Method, system, equipment, medium and product for predicting service life of blade structure

Abstract

The present application discloses a method, system, device, medium and product for predicting the service life of a blade structure, and relates to the field of technical prediction of unmanned aerial vehicle structures in the machinery industry. The method comprises the following steps: performing a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear; performing a stress relaxation test on the blade structure to be tested to determine stress relaxation experimental data of load variation over time; determining material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation experimental data; and predicting the service life of the blade structure to be tested under the current load using the relationship between stress relaxation and damage constructed based on the material parameters. The present application can shorten the test time and reduce manpower and financial costs.

Description

Technical Field

[0001] The present application relates to the field of UAV structural technology prediction in the machinery industry, and in particular to a method, system, equipment, medium and product for predicting the service life of a blade structure. Background Art

[0002] Drone technology has become an important part of contemporary science and technology. In recent years, the rapid development of drone technology and the continuous expansion of its application areas have brought many conveniences and new development opportunities to society. As a representative of emerging industries, the drone industry has shown broad prospects. Especially in the field of firefighting, drones have been widely used as an innovative industrial technology. Many firefighting agencies in China have successfully used drones to conduct fire scene reconnaissance and monitoring, as well as to deliver rescue supplies, and have achieved remarkable results.

[0003] Drone propeller blades are important components for drone flight. They generate lift and thrust through rotation, allowing drones to take off, hover and fly. Blade materials are usually high-strength materials that are lightweight and durable. During service, drone propeller blades are subject to inertial forces caused by the high-speed rotation of the blades, which places strict requirements on the structural strength and service life of the blades.

[0004] When firefighting drones are engaged in firefighting operations, the ambient temperature changes, causing the drone propeller blades to not only bear the inertial force, but also the stable load (creep damage) caused by long-term high-temperature operation, causing the blades as a whole to bear a time-related complex load. These conditions will cause the material to deteriorate and be damaged as the service time increases, and gradually reduce the stability and safety of the equipment operation. Therefore, it is very important to accurately and quickly predict the service life of drone propeller blades.

[0005] At present, the commonly used service life prediction methods for blade structures are mainly the experimental measurement method of blade service life (i.e., the experimental method) and the finite element simulation calculation method (i.e., the CAE simulation calculation method) in computer-aided engineering (CAE) for blade structures. Among them, the experimental method applies a constant load through a mechanical testing machine and provides a high temperature environment through a high temperature environment box to simulate the working load and environment of the propeller blade of a drone, so that the blade structure is in a high temperature creep stress state. Usually, the experiment lasts for several months to measure the service life of the blade structure, and the measurement efficiency is low. The CAE simulation calculation method involves a lot of algorithm programming and computational mechanics knowledge, which requires extremely high knowledge reserves and scientific research levels of engineers, and usually takes a long time for CAE calculations of large structures. In summary, the two commonly used methods currently have high requirements for personnel, facilities, time and money, and are time-consuming to implement, with high human and financial costs. Summary of the invention

[0006] The purpose of this application is to provide a method, system, device, medium and product for predicting the service life of a blade structure, so as to solve the problem that the existing life prediction methods are time-consuming and costly.

[0007] To achieve the above objectives, this application provides the following solutions.

[0008] In a first aspect, the present application provides a method for predicting the service life of a blade structure, comprising the following steps.

[0009] A tensile test is performed on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear.

[0010] A stress relaxation experiment is performed on the blade structure to be tested to determine stress relaxation experimental data of load variation over time; the stress relaxation experimental data includes time and a drop in load corresponding to the time.

[0011] The material parameters of the blade structure to be tested are determined based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data.

[0012] The service life of the blade structure to be tested under the current load is predicted using the relationship between stress relaxation and damage constructed based on the material parameters.

[0013] In a second aspect, the present application provides a service life prediction system for a blade structure, comprising the following modules.

[0014] The maximum load determination module is used to perform a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear.

[0015] The stress relaxation experimental data determination module is used to perform a stress relaxation experiment on the blade structure to be tested to determine stress relaxation experimental data of load changing with time; the stress relaxation experimental data includes time and a drop in load corresponding to the time.

[0016] The material parameter value determination module is used to determine the material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data.

[0017] The service life prediction module is used to predict the service life of the blade structure to be tested under the current load by using the relationship between stress relaxation and damage constructed based on the material parameters.

[0018] In a third aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described methods for predicting the service life of a blade structure.

[0019] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-described methods for predicting the service life of a blade structure.

[0020] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-described methods for predicting the service life of a blade structure.

[0021] According to the specific embodiments provided by the present application, the present application discloses the following technical effects: the present application determines the maximum load of the blade structure to be tested and the stress relaxation test data by performing a tensile test and a stress relaxation test on the blade structure to be tested, and obtains the specific values ​​of the material parameters of the blade structure to be tested, thereby constructing a relationship between stress relaxation and damage to predict the service life of the blade structure to be tested under the current load. Compared with the experimental method and the CAE simulation calculation method, the present application does not require long-term measurements to obtain the service life. Only the desired material parameters are obtained through tensile tests and stress relaxation tests, and then the relationship between stress relaxation and damage is constructed to predict the service life of the blade structure to be tested under the current load, thereby shortening the test time. In addition, the prediction method of the present application is simple, does not require a large amount of algorithm programming and knowledge in the field of computational mechanics, has low requirements on the knowledge reserve and scientific research level of engineers, and reduces human and financial costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a flow chart of a method for predicting the service life of a blade structure in one embodiment of the present application.

[0024] Figure 2 A load-deformation curve diagram in a tensile test provided in one embodiment of the present application.

[0025] Figure 3 A load-time curve diagram in a stress relaxation experiment provided in one embodiment of the present application.

[0026] Figure 4 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only 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 ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0029] like Figure 1 As shown, an embodiment of the present application provides a method for predicting the service life of a blade structure. The method is executed by a computer device, and can be specifically executed by a computer device such as a terminal or a server alone, or by a terminal and a server together, and includes the following steps 101 to 104.

[0030] Step 101: performing a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear.

[0031] Step 102: performing a stress relaxation experiment on the blade structure to be tested to determine stress relaxation experiment data of load variation over time; the stress relaxation experiment data includes time and a drop in load corresponding to the time.

[0032] Step 103: Determine the material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data.

[0033] Step 104: predicting the service life of the blade structure to be tested under the current load using the relationship between stress relaxation and damage constructed based on the material parameters.

[0034] In an exemplary embodiment, first, as Figure 2 As shown, a tensile test is performed on the blade structure to obtain the maximum load that the blade structure can withstand. ; “×” is the maximum load of the test piece (i.e. the blade structure to be tested) in the tensile test The corresponding points.

[0035] Secondly, stress relaxation experiments on the blade structure were carried out, such as Figure 3 As shown in the figure, the stress relaxation experimental data of load changing with time is obtained.F Corresponding to a load change rate , obtained in the stress relaxation experiment F and t After the relationship F and It also corresponds one to one, and can also be based on F and t Calculate the slope of the tangent line from the relationship curve.

[0036] (1)

[0037] (2)

[0038] in, is the load change rate, in Newton / second; is the irreversible deformation rate in mm / s; is the elastic modulus of the blade structure, in Pascals; is the plastic deformation rate in mm / s.

[0039] In an exemplary embodiment, step 103 may be replaced by step 201 - step 202 .

[0040] Step 201: constructing an irrecoverable displacement rate expression in the blade structure to be measured according to the current load of the blade structure to be measured, the maximum load and the material parameters.

[0041] Furthermore, the expression for the irrecoverable displacement rate of the blade structure is as follows.

[0042] (3)

[0043] in, is the blade deformation proportional coefficient, It is dimensionless and has no units; is the time-dependent index, It is dimensionless and has no units.

[0044] Step 202: Fitting the logarithmic form of the irrecoverable displacement rate expression to the stress relaxation experimental data to generate the numerical value of the material parameter; the material parameter includes the blade deformation proportional coefficient.

[0045] Furthermore, taking the logarithm of both sides of formula (3) yields:

[0046] (4)

[0047] By fitting formula (4) with the relaxation experimental data, we can obtain Z and nThe specific value of .

[0048] In an exemplary embodiment, step 104 specifically includes: introducing the service life of the blade structure to be measured, integrating the relationship between the stress relaxation and damage, and predicting the service life of the blade structure to be measured under the current load.

[0049] Furthermore, the relationship between stress relaxation and damage is shown in formula (5).

[0050] (5)

[0051] in, is the damage rate of the blade structure to be tested, It is dimensionless and has no units; is the damage of the blade structure to be tested, is dimensionless and has no units. m is the damage index of the blade structure, m is a constant.

[0052] Integrating formula (5) yields:

[0053] (6)

[0054] in, is the damage tolerance of the blade structure, It is dimensionless and has no unit, that is, the maximum amount of damage that the blade structure can bear. Its value cannot be greater than 1. For the blade structure, it can be taken as about 0.9. is the service life in seconds, and can be obtained by formula (6): expression.

[0055] (7)

[0056] k To simplify the formula, k is dimensionless and has no units. .

[0057] At this point, the current load can be obtained F The service life of the blade structure under the action of force can be predicted quickly to achieve the purpose of quickly predicting the service life of the blade structure.

[0058] The core idea of ​​this application is to calculate the relationship between plastic deformation rate and load (i.e., irreversible displacement rate expression) through stress relaxation test data, and then combine the relationship between stress relaxation and damage to derive the service life of the blade structure. The stress relaxation experiment used in this application actually involves the stress relaxation test data of the blade structure in the service environment, so the predicted service life is more accurate and reliable, and the experimental cost is controllable and can be completely determined by the implementing unit or individual.

[0059] Taking the propeller blade structure of a drone as an example, this application conducts a tensile test on the blade structure to determine the maximum load that the blade structure can bear. Then, the stress relaxation experiment of the propeller blade structure of the UAV was carried out, and the stress relaxation experimental data was fitted to determine Z and n Finally, the service life of the blade structure is calculated using the relationship between stress relaxation and damage to achieve the purpose of predicting the service life of the blade structure.

[0060] The service life prediction method of the blade structure provided in this application is concise, easy to understand and easy for engineers to master and use. It does not require large-scale long-term CAE and theoretical calculations, and the experimental parameters required to be determined in the process are few and accurate. This application uses a short stress relaxation experiment, which is simple and easy to implement. It only needs to determine three experimental parameters (i.e., maximum load , time-dependent index and the damage index of the blade structure ) can achieve the purpose of quickly predicting the service life of the UAV propeller blade structure.

[0061] The present application can be used to predict the service life of UAV propeller blades under different service environments, solving the difficult problem of engineers quickly and accurately predicting the service life of UAV propeller blades, and providing an effective solution for the safety assessment and failure analysis of UAV propeller blades.

[0062] Based on the same inventive concept, the embodiment of the present application also provides a blade structure service life prediction system for implementing the blade structure service life prediction method involved above. The implementation scheme for solving the problem provided by the system is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the service life prediction system for one or more blade structures provided below can refer to the limitations of the blade structure service life prediction method above, and will not be repeated here.

[0063] In an exemplary embodiment, a service life prediction system for a blade structure is provided, comprising the following modules.

[0064] The maximum load determination module is used to perform a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear.

[0065] The stress relaxation experimental data determination module is used to perform a stress relaxation experiment on the blade structure to be tested to determine stress relaxation experimental data of load changing with time; the stress relaxation experimental data includes time and a drop in load corresponding to the time.

[0066] The material parameter value determination module is used to determine the material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data.

[0067] The service life prediction module is used to predict the service life of the blade structure to be tested under the current load by using the relationship between stress relaxation and damage constructed based on the material parameters.

[0068] In an exemplary embodiment, a computer device is provided, which may be a server or a terminal. Figure 4 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store service life prediction data of the blade structure. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for predicting the service life of a blade structure is implemented.

[0069] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0070] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0071] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0072] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0073] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0074] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0075] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for predicting the service life of a blade structure, characterized in that: The service life prediction method of the blade structure comprises: Performing a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear; Performing a stress relaxation experiment on the blade structure to be tested to determine stress relaxation experimental data of load variation over time; the stress relaxation experimental data includes time and a drop in load corresponding to the time; Determining the material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data, specifically includes: Constructing an irrecoverable displacement rate expression in the blade structure to be measured according to the current load of the blade structure to be measured, the maximum load and the material parameters; Fitting the logarithmic form of the irrecoverable displacement rate expression to the stress relaxation experimental data to generate the numerical value of the material parameter; the material parameter includes the blade deformation proportional coefficient; Predicting the service life of the blade structure to be tested under the current load by using the relationship between stress relaxation and damage constructed based on the material parameters, specifically includes: The service life of the blade structure to be measured is introduced, the relationship between the stress relaxation and the damage is integrated, and the service life of the blade structure to be measured under the current load is predicted.

2. The service life prediction method of a blade structure according to claim 1, characterized in that: The irreversible displacement rate expression is: ; in, is the plastic deformation rate; is the current load; is the maximum load; is the blade deformation proportional coefficient; is a time-dependent index.

3. The service life prediction method of a blade structure according to claim 2, characterized in that: The relationship between stress relaxation and damage is: ; in, is the damage rate of the blade structure to be tested; is the damage of the blade structure to be tested; is the blade deformation proportional coefficient; is the current load; is the maximum load; is the time-dependent index; is the damage index of the blade structure.

4. The service life prediction method of a blade structure according to claim 3, characterized in that: The service life of the blade structure to be tested for: ; in, is the damage tolerance of the blade structure; To simplify the formula, .

5. A blade structure service life prediction system, characterized in that: The service life prediction system of the blade structure comprises: A maximum load determination module, used to perform a tensile test on the blade structure to be tested to determine the maximum load that the blade structure to be tested can bear; A stress relaxation experimental data determination module is used to perform a stress relaxation experiment on the blade structure to be tested to determine stress relaxation experimental data of load variation over time; the stress relaxation experimental data includes time and a drop in load corresponding to the time; The material parameter value determination module is used to determine the material parameters of the blade structure to be tested based on the current load of the blade structure to be tested, the maximum load and the stress relaxation test data, and specifically includes: Constructing an irrecoverable displacement rate expression in the blade structure to be measured according to the current load of the blade structure to be measured, the maximum load and the material parameters; Fitting the logarithmic form of the irrecoverable displacement rate expression to the stress relaxation experimental data to generate the numerical value of the material parameter; the material parameter includes the blade deformation proportional coefficient; The service life prediction module is used to predict the service life of the blade structure to be tested under the current load by using the relationship between stress relaxation and damage constructed based on the material parameters, and specifically includes: The service life of the blade structure to be measured is introduced, the relationship between the stress relaxation and the damage is integrated, and the service life of the blade structure to be measured under the current load is predicted.

6. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the service life prediction method for a blade structure according to any one of claims 1 to 4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the service life prediction method of the blade structure described in any one of claims 1 to 4 is implemented.

8. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the service life prediction method of the blade structure described in any one of claims 1 to 4 is implemented.

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