Fatigue life prediction method and system for mounting bolt of automobile fuel gas tank and storage medium

Abstract

The invention relates to the technical field of mechanical engineering, and discloses an automobile fuel gas tank mounting bolt fatigue life prediction method and system and a storage medium, and the method comprises the steps: constructing a finite element model of a fuel gas tank system; acquiring a random vibration spectrum of the fuel gas tank under the condition that the whole vehicle quality guarantee life is associated with the whole vehicle test field road test specification; based on rain flow statistical analysis, equivalently converting the random vibration spectrum into a load cycle to obtain a block-shaped vibration spectrum; if the deviation between the pseudo-damage value of the block-shaped vibration spectrum and the pseudo-damage value of the random vibration spectrum is within a set threshold value, loading the block-shaped vibration spectrum into a finite element model, and extracting a mounting bolt load parameter; based on the load parameters of the mounting bolt, the fatigue life of the bolt is predicted, 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 fastening performance and cost of the bolt 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 bolts for mounting a fuel tank of an automobile. Background Art

[0002] Fuel tank trucks are usually used to transport various types of fuel gas, including LNG (liquefied natural gas) trucks, CNG (compressed natural gas) vehicles, LPG (liquefied petroleum gas) vehicles, etc. At present, fuel tanks are mainly installed on the vehicle body beams through bolts. When the vehicle passes through undulating roads during transportation, the load on the vehicle tires will be transmitted to the fuel tanks through the beams, causing the fuel tanks to shake violently. Reliable bolt tightening can prevent the tanks from sliding and falling, and the fatigue life prediction of the bolts is an important task in the design of the fuel tank system. 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 a fuel tank system; obtaining a random vibration spectrum of the fuel tank when the warranty life of the whole vehicle is associated with the road test specifications of a whole vehicle test field; based on rain flow statistical analysis, converting the random vibration spectrum into a load cycle to obtain a block vibration spectrum; if the deviation between a first pseudo-damage value of the block vibration spectrum and a 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 bolts.

[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 effective control of bolt tightening performance and cost.

[0007] Optionally, the whole vehicle warranty life is associated with the whole vehicle proving ground road test specification, and is used to characterize that a first road surface excitation received by the whole vehicle in the proving ground is equivalent to a second road surface excitation received within the warranty life period.

[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 tank system specifically includes: constructing a discretized grid based on the digital model of each component of the fuel tank system; obtaining the weight and center of mass of each component of the fuel tank system, and weighting the discretized grid; if the weight and center of mass of the discretized grid after the model weighting meet 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 tank system.

[0010] Optionally, if the weight and center of mass of the discretized grid after the model is weighted 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.

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

[0012] Optionally, the bolt load-carrying unit comprises 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, 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 unit shape functions of the first node, the second node, and the third node, respectively;

[0015] The vector displacement of any point in the bolt loading 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, which specifically includes: 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 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.

[0020] Optionally, the warranty period of the whole 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 warranty life of the whole vehicle is associated with the road test specifications of the whole vehicle test field; 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, including 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 drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. 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 paying any creative work.

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

[0028] Figure 2 A flow chart 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 system for predicting fatigue life of bolts for mounting a fuel tank of an automobile 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] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution 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 creative work are within the scope of protection of the present application.

[0034] Fuel tank trucks are usually used to transport various types of fuel gas, including LNG (liquefied natural gas) trucks, CNG (compressed natural gas) vehicles, LPG (liquefied petroleum gas) vehicles, etc. At present, fuel tanks are mainly installed on the vehicle body beams through bolts. When the vehicle passes through undulating roads during transportation, the load on the vehicle tires will be transmitted to the fuel tanks through the beams, causing the fuel tanks to shake violently. Reliable bolt tightening can prevent the tanks from sliding and falling, and the fatigue life prediction of the bolts is an important task in the design of the fuel tank system.

[0035] Fuel tank vehicles have complex operating conditions. How to accurately obtain the random vibration load spectrum of fuel tanks is the basis and difficulty of fatigue life prediction of mounting bolts. Fuel tanks are installed with multiple bolts. It is necessary to accurately decompose the random vibration load spectrum of fuel tanks to the hard points of multiple bolt connections, and then obtain the vibration load of multiple bolts, which is not possible in current 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. A simulation environment is built, 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 a 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 bolts 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 A flowchart of a method for predicting fatigue life of a bolt for mounting a fuel tank of an automobile provided in an embodiment of the present application is shown in FIG. 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 the fuel tank system, after the bolts are installed, the internal load cannot be directly measured. The finite element model discretizes the continuous physical system into a finite number of small units, which can be used to accurately simulate the complex system. By constructing a finite element model of the fuel tank system, the physical prototype (that is, the actual fuel tank system) can be numerically simulated and analyzed, reducing the dependence on the physical prototype, reducing costs and development time.

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

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

[0043] Among them, the vehicle proving ground road test specifications are a series of test standards and procedures formulated to ensure the performance, safety and reliability of the vehicle under actual road conditions. These specifications usually include tests on the vehicle's power performance, braking performance, handling stability, environmental performance, comfort and durability. The vehicle warranty life usually refers to the quality assurance commitment made to the overall quality of the vehicle within 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 the test data of the whole vehicle within the warranty life, it usually takes too much time and cost, which can be obtained through equivalent incentives. Among them, the warranty life of the whole vehicle is associated with the road test specifications of the whole vehicle test field, which is used to characterize that the first road surface incentive received by the whole vehicle in the test field is equivalent to the second road surface incentive received within the warranty life period. Among them, the first road surface refers to the ordinary road surface on which the user drives, and the second road surface refers to the test field road surface. In order to obtain the test data of the whole vehicle within the warranty life, it can be obtained by applying equivalent incentives to the whole vehicle on the test field road, thereby greatly shortening the test time and cost. For example, in order to obtain the performance test data of the whole vehicle within the warranty life of 10 years or 200,000 kilometers, based on equivalent incentives, equivalent incentives can be applied to the whole vehicle at the test field, and the performance test data obtained by driving the whole vehicle for 3 months at the test field will be regarded as the performance test data of the whole vehicle within the warranty life.

[0045] For example, to obtain the random vibration spectrum of the vehicle within the warranty life, the warranty life of the vehicle is associated with the road test specifications of the vehicle test field, and test data equivalent to the warranty life can be obtained in a shorter time in the test field, that is, an equivalent random vibration spectrum is obtained. Among them, the random vibration spectrum is used to characterize the excitation transmission from the road surface to the tire and the fuel tank.

[0046] Specifically, a plurality of 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] 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 usually contain a large number of data points, and it is very complicated to analyze these data directly. Through rain flow statistical analysis, random vibration spectra can be converted into block vibration spectra, simplifying complex random vibration into a series of periodic blocks, each with a clear amplitude and number of cycles, which is conducive to simplifying the analysis process and better simulating actual load conditions, thereby 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 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 the abaqus simulation software, the block vibration spectrum is loaded into the finite element model, which can be realized by the modal superposition method or the direct time history analysis method. Run the simulation software to calculate the response of the mounting bolt under the block vibration spectrum, including the displacement, so as to solve and obtain the load parameters of the mounting bolt. The mounting bolt load parameters include the load value of the mounting bolt and the number of cycles of the block vibration spectrum. When the stiffness of the mounting bolt is known, the load value of the mounting bolt can be obtained by calculating the displacement of the mounting bolt.

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

[0057] The installation bolt load parameters specifically include the maximum load value, the minimum load value, and the number of cycles of the block vibration spectrum. The installation bolt load parameters are 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 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, 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 effective control of 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 tank system; the weight and center of mass of each component of the fuel tank system are obtained, and the discretized grid is model-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 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 flow chart 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 component, 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, and if so, setting simulated welds, simulated contacts, simulated bolt preloads and bolt load-carrying 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 welding points; 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; 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, and 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 unit shape functions of the first node, the second node, and the third node, respectively;

[0066] The vector displacement of any point in the bolt load-carrying 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 rain flow statistical analysis, the random vibration spectrum is equivalently converted into load cycles to obtain a block vibration spectrum, specifically including: based on rain flow statistical analysis, the random vibration spectrum is equivalently converted into load cycles 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 a finite element model of a CNG gas tank system provided in an embodiment of the present application. Figure 4 , Figure 4 A flow chart 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 a 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 specification of the vehicle test field. 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 the set threshold, the block vibration spectrum is loaded into the finite element model of the CNG gas tank system, and the mounting bolt load parameters are extracted. Based on the mounting bolt load parameters, the fatigue life of the bolt is predicted, which solves the technical problem of fatigue life prediction of mounting bolts of automobile fuel tanks and achieves the technical effect of effective control of bolt tightening performance and cost.

[0072] Please refer to Figure 5 , Figure 5A 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. The fatigue life prediction system for mounting bolts of an automobile fuel tank includes: a finite element model construction module, which is used to construct a finite element model of the fuel tank system; a block vibration spectrum construction module, which is used to obtain 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 a bolt fatigue prediction module, which is used to convert the random vibration spectrum into load cycles based on rain flow statistical analysis to obtain a block vibration spectrum; and a bolt fatigue prediction module, which is used to predict 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.

[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, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, 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 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. Similarly, multiple computer devices can be connected, and each device provides some 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 a dedicated 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 executable by at least one processor 10, so that at least one processor 10 executes 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, an application required for at least one function; the data storage area may store data created according to 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 arranged 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 comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0080] The embodiment of the present application also provides a computer-readable storage medium. The above method according to the embodiment of the present application can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, 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 hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. 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] The embodiment of the present application provides a computer program product, which includes computer instructions, which are stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method of any embodiment of the present application.

[0082] Although the embodiments of the present application are described in conjunction with 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 are all 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 with 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 smart phone, 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 device is described in various units according to their functions. Of course, when implementing the present 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 may be provided as methods, systems, or computer program products. Therefore, the present application may 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 may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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 capable of directing a computer or other programmable data processing device to operate 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 A 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 operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. 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 "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0090] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0091] The above are only 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 modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

[0092] Although the embodiments of the present application have been described in conjunction with 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 are all within the scope defined by the appended claims.

Claims

1. A method for predicting fatigue life of bolts for mounting a fuel tank of an automobile, characterized in that: The method comprises: Construct a finite element model of the fuel tank system; Obtain the random vibration spectrum of the fuel tank when the vehicle warranty life is associated 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 installation bolt load parameter; Based on the installation bolt load parameters, the bolt fatigue life is predicted.

2. The method according to claim 1, characterized in that The whole vehicle warranty life is associated with the whole vehicle proving ground road test specification, and is used to indicate that a first road surface stimulus received by the whole 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 The construction of the finite element model of the fuel tank system specifically includes: Based on the digital model of each component of the fuel tank system, a discretized grid is constructed; Obtaining the weight and center of mass of each component of the fuel tank system, and performing model weighting on the discretized grid; If the weight and center of mass of the discretized grid of the model after weighting meet the consistency standard with the actual parts, then based on the discretized grid of the model after weighting, simulated welding points, simulated contacts, simulated bolt pre-tightening and bolt loading units are set to obtain the finite element model of the fuel tank system.

4. The method according to claim 3, 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.

5. The method according to claim 1, characterized in that The mounting bolt load parameters include the load value of the mounting bolt and the number of cycles of the block vibration spectrum.

6. The method according to claim 5, characterized in that The step of loading the block vibration spectrum into the finite element model and extracting the installation bolt load parameters specifically includes: obtaining the installation bolt load value by calculating the vector displacement of any point in the bolt loading unit.

7. The method according to claim 6, characterized in that The bolt load-carrying unit comprises 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: In the above formula, ν is a random number between -1 and 1; N1, N2, and N3 are the unit shape functions of the first node, the second node, and the third node, respectively; The vector displacement of any point in the bolt loading unit is: d i =N1·δ1+N2·δ2+N3·δ3 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.

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

9. A fatigue life prediction system for automobile fuel tank mounting bolts, 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 test field road test specification; based on the rain flow statistical analysis, the random vibration spectrum is equivalently converted into a load cycle to obtain a block vibration spectrum; The bolt fatigue prediction module is used to predict the bolt fatigue life according to the installation 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 installation bolt load parameters.

10. 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 8.

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