds; contact is simulated by defining the modal coefficients between the master and slave contact surfaces; bolt pre-tightening is simulated by simulating the clamping force between the bolt and the nut by loading a load on the bolt; and three node units are set on the bolt, where the node units at both ends are coupled with the connecting parts and the node unit in the middle is set as a bolt load-bearing unit.

[0063] In some embodiments, the bolt load-carrying unit includes a first node, a second node, and a third node connected in sequence, wherein the first node is used to couple one end of the bolt connection, and the third node is used to couple the other end of the bolt connection. The unit shape functions of the first node, the second node, and the third node are respectively:

[0064]

[0065] In the above formula, ν is a random number between -1 and 1; N1, N2, and N3 are the element shape functions of the first, second, and third nodes, respectively;

[0066] The vector displacement of any point in the bolt load-bearing unit is:

[0067] δ i =N1·δ1+N2·δ2+N3·δ3

[0068] In the above formula, δ i is the vector displacement of any point in the bolt load-bearing unit, δ1 is the vector displacement of the first node, δ2 is the vector displacement of the second node, and δ3 is the vector displacement of the third node.

[0069] Among them, the introduction of the second node enables the entire bolt load-bearing unit to bend and torsionally deform, which is conducive to the high-precision extraction of torsional loads. By calculating the vector displacement of any point in the bolt load-bearing unit, the load value of the bolt load-bearing unit can be obtained when the bolt stiffness is known.

[0070] In some embodiments, based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum, specifically including: based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain the load amplitude and number of cycles of the load cycle; based on the load amplitude and number of cycles of the load cycle, a block vibration spectrum is constructed.

[0071] In some embodiments, the fuel gas tank system is a CNG gas tank system, please refer to Figure 3 , Figure 3 This is a schematic diagram of the finite element model of the CNG gas tank system provided in the embodiment of this application. Please refer to Figure 4 , Figure 4 A flowchart of a method for predicting the fatigue life of mounting bolts of a CNG gas tank system provided in an embodiment of the present application. By constructing a finite element model of the CNG gas tank system, the random vibration spectrum of the CNG gas tank is obtained under the condition that the vehicle warranty life of 10 years and 200,000 kilometers is associated with the road test specifications of the vehicle test field. Based on rain flow statistical analysis, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum. If the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model of the CNG gas tank system, the mounting bolt load parameters are extracted, and the fatigue life of the bolts is predicted based on the mounting bolt load parameters. This solves the technical problem of fatigue life prediction of mounting bolts of automobile fuel tanks and achieves the technical effect of effectively controlling the tightening performance and cost of the bolts.

[0072] Please refer to Figure 5 , Figure 5A schematic diagram of a fatigue life prediction system for automobile fuel tank mounting bolts is provided for an embodiment of the present application. The fatigue life prediction system for automobile fuel tank mounting bolts includes: a finite element model construction module for constructing a finite element model of the fuel tank system; a block vibration spectrum construction module for obtaining the random vibration spectrum of the fuel tank when the whole vehicle warranty life is associated with the whole vehicle test field road test specifications; and a bolt fatigue prediction module for converting the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum; wherein, if the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model to extract the mounting bolt load parameters.

[0073] The automobile fuel tank mounting bolt fatigue life prediction system in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0074] See also Figure 6 , Figure 6 A schematic diagram of the structure of a computer device provided in an embodiment of the present application is shown in FIG. Figure 6 As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 6 A processor 10 is taken as an example.

[0075] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0076] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0077] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created based on the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0078] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0079] The computer device further includes a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0080] The embodiments of the present application also provide a computer-readable storage medium. The above-mentioned method according to the embodiment of the present application can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0081] An embodiment of the present application provides a computer program product, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform a method according to any embodiment of the present application.

[0082] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

[0083] The systems or modules described in the above embodiments may be implemented by computer chips or entities, or by products having certain functions. A typical implementation device is a computer. Specifically, the computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0084] For the convenience of description, the above devices are described as being divided into various units according to their functions. Of course, when implementing this application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0085] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0086] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0087] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0089] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0090] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0091] The above are merely embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

[0092] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A method for predicting fatigue life of automobile fuel tank mounting bolts, characterized in that: The method comprises: A finite element model of the fuel tank system is constructed, wherein: a discretized grid is constructed based on the digital model of each component of the fuel tank system; the weight and center of mass of each component of the fuel tank system are obtained, and the discretized grid is weighted; if the discretized grid after the weight of the model meets the consistency standard with the weight and center of mass of the actual component, simulated weld points, simulated contacts, simulated bolt preload units, and bolt load lifting units are set based on the discretized grid after the weight of the model to obtain the finite element model of the fuel tank system; Obtain the random vibration spectrum of the fuel tank while correlating the vehicle warranty life with the vehicle proving ground road test specifications; Based on the statistical analysis of rain flow, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum; If the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model to extract the mounting bolt load parameters, wherein the mounting bolt load parameters include the load value of the mounting bolt, wherein: the load value of the mounting bolt is obtained by calculating the vector displacement of any point in the bolt loading unit; the vector displacement of any point in the bolt loading unit is determined as follows: the bolt loading unit includes a first node, a second node, and a third node connected in sequence, the first node is used to couple one end of the bolt connection, and the third node is used to couple the other end of the bolt connection, and the unit shape functions of the first node, the second node, and the third node are respectively: In the above formula, is a random number between -1 and 1; 、 、 are the element shape functions of the first, second and third nodes respectively; The vector displacement of any point in the bolt load-carrying unit is: In the above formula, is the vector displacement of any point in the bolt load unit, is the vector displacement of the first node, is the vector displacement of the second node, is the vector displacement of the third node; The bolt fatigue life is predicted based on the installation bolt load parameters.

2. The method according to claim 1, characterized in that The vehicle warranty life is associated with the vehicle proving ground road test specifications, and is used to indicate that a first road surface stimulus received by the vehicle in the proving ground is equivalent to a second road surface stimulus received within the warranty life.

3. The method according to claim 1, characterized in that If the weight and center of mass of the discretized grid of the model after weighting do not meet the consistency standard with the weight and center of mass of the actual component, the cell density of the discretized grid is reset to adjust the weight and center of mass of the discretized grid.

4. The method according to claim 1, wherein The method of converting the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum specifically includes: Based on rain flow statistical analysis, the random vibration spectrum is equivalently converted into a load cycle to obtain the load amplitude and the number of cycles of the load cycle; Based on the load amplitude and the number of cycles of the load cycle, a block vibration spectrum is constructed.

5. A system for predicting fatigue life of bolts for mounting fuel gas tanks of automobiles, capable of implementing the method for predicting fatigue life of bolts for mounting fuel gas tanks of automobiles as claimed in any one of claims 1 to 4, characterized in that: The system comprises: Finite element model building module, used to build a finite element model of the fuel tank system; A block vibration spectrum construction module is used to obtain the random vibration spectrum of the fuel tank when the vehicle warranty life is associated with the vehicle proving ground road test specifications; and is used to convert the random vibration spectrum into a load cycle based on rain flow statistical analysis to obtain a block vibration spectrum; A bolt fatigue prediction module is used to predict the fatigue life of the bolt based on the installation bolt load parameters. If the deviation between the first pseudo-damage value of the block vibration spectrum and the second pseudo-damage value of the random vibration spectrum is within a set threshold, the block vibration spectrum is loaded into the finite element model to extract the installation bolt load parameters.

6. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the method according to any one of claims 1 to 4.

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