A method and device for predicting fatigue damage of a transfer

Abstract

This application provides a method and apparatus for predicting fatigue damage of a transfer case, applied in the field of vehicle technology. The method includes: acquiring a calculation flag; if the calculation flag is a stress calculation flag, acquiring multiple first real-time stress values ​​of components in the transfer case within a cycle; if the multiple first real-time stress values ​​include N second real-time stress values, predicting stress fatigue damage of the components within the cycle; if the multiple first real-time stress values ​​include M third real-time stress values, modifying the calculation flag from a stress calculation flag to a strain calculation flag; and predicting strain fatigue damage of the components within the cycle based on the strain calculation flag. In the fatigue damage prediction method of this application embodiment, stress fatigue damage and strain fatigue damage prediction methods are adopted respectively according to the characteristics of the real-time stress values ​​of the components, thereby improving the accuracy of the fatigue damage prediction method.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method and apparatus for predicting fatigue damage of a transfer case. Background Technology

[0002] Generally, four-wheel drive vehicles have a transfer case to enable both two-wheel drive and four-wheel drive transmission. Transfer cases are prone to fatigue due to prolonged operation, and predicting fatigue damage to transfer case components is beneficial for understanding their condition. Traditional fatigue damage calculation methods only collect data during testing and process it afterward. They do not consider the real-time stress characteristics of the components during testing to predict fatigue damage, resulting in low accuracy in fatigue damage prediction methods. Summary of the Invention

[0003] This application provides a method and apparatus for predicting fatigue damage in a transfer case, in order to solve the problem of low accuracy in existing fatigue damage prediction methods.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows:

[0005] Firstly, embodiments of this application provide a method for predicting fatigue damage to a transfer case. The method includes:

[0006] Get the calculation flag;

[0007] When the calculation flag is the stress calculation flag, multiple first real-time stress values ​​of the components in the transfer case are obtained within the cycle.

[0008] When the plurality of first real-time stress values ​​include N second real-time stress values, predict the stress fatigue damage of the component in the cycle, wherein the second real-time stress value is less than a set value, and N is a positive integer;

[0009] When the plurality of first real-time stress values ​​include M third real-time stress values, the calculation flag is changed from a stress calculation flag to a strain calculation flag, and the third real-time stress value is greater than the set value;

[0010] Based on the strain calculation flag, the strain fatigue damage of the component is predicted during the cycle, where M is a positive integer.

[0011] Optionally, predicting stress fatigue damage of the component during the cycle when the plurality of first real-time stress values ​​include N second real-time stress values ​​includes:

[0012] When the plurality of first real-time stress values ​​include N second real-time stress values, the stress amplitude and the average first stress of the component within the cycle period are calculated based on the N second real-time stress values.

[0013] Based on the stress amplitude and the first average stress, the stress fatigue damage of the component during the cycle is predicted.

[0014] Optionally, predicting strain fatigue damage of the component within the cycle based on the strain calculation flag includes:

[0015] Based on the strain calculation flag, M target real-time strain values ​​are calculated according to M first transfer case input torque values ​​respectively;

[0016] Calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively;

[0017] Based on the M target real-time stress values, calculate the first strain amplitude and the second average stress value of the component within the cycle period;

[0018] Based on the first strain amplitude and the second average stress, the strain fatigue damage of the component during the cycle is predicted.

[0019] Optionally, the step of calculating the M target real-time stress values ​​based on the M target real-time strain values ​​includes:

[0020] A first target real-time stress value is determined based on the obtained first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is first applied to the component, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is first applied to the component.

[0021] The first strain increment value is calculated based on the obtained second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, where K is a positive integer;

[0022] Calculate the first stress increment value based on the first strain increment value;

[0023] Based on the second target real-time stress value and the first stress increment value, a third target real-time stress value is calculated, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time.

[0024] The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

[0025] Optionally, the method further includes:

[0026] Under certain preset conditions, the load is determined to be applied to the component for the first time. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

[0027] Optionally, when the calculation flag is a stress calculation flag, obtaining multiple first real-time stress values ​​of the components in the transfer case within a cycle includes:

[0028] Multiple sets of different parameter pairs are obtained, wherein each set of parameter pairs includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value.

[0029] Based on the multiple sets of different parameter pairs, a simulation model is established. The inputs of the simulation model include engine torque, transmission ratio, hydraulic torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration. The output of the simulation model includes the transfer case input torque.

[0030] Multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia, and multiple actual values ​​of transmission acceleration are input into the simulation model to determine the corresponding actual values ​​of multiple transfer case input torque.

[0031] Based on the actual input torque values ​​of the multiple transfer cases, the first real-time stress values ​​of the components in the transfer case within the cycle are determined.

[0032] Optionally, the method further includes:

[0033] When the calculation flag is the strain calculation flag, obtain the H second transfer case input torque values ​​of the components in the transfer case within the cycle;

[0034] Calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case respectively;

[0035] Calculate H real-time stress values ​​based on the H real-time strain values ​​respectively;

[0036] Based on the H real-time stress values, calculate the second strain amplitude and the third average stress value;

[0037] Based on the second strain amplitude and the third average stress, the strain fatigue damage of the component during the cycle is predicted.

[0038] Secondly, embodiments of this application also provide a transfer case fatigue damage prediction device. The transfer case fatigue damage prediction device includes:

[0039] The first acquisition module is used to acquire the calculation flag bit;

[0040] The second acquisition module is used to acquire multiple first real-time stress values ​​of the components in the transfer case within the cycle when the calculation flag is a stress calculation flag.

[0041] The first prediction module is used to predict stress fatigue damage of the component in the cycle when the plurality of first real-time stress values ​​include N second real-time stress values, wherein the second real-time stress values ​​are less than a set value and N is a positive integer.

[0042] The first modification module is used to modify the calculation flag bit from the stress calculation flag bit to the strain calculation flag bit when the plurality of first real-time stress values ​​include M third real-time stress values, and the third real-time stress value is greater than the set value;

[0043] The second prediction module is used to predict the strain fatigue damage of the component within the cycle based on the strain calculation flag, where M is a positive integer.

[0044] Optionally, the first prediction module includes:

[0045] The first calculation unit is used to calculate the stress amplitude and the average first stress of the component in the cycle period based on the N second real-time stress values ​​when the plurality of first real-time stress values ​​include N second real-time stress values.

[0046] The first prediction unit is used to predict stress fatigue damage of the component during the cycle based on the stress amplitude and the first average stress.

[0047] Optionally, the second prediction module includes:

[0048] The second calculation unit is used to calculate M target real-time strain values ​​based on the strain calculation flag bit and M first transfer case input torque values ​​respectively.

[0049] The third calculation unit is used to calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively;

[0050] The fourth calculation unit is used to calculate the first strain amplitude and the second average stress of the component within the cycle based on the M target real-time stress values.

[0051] The second prediction unit is used to predict the strain fatigue damage of the component during the cycle based on the first strain amplitude and the second average stress.

[0052] Optionally, the third computing unit includes:

[0053] The first determining subunit is used to determine the first target real-time stress value based on the acquired first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the first time, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the first time.

[0054] The first calculation subunit is used to calculate the first strain increment value based on the acquired second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, and K is a positive integer;

[0055] The second calculation subunit is used to calculate the first stress increment value based on the first strain increment value;

[0056] The third calculation subunit is used to calculate the third target real-time stress value based on the second target real-time stress value and the first stress increment value, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time.

[0057] The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

[0058] Optionally, the device further includes:

[0059] The first determining module is used to determine that a load is applied to the component for the first time when preset conditions are met. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

[0060] Optionally, the second acquisition module includes:

[0061] The first acquisition unit is used to acquire multiple sets of different parameter pairs, wherein each parameter pair includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value.

[0062] The first establishment unit is used to establish a simulation model based on the multiple sets of different parameter pairs. The inputs of the simulation model include engine torque, transmission speed ratio, hydraulic torque converter speed ratio, transfer case speed ratio, transmission efficiency, equivalent transmission inertia and transmission acceleration. The output of the simulation model includes transfer case input torque.

[0063] The first determining unit is used to input multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia and multiple actual values ​​of transmission acceleration into the simulation model, and to determine multiple actual values ​​of transfer case input torque accordingly.

[0064] The second determining unit is used to determine multiple first real-time stress values ​​of components in the transfer case within a cycle based on the actual values ​​of the input torque of the multiple transfer cases.

[0065] Optionally, the device further includes:

[0066] The third acquisition module is used to acquire H second transfer case input torque values ​​of the components in the transfer case within the cycle when the calculation flag is the strain calculation flag.

[0067] The first calculation module is used to calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case;

[0068] The second calculation module is used to calculate H real-time stress values ​​based on the H real-time strain values ​​respectively;

[0069] The third calculation module is used to calculate the second strain amplitude and the third average stress value based on the H real-time stress values.

[0070] The third prediction module is used to predict the strain fatigue damage of the component during the cycle based on the second strain amplitude and the third average stress.

[0071] Thirdly, embodiments of this application also provide an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the above-described transfer case fatigue damage prediction method.

[0072] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the transfer case fatigue damage prediction method described above.

[0073] The transfer case fatigue damage prediction method of this application includes: acquiring a calculation flag bit; when the calculation flag bit is a stress calculation flag bit, acquiring multiple first real-time stress values ​​of components in the transfer case within a cycle; when the multiple first real-time stress values ​​include N second real-time stress values, predicting stress fatigue damage of the components within the cycle, where the second real-time stress values ​​are less than a set value and N is a positive integer; when the multiple first real-time stress values ​​include M third real-time stress values, modifying the calculation flag bit from a stress calculation flag bit to a strain calculation flag bit, where the third real-time stress values ​​are greater than the set value; and predicting strain fatigue damage of the components within the cycle based on the strain calculation flag bit, where M is a positive integer. In the fatigue damage prediction method of this application, stress fatigue damage and strain fatigue damage prediction methods are used respectively according to the characteristics of the real-time stress values ​​of the components, thereby improving the accuracy of the fatigue damage prediction method. Attached Figure Description

[0074] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0075] Figure 1 This is one of the flowcharts of the transfer case fatigue damage prediction method provided in the embodiments of this application;

[0076] Figure 2 This is the second flowchart of the transfer case fatigue damage prediction method provided in the embodiments of this application;

[0077] Figure 3This is the third flowchart of the transfer case fatigue damage prediction method provided in the embodiments of this application;

[0078] Figure 4 This is a structural diagram of a transfer case fatigue damage prediction device provided in an embodiment of this application;

[0079] Figure 5 This is a structural diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0080] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0081] This application provides a method for predicting fatigue damage to a transfer case. See also... Figure 1 , Figure 1 This is a flowchart of the transfer case fatigue damage prediction method provided in the embodiments of this application, such as... Figure 1 As shown, it includes the following steps:

[0082] Step 101: Obtain the calculation flag bit;

[0083] In this step, see Figure 2 First, it is necessary to determine whether it is a stress calculation process or a strain calculation process based on the preset calculation flags.

[0084] Step 102: If the calculation flag is the stress calculation flag, obtain multiple first real-time stress values ​​of the components in the transfer case within the cycle.

[0085] In this step, if the calculation flag is set to the stress calculation flag, the stress calculation process is followed. Furthermore, the cycle period can be understood as the stress values ​​exhibiting a regular, consistent time interval. It should be noted that the transfer case contains many components, and different components experience different loads; even the same component may be under different loads in different gears. For example, in gear 2H, the chain in the transfer case idles without load, while in gears 4H and 4L it bears a load. In this case, for loaded components such as the chain or output shaft, it is necessary to obtain multiple first real-time stress values ​​within the cycle period, provided that the load acquisition conditions are met.

[0086] Step 103: When the plurality of first real-time stress values ​​include N second real-time stress values, predict the stress fatigue damage of the component in the cycle, wherein the second real-time stress value is less than a set value and N is a positive integer;

[0087] In this step, the first real-time stress value of the component is obtained. If the first real-time stress value of the component is less than a set value, in order to distinguish it from other embodiments of this application, the first real-time stress value less than the set value is replaced by a second real-time stress value. N second real-time stress values ​​of the component are obtained successively in the cycle. Based on the N second real-time stress values, stress fatigue damage of the component in the cycle is predicted.

[0088] Step 104: When the plurality of first real-time stress values ​​include M third real-time stress values, the calculation flag is changed from the stress calculation flag to the strain calculation flag, and the third real-time stress value is greater than the set value.

[0089] In this step, please refer to [link / reference]. Figure 2 When a third real-time stress value greater than the set value is obtained, it indicates that the component has transitioned from elastic deformation to plastic deformation. At this point, the strain calculation process needs to be initiated, so the stress calculation flag needs to be changed to the strain calculation flag.

[0090] Step 105: Based on the strain calculation flag, predict the strain fatigue damage of the component during the cycle, where M is a positive integer.

[0091] In this step, after modifying the stress calculation flag to the strain calculation flag, the strain fatigue damage of the component during the cycle is predicted based on the stress characteristics of the component.

[0092] Generally speaking, from a microscopic perspective, the initiation of fatigue failure is related to local microscopic plasticity. However, from a macroscopic perspective, when the cyclic stress level is low, elastic strain plays a dominant role, and the fatigue life is relatively long, which is called stress fatigue or high-cycle fatigue (Nf>105, where Nf represents the number of cycles that the material undergoes before fatigue failure). When the cyclic stress level is high, plastic strain plays a dominant role, and the fatigue life is relatively short, which is called strain fatigue or low-cycle fatigue.

[0093] In existing fatigue damage prediction methods, data is only collected during testing and processed after collection. However, the real-time stress characteristics of the components are not considered during testing to predict fatigue damage. In the fatigue damage prediction method of this application embodiment, stress fatigue damage and strain fatigue damage prediction methods are adopted according to the characteristics of the real-time stress value of the components, thereby improving the accuracy of fatigue damage prediction methods.

[0094] Optionally, predicting stress fatigue damage of the component during the cycle when the plurality of first real-time stress values ​​include N second real-time stress values ​​includes:

[0095] When the plurality of first real-time stress values ​​include N second real-time stress values, the stress amplitude and the average first stress of the component within the cycle period are calculated based on the N second real-time stress values.

[0096] Based on the stress amplitude and the first average stress, the stress fatigue damage of the component during the cycle is predicted.

[0097] In the transfer case fatigue damage prediction method of this application embodiment, the first average stress value can be calculated by dividing the sum of the largest and smallest second real-time stress values ​​among N second real-time stress values ​​by two. The stress amplitude can be obtained by subtracting the largest second real-time stress value from the first average stress value, or by subtracting the first average stress value from the smallest second real-time stress value among N second real-time stress values. It should be noted that during the calculation of stress fatigue damage, the calculated stress amplitude needs to be corrected. The calculated first average stress value and the corrected stress amplitude are used to predict the stress fatigue damage of the component within the cycle. This application embodiment, based on the characteristics of the real-time stress values ​​of the component, adopts a stress fatigue damage prediction method to improve the accuracy of the fatigue damage prediction method.

[0098] Optionally, predicting strain fatigue damage of the component within the cycle based on the strain calculation flag includes:

[0099] Based on the strain calculation flag, M target real-time strain values ​​are calculated according to M first transfer case input torque values ​​respectively;

[0100] Calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively;

[0101] Based on the M target real-time stress values, calculate the first strain amplitude and the second average stress value of the component within the cycle period;

[0102] Based on the first strain amplitude and the second average stress, the strain fatigue damage of the component during the cycle is predicted.

[0103] In the component fatigue life prediction method of this application embodiment, since the obtained third real-time stress value is greater than the set value, it indicates that the component has transitioned from elastic deformation to plastic deformation, and at this point, the strain calculation process needs to be initiated. First, the target real-time strain value needs to be calculated based on the input torque value of the first transfer case. It should be noted that a relationship table between the transfer case input torque value and the strain value can be established in advance. After obtaining the first transfer case input torque value, the target real-time strain value is determined by querying the relationship table. Then, based on the obtained M target real-time stress values, the first strain amplitude and the second average stress value of the component within the cycle are calculated. The second average stress value can be calculated by dividing the sum of the largest and smallest second real-time stress values ​​among the M third real-time stress values ​​by two. The strain amplitude can be obtained by subtracting the largest third real-time stress value from the second average stress value, or by subtracting the second average stress value from the smallest third real-time stress value. Based on the calculated second average stress value and first strain amplitude, the strain fatigue damage of the component within the cycle is predicted. Based on the characteristics of the real-time stress values ​​of the components, this application embodiment adopts a strain fatigue damage prediction method to improve the accuracy of fatigue damage prediction methods.

[0104] Optionally, the step of calculating the M target real-time stress values ​​based on the M target real-time strain values ​​includes:

[0105] A first target real-time stress value is determined based on the obtained first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is first applied to the component, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is first applied to the component.

[0106] The first strain increment value is calculated based on the obtained second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, where K is a positive integer;

[0107] Calculate the first stress increment value based on the first strain increment value;

[0108] Based on the second target real-time stress value and the first stress increment value, a third target real-time stress value is calculated, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time.

[0109] The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

[0110] In the component fatigue life prediction method of this application embodiment, the methods for obtaining the target real-time stress value by applying load to the component for the first time and by applying load to the component multiple times are different, so they need to be distinguished. For example, if it is the first time a load is applied to the component, the first target real-time stress value is first calculated based on the first target real-time strain value, and this first target real-time stress value is saved. Then, the component is loaded a second time. Based on the obtained target real-time strain value and combined with the first target real-time strain value, the strain increment value compared to the first time is obtained. Based on the strain increment value, the stress increment value is obtained. Then, based on the first target real-time stress value and the stress increment value, the target real-time stress value for the second load applied to the component is obtained. Using this as an example, M target real-time stresses within a cycle are obtained. This application embodiment uses a strain fatigue damage prediction method based on the stress characteristics of the component, improving the accuracy of the fatigue damage prediction method.

[0111] Optionally, the method further includes:

[0112] Under certain preset conditions, the load is determined to be applied to the component for the first time. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

[0113] In the transfer case fatigue damage prediction method of this application embodiment, the gear change of the transmission refers to the change of starting gear (Parking, P), reverse gear (Reverse, R), neutral gear (Neutral, N), or drive gear (Drive, D), not the upshifting or downshifting within D gear. It should be noted that when the transmission gear changes, the component is definitely experiencing its first load; however, when the four-wheel drive gear corresponding to the component changes, it is sometimes necessary to consider changes in other transmission components to determine whether the component is experiencing its first load. Determining the load characteristics of the component is beneficial for accurately calculating the target applied stress value subsequently.

[0114] Optionally, when the calculation flag is a stress calculation flag, obtaining multiple first real-time stress values ​​of the components in the transfer case within a cycle includes:

[0115] Multiple sets of different parameter pairs are obtained, wherein each set of parameter pairs includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value.

[0116] Based on the multiple sets of different parameter pairs, a simulation model is established. The inputs of the simulation model include engine torque, transmission ratio, hydraulic torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration. The output of the simulation model includes the transfer case input torque.

[0117] Multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia, and multiple actual values ​​of transmission acceleration are input into the simulation model to determine the corresponding actual values ​​of multiple transfer case input torque.

[0118] Based on the actual input torque values ​​of the multiple transfer cases, the first real-time stress values ​​of the components in the transfer case within the cycle are determined.

[0119] In the component fatigue life prediction method of this application embodiment, a simulation model is established by obtaining multiple different parameter pairs during the testing phase. This model determines the correspondence between engine torque, transmission ratio, torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration, and the transfer case input torque. It should be noted that the input to the simulation model may include more than just engine torque, transmission ratio, torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration. A torque sensor is added to the component. The actual values ​​of engine torque, transmission ratio, torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration measured by the torque sensor are used to determine the actual value of the transfer case input torque through the simulation model.

[0120] The transfer case fatigue life prediction method of this application uses a simulation model established by multiple sets of different parameters obtained during the testing phase to determine the actual value of the real-time transfer case input torque, thereby determining the first real-time stress value and improving the accuracy of the transfer case fatigue life prediction method.

[0121] Optionally, the method further includes:

[0122] When the calculation flag is the strain calculation flag, obtain the H second transfer case input torque values ​​of the components in the transfer case within the cycle;

[0123] Calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case respectively;

[0124] Calculate H real-time stress values ​​based on the H real-time strain values ​​respectively;

[0125] Based on the H real-time stress values, calculate the second strain amplitude and the third average stress value;

[0126] Based on the second strain amplitude and the third average stress, the strain fatigue damage of the component during the cycle is predicted.

[0127] In the component fatigue life prediction method of this application embodiment, see also Figure 2 If the preset calculation flag is the strain calculation flag, the strain calculation process will proceed regardless of the stress characteristics of the component. However, it is necessary to distinguish between the first application of load to the component and multiple applications of load. For example, if it is the first application of load to the component, the first real-time strain value is calculated based on the input torque value of the second transfer case, and then the first real-time stress value is calculated based on the first real-time strain value. At this time, the first real-time stress value is saved. Then, the component is loaded a second time. At this time, the second real-time strain value is obtained based on the second input torque of the second transfer case, and combined with the first real-time strain value, the strain increment value compared to the first is obtained. Based on the strain increment value, the stress increment value is obtained. Then, based on the first real-time stress value and the stress increment value, the real-time stress value of the second application of load to the component is obtained. This embodiment of the application uses a strain fatigue damage prediction method based on the preset calculation flag, which is beneficial to meeting practical needs and thus improving the accuracy of fatigue damage prediction for components.

[0128] See Figure 3 , Figure 3 The third flowchart of the transfer case fatigue damage prediction method provided in this application embodiment describes a process where, when the control unit is powered on, it reads the historical cumulative damage values ​​of components from non-volatile memory and then calculates the fatigue damage within the current set cycle. The set cycle refers to the number of cycles required for processing, determined based on hardware performance. After the set cycle calculation is completed, the data is added to the historical cumulative damage values. If data reading is complete, meaning no new data is generated, the program waits for power-down; otherwise, it jumps to the beginning of the program. If data reading is incomplete, data is continuously read in and calculations are performed.

[0129] It should be noted that the above embodiment predicts fatigue damage by using real-time stress values. It can also predict fatigue damage by using strain values ​​based on the conversion relationship between real-time stress values ​​and strain values.

[0130] See Figure 4 , Figure 4 This is a structural diagram of a transfer case fatigue damage prediction device provided in another embodiment of this application.

[0131] like Figure 4 As shown, the transfer case fatigue damage prediction device 400 includes:

[0132] The first acquisition module 401 is used to acquire the calculation flag bit;

[0133] The second acquisition module 402 is used to acquire multiple first real-time stress values ​​of the components in the transfer case within the cycle when the calculation flag is a stress calculation flag.

[0134] The first prediction module 403 is used to predict stress fatigue damage of the component in the cycle when the plurality of first real-time stress values ​​include N second real-time stress values, wherein the second real-time stress values ​​are less than a set value and N is a positive integer.

[0135] The first modification module 404 is used to modify the calculation flag bit from the stress calculation flag bit to the strain calculation flag bit when the plurality of first real-time stress values ​​include M third real-time stress values, and the third real-time stress value is greater than the set value.

[0136] The second prediction module 405 is used to predict the strain fatigue damage of the component within the cycle based on the strain calculation flag, where M is a positive integer.

[0137] Optionally, the first prediction module includes:

[0138] The first calculation unit is used to calculate the stress amplitude and the average first stress of the component in the cycle period based on the N second real-time stress values ​​when the plurality of first real-time stress values ​​include N second real-time stress values.

[0139] The first prediction unit is used to predict stress fatigue damage of the component during the cycle based on the stress amplitude and the first average stress.

[0140] Optionally, the second prediction module includes:

[0141] The second calculation unit is used to calculate M target real-time strain values ​​based on the strain calculation flag bit and M first transfer case input torque values ​​respectively.

[0142] The third calculation unit is used to calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively;

[0143] The fourth calculation unit is used to calculate the first strain amplitude and the second average stress of the component within the cycle based on the M target real-time stress values.

[0144] The second prediction unit is used to predict the strain fatigue damage of the component during the cycle based on the first strain amplitude and the second average stress.

[0145] Optionally, the third computing unit includes:

[0146] The first determining subunit is used to determine the first target real-time stress value based on the acquired first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the first time, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the first time.

[0147] The first calculation subunit is used to calculate the first strain increment value based on the acquired second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, and K is a positive integer;

[0148] The second calculation subunit is used to calculate the first stress increment value based on the first strain increment value;

[0149] The third calculation subunit is used to calculate the third target real-time stress value based on the second target real-time stress value and the first stress increment value, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time.

[0150] The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

[0151] Optionally, the device further includes:

[0152] The first determining module is used to determine that a load is applied to the component for the first time when preset conditions are met. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

[0153] Optionally, the second acquisition module includes:

[0154] The first acquisition unit is used to acquire multiple sets of different parameter pairs, wherein each parameter pair includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value.

[0155] The first establishment unit is used to establish a simulation model based on the multiple sets of different parameter pairs. The inputs of the simulation model include engine torque, transmission speed ratio, hydraulic torque converter speed ratio, transfer case speed ratio, transmission efficiency, equivalent transmission inertia and transmission acceleration. The output of the simulation model includes transfer case input torque.

[0156] The first determining unit is used to input multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia and multiple actual values ​​of transmission acceleration into the simulation model, and to determine multiple actual values ​​of transfer case input torque accordingly.

[0157] The second determining unit is used to determine multiple first real-time stress values ​​of components in the transfer case within a cycle based on the actual values ​​of the input torque of the multiple transfer cases.

[0158] Optionally, the device further includes:

[0159] The third acquisition module is used to acquire H second transfer case input torque values ​​of the components in the transfer case within the cycle when the calculation flag is the strain calculation flag.

[0160] The first calculation module is used to calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case;

[0161] The second calculation module is used to calculate H real-time stress values ​​based on the H real-time strain values ​​respectively;

[0162] The third calculation module is used to calculate the second strain amplitude and the third average stress value based on the H real-time stress values.

[0163] The third prediction module is used to predict the strain fatigue damage of the component during the cycle based on the second strain amplitude and the third average stress.

[0164] See Figure 5 , Figure 5 This is a structural diagram of an electronic device provided in another embodiment of this application, such as... Figure 5As shown, the electronic device includes: a processor 501, a communication interface 502, a communication bus 504, and a memory 503, wherein the processor 501, the communication interface 502, and the memory 503 interact with each other through the communication bus 504.

[0165] The memory 503 stores the computer program; the processor 501 is used to acquire a calculation flag bit; when the calculation flag bit is a stress calculation flag bit, it acquires multiple first real-time stress values ​​of the components in the transfer case within a cycle; when the multiple first real-time stress values ​​include N second real-time stress values, it predicts stress fatigue damage of the components within the cycle, where the second real-time stress values ​​are less than a set value and N is a positive integer; when the multiple first real-time stress values ​​include M third real-time stress values, it modifies the calculation flag bit from a stress calculation flag bit to a strain calculation flag bit, where the third real-time stress values ​​are greater than the set value; based on the strain calculation flag bit, it predicts strain fatigue damage of the components within the cycle, where M is a positive integer.

[0166] Optionally, processor 501 is specifically used for:

[0167] When the plurality of first real-time stress values ​​include N second real-time stress values, the stress amplitude and the average first stress of the component within the cycle period are calculated based on the N second real-time stress values.

[0168] Based on the stress amplitude and the first average stress, the stress fatigue damage of the component during the cycle is predicted.

[0169] Optionally, processor 501 is specifically used for:

[0170] Based on the strain calculation flag, M target real-time strain values ​​are calculated according to M first transfer case input torque values ​​respectively;

[0171] Calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively;

[0172] Based on the M target real-time stress values, calculate the first strain amplitude and the second average stress value of the component within the cycle period;

[0173] Based on the first strain amplitude and the second average stress, the strain fatigue damage of the component during the cycle is predicted.

[0174] Optionally, processor 501 is specifically used for:

[0175] A first target real-time stress value is determined based on the obtained first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is first applied to the component, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is first applied to the component.

[0176] The first strain increment value is calculated based on the obtained second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, where K is a positive integer;

[0177] Calculate the first stress increment value based on the first strain increment value;

[0178] Based on the second target real-time stress value and the first stress increment value, a third target real-time stress value is calculated, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time.

[0179] The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

[0180] Optionally, processor 501 is also used for:

[0181] Under certain preset conditions, the load is determined to be applied to the component for the first time. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

[0182] Optionally, processor 501 is specifically used for:

[0183] Multiple sets of different parameter pairs are obtained, wherein each set of parameter pairs includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value.

[0184] Based on the multiple sets of different parameter pairs, a simulation model is established. The inputs of the simulation model include engine torque, transmission ratio, hydraulic torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration. The output of the simulation model includes the transfer case input torque.

[0185] Multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia, and multiple actual values ​​of transmission acceleration are input into the simulation model to determine the corresponding actual values ​​of multiple transfer case input torque.

[0186] Based on the actual input torque values ​​of the multiple transfer cases, the first real-time stress values ​​of the components in the transfer case within the cycle are determined.

[0187] Optionally, processor 501 is also used for:

[0188] When the calculation flag is the strain calculation flag, obtain the H second transfer case input torque values ​​of the components in the transfer case within the cycle;

[0189] Calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case respectively;

[0190] Calculate H real-time stress values ​​based on the H real-time strain values ​​respectively;

[0191] Based on the H real-time stress values, calculate the second strain amplitude and the third average stress value;

[0192] Based on the second strain amplitude and the third average stress, the strain fatigue damage of the component during the cycle is predicted.

[0193] The communication bus 504 mentioned in the above electronic device can be a Peripheral Component Interconnect (PCT) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus 504 can be divided into an address bus, a data bus, a control bus, etc. For ease of identification, it is represented by only one thick line in the figure, but this does not indicate that there is only one bus or one type of data.

[0194] Communication interface 502 is used for communication between the aforementioned terminal and other devices.

[0195] The memory 503 may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 503 may also be at least one storage device located remotely from the aforementioned processor 501. The aforementioned processor 501 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0196] This application also provides a computer-readable storage medium storing a computer program. When executed by a processor, this computer program implements the various processes of the above-described transfer case fatigue damage prediction method embodiments and achieves the same technical effects. To avoid repetition, it will not be described again here. The computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0197] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0198] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0199] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A method for predicting fatigue damage in a transfer case, characterized in that, The method includes: Get the calculation flag; When the calculation flag is the stress calculation flag, multiple first real-time stress values ​​of the components in the transfer case are obtained within the cycle. When the plurality of first real-time stress values ​​include N second real-time stress values, predict the stress fatigue damage of the component in the cycle, wherein the second real-time stress value is less than a set value, and N is a positive integer; When the plurality of first real-time stress values ​​include M third real-time stress values, the calculation flag is changed from a stress calculation flag to a strain calculation flag, and the third real-time stress value is greater than the set value; Based on the strain calculation flag, the strain fatigue damage of the component is predicted during the cycle, where M is a positive integer; The prediction of strain fatigue damage of the component within the cycle based on the strain calculation flag includes: Based on the strain calculation flag, M target real-time strain values ​​are calculated according to M first transfer case input torque values ​​respectively; Calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively; Based on the M target real-time stress values, calculate the first strain amplitude and the second average stress value of the component within the cycle period; Based on the first strain amplitude and the second average stress, predict the strain fatigue damage of the component during the cycle. The calculation of the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets includes: A first target real-time stress value is determined based on the obtained first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is first applied to the component, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is first applied to the component. The first strain increment value is calculated based on the obtained second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, where K is a positive integer; Calculate the first stress increment value based on the first strain increment value; Based on the second target real-time stress value and the first stress increment value, a third target real-time stress value is calculated, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time. The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

2. The fatigue damage prediction method of claim 1, wherein When the plurality of first real-time stress values ​​include N second real-time stress values, predicting the stress fatigue damage of the component during the cycle includes: When the plurality of first real-time stress values ​​include N second real-time stress values, the stress amplitude and the average first stress of the component within the cycle period are calculated based on the N second real-time stress values. Based on the stress amplitude and the first average stress, the stress fatigue damage of the component during the cycle is predicted.

3. The transfer case fatigue damage prediction method according to claim 1, characterized in that, The method further includes: Under certain preset conditions, the load is determined to be applied to the component for the first time. The preset conditions include at least one of the following: a change in transmission gear or a change in the four-wheel drive gear corresponding to the component.

4. The fatigue damage prediction method of claim 1, wherein When the calculation flag is a stress calculation flag, the method of obtaining multiple first real-time stress values ​​of the components in the transfer case within a cycle includes: Multiple sets of different parameter pairs are obtained, wherein each set of parameter pairs includes a first parameter and a second parameter corresponding to the first parameter. The first parameter includes engine torque test value, transmission speed ratio test value, hydraulic torque converter speed ratio test value, transfer case speed ratio test value, transmission efficiency test value, equivalent transmission inertia test value, and transmission acceleration test value. The second parameter includes transfer case input torque test value. Based on the multiple sets of different parameter pairs, a simulation model is established. The inputs of the simulation model include engine torque, transmission ratio, hydraulic torque converter ratio, transfer case ratio, transmission efficiency, equivalent transmission inertia, and transmission acceleration. The output of the simulation model includes the transfer case input torque. Multiple actual values ​​of engine torque, multiple actual values ​​of transmission speed ratio, multiple actual values ​​of hydraulic torque converter speed ratio, multiple actual values ​​of transfer case speed ratio, multiple actual values ​​of transmission efficiency, multiple actual values ​​of equivalent transmission inertia, and multiple actual values ​​of transmission acceleration are input into the simulation model to determine the corresponding actual values ​​of multiple transfer case input torque. Based on the actual input torque values ​​of the multiple transfer cases, the first real-time stress values ​​of the components in the transfer case within the cycle are determined.

5. The fatigue damage prediction method of claim 1, wherein The method further includes: When the calculation flag is the strain calculation flag, obtain the H second transfer case input torque values ​​of the components in the transfer case within the cycle; Calculate H real-time strain values ​​based on the H input torque values ​​of the second transfer case respectively; Calculate H real-time stress values ​​based on the H real-time strain values ​​respectively; Based on the H real-time stress values, calculate the second strain amplitude and the third average stress value; Based on the second strain amplitude and the third average stress, the strain fatigue damage of the component during the cycle is predicted.

6. A device for predicting fatigue damage of a transfer, characterized by comprising: The device includes: The first acquisition module is used to acquire the calculation flag bit; The second acquisition module is used to acquire multiple first real-time stress values ​​of the components in the transfer case within the cycle when the calculation flag is a stress calculation flag. The first prediction module is used to predict stress fatigue damage of the component in the cycle when the plurality of first real-time stress values ​​include N second real-time stress values, wherein the second real-time stress values ​​are less than a set value and N is a positive integer. The first modification module is used to modify the calculation flag bit from the stress calculation flag bit to the strain calculation flag bit when the plurality of first real-time stress values ​​include M third real-time stress values, and the third real-time stress value is greater than the set value; The second prediction module is used to predict the strain fatigue damage of the component within the cycle based on the strain calculation flag, where M is a positive integer; The second prediction module includes: The second calculation unit is used to calculate M target real-time strain values ​​based on the strain calculation flag bit and M first transfer case input torque values ​​respectively. The third calculation unit is used to calculate the real-time stress values ​​of the M targets based on the real-time strain values ​​of the M targets respectively; The fourth calculation unit is used to calculate the first strain amplitude and the second average stress of the component within the cycle based on the M target real-time stress values. The second prediction unit is used to predict the strain fatigue damage of the component during the cycle based on the first strain amplitude and the second average stress. The third computing unit includes: The first determining subunit is used to determine the first target real-time stress value based on the acquired first target real-time strain value, wherein the first target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the first time, and the first target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the first time. The first calculation subunit is used to calculate the first strain increment value based on the acquired second target real-time strain value and third target real-time strain value, wherein the second target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the Kth time, and the third target real-time strain value is the target real-time strain value of the component when the load is applied to the component for the K+1th time, and K is a positive integer; The second calculation subunit is used to calculate the first stress increment value based on the first strain increment value; The third calculation subunit is used to calculate the third target real-time stress value based on the second target real-time stress value and the first stress increment value, wherein the second target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the Kth time, and the third target real-time stress value is the target real-time stress value of the component calculated when the load is applied to the component for the K+1th time. The M target real-time stress values ​​include the first target real-time stress value and the third target real-time stress value.

7. An electronic device, comprising: It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the transfer case fatigue damage prediction method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the transfer case fatigue damage prediction method as described in any one of claims 1 to 5.

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