Transmission chain accelerated fatigue test load spectrum determination method and device

Abstract

The invention provides a transmission chain accelerated fatigue test load spectrum determination method and device, and belongs to the field of wind generating sets. The method comprises the steps of obtaining a transmission chain design fatigue load; combining the transmission chain design fatigue load to a preset number of load grades; determining a conversion load and a conversion rotating speed of each load grade according to an equivalent fatigue damage principle; and strengthening the conversion load and the conversion rotating speed of each load grade to obtain an accelerated fatigue test load spectrum. According to the method, equivalent processing is carried out on a transmission chain design fatigue load according to an equivalent fatigue damage principle, so that the transmission chain design fatigue load is converted into limited several groups of loads, and an accelerated fatigue test load spectrum is formed and used for guiding design of a transmission chain accelerated fatigue test working condition.

Description

Technical Field

[0001] The invention relates to the field of wind turbine generator sets, and in particular to a method for determining a load spectrum of an accelerated fatigue test of a transmission chain and a device for determining a load spectrum of an accelerated fatigue test of a transmission chain. Background Art

[0002] At present, fatigue tests for evaluating the durability performance of key components of wind turbines are usually carried out at the component subsystem level. For example, gearboxes, main bearings, pitch bearings and blades are required to undergo fatigue tests on prototype components in order to obtain design certification to verify the reliability of the model. The test equipment and test schemes used for fatigue tests at the above-mentioned component levels are relatively mature.

[0003] In recent years, many complete machine manufacturers at home and abroad have built full-size cabin ground test benches for accelerated fatigue testing of transmission chains, simulating the loads that the power transmission system components of the unit will bear during their 20-year lifespan within a few months. Compared with traditional fatigue testing methods, accelerated life testing can not only shorten the required testing time, but also reduce testing costs. However, due to the differences in the load loading methods of the test benches, the current component-level fatigue test scheme cannot be directly applied to the transmission chain fatigue test. There is also a lack of standards and literature on the load processing methods for the transmission chain accelerated fatigue test to guide the design of the transmission chain accelerated fatigue test conditions.

[0004] The design fatigue load of each component of the transmission chain is generally given in the form of load duration distribution (LDD, Load Duration Distribution), which is used for fatigue load verification of components. The design fatigue load of the transmission chain takes the hub center as the coordinate origin and includes forces and moments in six directions: Mx, My, Mz, Fx, Fy and Fz. Due to the large amount of LDD load data, which generally includes hundreds of load levels and their duration, it cannot be directly used for testing. Summary of the invention

[0005] The purpose of an embodiment of the present invention is to provide a method and device for determining a load spectrum of an accelerated fatigue test of a transmission chain. The method performs equivalent processing on the design fatigue load of the transmission chain according to the principle of equivalent fatigue damage, converts it into a limited number of groups of loads, and forms an accelerated fatigue test load spectrum, which is used to guide the design of accelerated fatigue test conditions of the transmission chain.

[0006] In order to achieve the above object, the present invention provides a method for determining a load spectrum of a transmission chain accelerated fatigue test in a first aspect, the method comprising: Obtain the transmission chain design fatigue load; combining the drive chain design fatigue loads into a preset number of load levels; Determine the conversion load and conversion speed for each load level based on the equivalent fatigue damage principle; The conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum.

[0007] In some feasible embodiments, the transmission chain design fatigue load is combined into a preset number of load levels, including: In the case that the designed fatigue load of the transmission chain is distributed only in the positive direction or only in the negative direction, the designed fatigue load of the transmission chain is evenly divided into a preset number of intervals, and one of the intervals represents a load level.

[0008] In some feasible embodiments, the transmission chain design fatigue load is combined into a preset number of load levels, including: In the case where the transmission chain design fatigue load is distributed in both the positive direction and the negative direction, the data of the transmission chain design fatigue load in the positive direction is divided into a first number of intervals, and the data of the transmission chain design fatigue load in the negative direction is divided into a second number of intervals, one of the intervals represents a load level, and the sum of the first number and the second number is equal to a preset number.

[0009] In some feasible embodiments, determining the conversion load and conversion speed of each load level according to the equivalent fatigue damage principle includes: According to the transmission chain design fatigue load in each load level, determine the middle value of the corresponding load level as the conversion load; Determine a first load intensification factor corresponding to the design fatigue load according to each design fatigue load in the load level and a conversion load corresponding to the load level; Determining a first time reduction ratio corresponding to the design fatigue load according to a first load strengthening factor and a material factor corresponding to the design fatigue load; Determining a conversion speed corresponding to the design fatigue load according to the first time reduction ratio and the original speed corresponding to the design fatigue load; The sum of the conversion speeds of the design fatigue loads in each load level is calculated to obtain the conversion speed of the corresponding load level.

[0010] In some feasible embodiments, the conversion load and conversion speed of each load level are strengthened to obtain an accelerated fatigue test load spectrum, including: Calculate the target total speed for the target days based on the rated speed; Calculate the total conversion speed based on the conversion speed of each load level; Calculating a total speed reduction ratio according to the target total speed and the converted total speed, wherein the total speed reduction ratio is equal to the total time reduction ratio; Calculate the average load intensification factor based on the total time reduction ratio and material factor; Determine the second reinforcement factor of each load level and the first load after reinforcement according to the average load reinforcement factor and the conversion load of each load level; Calculate the second time reduction ratio of the corresponding load level according to the second strengthening coefficient and material coefficient of each load level; Calculate the first speed after load intensification according to the second time reduction ratio and the conversion speed of each load level; Calculate the first loading time corresponding to each load level according to the first speed and the rated speed; Calculating a first total loading speed and a first total loading time according to the first speed and the first loading time of each load level; Determining whether the test time requirement is met according to the first total loading speed and the first total loading time; Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the first load and the first rotation speed.

[0011] In some feasible embodiments, determining the second reinforcement coefficient of each load level and the reinforced first load according to the average load reinforcement coefficient and the conversion load of each load level includes: Calculate the initial intensification load for each load level based on the average load intensification factor and the conversion load for each load level; Determining whether the initial enhanced load of each load level exceeds a first load threshold; If it exceeds, the reinforcement coefficient of the corresponding load level is adjusted to a preset multiple of the average load reinforcement coefficient, and the initial reinforcement load is recalculated until the reinforcement load of the corresponding load level does not exceed the first load threshold; The initial intensified load that does not exceed the load threshold and the corresponding load intensification factor are used as the second intensification factor and the first load of the corresponding load level.

[0012] In some feasible embodiments, when the test time requirement is not met, the method further includes: According to the first load of each load level, determining a target load level where the first load is less than a second load threshold; Adjust the second reinforcement factor of the target load level to the fourth reinforcement factor; The first load, total loading speed and total loading time are recalculated according to the fourth strengthening coefficient to determine whether the test requirements are met.

[0013] In some feasible embodiments, the conversion load and conversion speed of each load level are strengthened to obtain an accelerated fatigue test load spectrum, including: Determining the enhanced target load in different distribution directions of the design fatigue load according to the first preset load; Calculate the fifth reinforcement factor for each load level based on the target load and the conversion load; Calculate the third time reduction ratio corresponding to the load level according to the fifth strengthening coefficient and the material coefficient; Calculate the second speed after load intensification according to the third time reduction ratio and the conversion speed of each load level; Calculate the second loading time corresponding to each load level according to the second speed and the rated speed; Calculate a second total loading speed and a second total loading time according to the second speed and the second loading time of each load level; Judging whether the test time requirement is met according to the second total loading speed and the second total loading time; Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the target load and the second rotation speed.

[0014] In some feasible embodiments, before constructing the accelerated fatigue test load spectrum, the method further includes: The load data for constructing the accelerated fatigue test load spectrum is rounded up to the hundredth place to obtain the first equivalent load; Calculate the equivalent speed according to the first equivalent load; The accelerated fatigue test load spectrum is constructed according to the first equivalent load and equivalent speed.

[0015] A second aspect of the present application provides a device for determining a load spectrum of a transmission chain accelerated fatigue test, the device comprising: A data acquisition unit, used to obtain the design fatigue load of the transmission chain; A load merging unit, used to merge the transmission chain design fatigue load into a preset number of load levels; A calculation unit for determining a conversion load and a conversion speed for each load level according to an equivalent fatigue damage principle; The load spectrum generating unit is used to strengthen the conversion load and conversion speed of each load level to obtain the accelerated fatigue test load spectrum.

[0016] Through the above technical scheme, hundreds of transmission chain design fatigue loads are equivalently processed according to the principle of equivalent fatigue damage, so that they are converted into a limited number of loads to form an accelerated fatigue test load spectrum, which is used to guide the design of transmission chain accelerated fatigue test conditions. The loads in the accelerated fatigue test load spectrum are used as the loads for the transmission chain accelerated fatigue test. By strengthening the combined loads, the total test time can be controlled, the purpose of accelerated fatigue verification can be achieved, the test efficiency is improved, and the test cost is reduced.

[0017] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings: Figure 1 It is a flow chart of a method for determining a load spectrum of a transmission chain accelerated fatigue test provided by one embodiment of the present invention; Figure 2 This is a method and steps for determining a load spectrum of a transmission chain accelerated fatigue test provided by an embodiment of the present invention; Figure 3 This is an example of a merging interval process provided by an embodiment of the present invention; Figure 4 It is an example of strengthening results provided by a linear strengthening method according to an embodiment of the present invention; Figure 5 This is an example of strengthening results provided by one embodiment of the present invention using a method of applying a primary load for strengthening; Figure 6 It is a block diagram of a device for determining a load spectrum of a transmission chain accelerated fatigue test provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0019] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0020] In this application, the load is converted according to the fatigue damage principle, which is as follows: According to the Minner criterion, the total damage degree of a part is equal to the cumulative sum of the ratio of the number of cycles in actual operation under each level of stress to the number of cycles on the S / N curve under the corresponding first level of stress. Therefore, it can be expressed as:

[0021] Where: D represents the total fatigue damage degree of the parts; n i Indicates the number of cycles when actually working under the i-th level stress; N i Represents the number of cycles on the S / N curve under the i-th stress level.

[0022] Whether a part has suffered fatigue failure depends on whether the damage degree D is less than 1. When the damage degree D ≥ 1, it means that the part has suffered fatigue failure.

[0023] The formula for single-stage equivalent load given by standard ISO:6336-6 is as follows:

[0024] According to the equivalent fatigue damage theory, when the unit is working under a load of M i Under the action of torque n i The damage amount produced by the number of cycles can be equivalent to that produced by the load M j Under the action of torque n j The amount of damage produced by the number of cycles. Where p is the slope of the S / N curve, which is related to the material.

[0025] Therefore, according to the above formula, when the load is M1, M2…M i Under the action of torque n1, n2…n i The damage amount produced by the number of cycles can be equivalent to that produced by the load M i+1 Under the action of torque The amount of damage caused by the number of cycles.

[0026]

[0027] Convert the number of loops n into a time reduction ratio m, Converted to load increase ratio k, the relationship between time reduction ratio m and load increase ratio k is obtained: .

[0028] Figure 1 FIG. 1 is a flow chart of a method for determining a load spectrum of a transmission chain accelerated fatigue test provided by an embodiment of the present invention. Figure 1 As shown, an embodiment of the present invention provides a method for determining a load spectrum of a transmission chain accelerated fatigue test, the method comprising: S1: Obtain the design fatigue load of the transmission chain.

[0029] S2: Combining the transmission chain design fatigue load into a preset number of load levels.

[0030] S3: Determine the conversion load and conversion speed for each load level based on the equivalent fatigue damage principle.

[0031] S4: Strengthen the conversion load and conversion speed of each load level to obtain the accelerated fatigue test load spectrum.

[0032] According to the equivalent fatigue damage principle, the design fatigue load of the transmission chain is equivalently processed and converted into a limited number of load groups to form an accelerated fatigue test load spectrum, which is used to guide the design of the accelerated fatigue test conditions of the transmission chain.

[0033] The fatigue load of the transmission chain design may be distributed entirely in the positive direction, entirely in the negative direction, or in both the positive and negative directions, depending on the direction of the force.

[0034] In some possible embodiments, Figure 2 As shown, for the case where the transmission chain design fatigue load is all distributed in the positive direction or all distributed in the negative direction, the transmission chain design fatigue load is merged into a preset number of load levels, including: In the case where the transmission chain design fatigue load is distributed only in the positive direction or only in the negative direction, the transmission chain design fatigue load is evenly divided into a preset number of intervals, and one of the intervals represents a load level. The preset number is set according to demand. In a feasible embodiment, the preset number can be 10. For example, assuming that there are 120 transmission chain design fatigue loads, divided into 10 intervals, each interval has 12 design fatigue loads, that is, the first to twelfth design fatigue loads are used as the first interval, the thirteenth to twenty-fourth design fatigue loads are used as the second interval, and so on.

[0035] In practical applications, the number of design fatigue loads may not be an integer multiple of the preset number. In this case, the quotient and remainder of the preset number are calculated based on the number of design fatigue loads; it is necessary to divide the design fatigue loads that are one more than the quotient in the interval of the remainder number, and divide the design fatigue loads in other intervals according to the number of quotients. For example, assuming that there are 123 transmission chain design fatigue loads, divided into 10 intervals, 123÷10=12 remainder 3, then, it is necessary to divide 12+1=13 design fatigue loads in 3 intervals, and divide 12 design fatigue loads in the remaining 7 intervals.

[0036] In some other feasible embodiments, when the transmission chain design fatigue load is distributed in both positive and negative directions, the transmission chain design fatigue load is combined into a preset number of load levels, including: In the case where the transmission chain design fatigue load is distributed in both the positive and negative directions, the data of the transmission chain design fatigue load in the positive direction is divided into a first number of intervals, and the data of the transmission chain design fatigue load in the negative direction is divided into a second number of intervals, one of the intervals represents a load level, and the sum of the first number and the second number is equal to a preset number. The preset number is set according to demand, and in a feasible embodiment, the preset number can be 10. For example, assuming that there are 120 transmission chain design fatigue loads, 24 of which are distributed in the negative direction and 96 are distributed in the positive direction, the 24 negative direction design fatigue loads can be divided into 2 intervals, and the 96 positive direction design fatigue loads can be divided into 8 intervals, with 10 in each interval.

[0037] In practical applications, the number of design fatigue loads may not be an integer multiple of the preset number. In this case, it is necessary to make a roughly even division according to the number distributed in each direction. For example, assuming that there are 145 design fatigue loads for the transmission chain, 45 design fatigue loads are distributed in the negative direction, and 100 design fatigue loads are distributed in the positive direction, then the design fatigue loads in the negative direction can be divided into 3 intervals, with 15 design fatigue loads in each interval, and the positive direction can be divided into 7 intervals, of which 2 intervals have 15 design fatigue loads and 5 intervals have 14 design fatigue loads.

[0038] After the intervals are divided, the conversion load and conversion speed of each load level need to be determined according to the equivalent fatigue damage principle. Figure 3 As shown, the conversion load and conversion speed of each load level are determined according to the equivalent fatigue damage principle, including: According to the transmission chain design fatigue load in each load level, determine the middle value of the corresponding load level as the conversion load; According to each design fatigue load in the load level and the conversion load of the corresponding load level, the first load enhancement factor corresponding to the design fatigue load is determined. In the embodiment of the present application, the conversion load and the design fatigue load are calculated. The ratio of the first load intensification factor corresponding to the design fatigue load is obtained. .

[0039] ; Where i=1,2,..., represents the i-th design fatigue load, Indicates the conversion load of the load level where the design load is located. In the above embodiment including 10 intervals, .

[0040] Determine the first time reduction ratio of the corresponding design fatigue load according to the first load reinforcement factor and material coefficient p of the corresponding design fatigue load : ; Where p is the material coefficient and is the slope of the S / N curve.

[0041] According to the first time reduction ratio and the original speed corresponding to the design fatigue load , determine the conversion speed corresponding to the design fatigue load : .

[0042] Calculate the sum of the conversion speeds of the design fatigue loads in each load level to obtain the conversion speed of the corresponding load level. Assuming that the interval corresponding to the first load level contains 10 design fatigue loads, you need to calculate , , ..., The sum of the conversion speed of the first load level is obtained, which is expressed as , the conversion speed of the second load level is expressed as ,in, a 1 ，a 2 ，a 3 ，a 4 ，a 5 ，a 6 ，a 7 ，a 8 ，a 9 ，a 10 indicates the corresponding load level; other load levels are similar.

[0043] After obtaining the conversion load and the conversion speed, the conversion load and the conversion speed need to be strengthened. In the embodiment of the present application, a linear strengthening method or a primary load loading strengthening method can be used.

[0044] For the linear strengthening method, the conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum, including: The target total speed for the target number of days is calculated based on the rated speed. In one feasible embodiment, the target number of days is 30 days. GoalTotal The calculation formula is as follows: Revs GoalTotal =n rated *30*24*60; Among them, n rated is the rated speed in rpm.

[0045] According to the conversion speed of each load level, the total conversion speed is calculated. In the embodiment of the present application, the conversion speed of each load level is added to obtain the total conversion speed.

[0046] The total speed reduction ratio is calculated according to the target total speed and the converted total speed, and the total speed reduction ratio is equal to the total time reduction ratio m. total In the embodiment of the present application, the total speed reduction ratio is obtained by dividing the target total speed by the conversion total speed.

[0047] Reduce the proportion m according to the total time total and material factor p to calculate the average load intensification factor k avg In the embodiment of the present application, the average load intensification factor is calculated according to the equivalent fatigue damage principle: .

[0048] According to the average load reinforcement factor k avg And the conversion loads for each load level Determination of the second reinforcement factor k for each load level 2i and the first load after strengthening M k2i ; The second reinforcement factor k according to the load level 2i and material coefficient p to calculate the second time reduction ratio m corresponding to the load level 2i ; The second time reduction ratio m according to each load level 2i The first speed after load strengthening is calculated by converting the speed. The calculation formula is as follows: ; in, represents the first speed of the i-th load level, represents the conversion speed of the i-th sum level, m 2i Represents the second time reduction ratio of the i-th load level, where i=1,2,...10.

[0049] According to the first speed and the rated speed n rated Calculate the first loading time T corresponding to each load level 1i : T 1i =Revs Goalai / 60*n rated .

[0050] According to the first speed and the first loading time of each load level, the first total loading speed and the first total loading time are calculated. The first speeds of each load level are summed to obtain the first total loading speed, and the first loading times are summed to obtain the first total loading time.

[0051] Whether the test time requirement is met is determined based on the first total loading speed and the first total loading time. Generally, the total loading time needs to be shortened to a few months to shorten the experimental cycle. Therefore, the test time can be set according to the design period requirements.

[0052] Under the condition that the test time requirements are met, the accelerated fatigue test load spectrum is constructed according to the target load and the first speed. According to the above technical means, by strengthening the combined load, the total test time is controlled to within a few months, the test efficiency is improved, the test cost is reduced, the purpose of accelerated fatigue verification can be achieved, and the unit design cycle can be shortened.

[0053] In some feasible embodiments, determining the second reinforcement coefficient of each load level and the reinforced first load according to the average load reinforcement coefficient and the conversion load of each load level includes: Calculate the initial intensification load for each load level based on the average load intensification factor and the conversion load for each load level M kavg .

[0054] M kavg =M goali *k avg ; It is determined whether the initial strengthening load of each load level exceeds the first load threshold. Generally, the first load threshold is 0.9 times the ultimate load.

[0055] If it exceeds, the reinforcement factor of the corresponding load level is adjusted to a preset multiple of the average load reinforcement factor, for example, it can be adjusted to 0.9 k avg ; Recalculate the initial enhanced load until the enhanced load corresponding to the load level does not exceed the first load threshold; The initial enhanced load and the corresponding load enhancement factor that do not exceed the load threshold are used as the second enhancement factor and the first load of the corresponding load level. For example, if the initial enhanced load calculated according to the average load enhancement factor for the first load level is less than 0.9 times the limit load, then the second enhancement factor of the first load level is equal to the average load enhancement factor, and the first load is equal to the initial enhancement load; if the initial enhanced load calculated according to the average load enhancement factor for the second load level is greater than 0.9 times the limit load, then the enhancement factor is adjusted to 0.9 k avg After that, the calculated initial strengthening load is 0.86 times the ultimate load, which is less than 0.9 times the ultimate load. Therefore, the second load level factor is equal to 0.9 k avg , the first load is equal to 0.86 times the limit load. Through the above adjustment, by controlling the initial strengthening load not to exceed the first load threshold, it can be ensured that the test piece will not be overloaded and damaged during the test process, and the test can be completed.

[0056] In some feasible embodiments, when the test time requirement is not met, the method further includes: According to the first load of each load level, a target load level in which the first load is less than a second load threshold is determined. Generally, the second load threshold may be 0.5 times the limit load.

[0057] The second strengthening factor for adjusting the target load level is the fourth strengthening factor. In some feasible embodiments, the second strengthening factor can be increased, and the specific increase is determined according to the difference between the calculated first total loading time and the experimental time and the difference between the corresponding first load and the second load threshold. For example, if the first total loading time exceeds the experimental time by a large amount, the second strengthening factor may need to be increased by a large amount to further shorten the time; for another example, if the difference between the first load and the second load threshold is large, the corresponding load level has a large margin for adjustment, allowing the second strengthening factor to be increased by a large amount.

[0058] The first load, total loading speed and total loading time are recalculated according to the fourth reinforcement coefficient to determine whether the test requirements are met. The method for calculating the total loading speed and total loading time is the same as described above and will not be repeated here.

[0059] According to the above adjustment process, the test time can be shortened according to the test requirements to improve the test efficiency while ensuring that the loads of each load level do not exceed the safety threshold.

[0060] Figure 4 An example of strengthening results using the linear strengthening method when the design fatigue load is distributed only in the positive direction is given. If the design fatigue load is distributed in both the positive and negative directions, the strengthening method using the linear strengthening method is the same and will not be repeated here.

[0061] In order to facilitate load loading in the test, in some feasible embodiments, before constructing the accelerated fatigue test load spectrum, the method further includes: The load data for constructing the accelerated fatigue test load spectrum is rounded up to the hundredth place to obtain the first equivalent load. For example, the first load of a load level determined by the above method is 4523 kNm, which is rounded up to 4600 kNm.

[0062] The equivalent speed is calculated according to the first equivalent load. Specifically, the corresponding load enhancement factor is first calculated according to the first equivalent load and the converted load, and then the equivalent speed is calculated according to the enhancement factor and the converted speed.

[0063] Finally, the load spectrum of the accelerated fatigue test is constructed according to the first equivalent load and equivalent speed. In the test process, integer loads are easier to load and control.

[0064] For the primary load strengthening method, the conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum, including: The enhanced target load in different distribution directions of the design fatigue load is determined according to the first preset load. In some feasible embodiments, the target load may be limited to no more than 0.9 times the ultimate load.

[0065] The fifth reinforcement factor for each load level is calculated based on the target load and the converted load.

[0066] The third time reduction ratio corresponding to the load level is calculated according to the fifth strengthening coefficient and the material coefficient.

[0067] The second speed after load intensification is calculated according to the third time reduction ratio of each load level and the conversion speed. The second speed calculation formula is the same as the aforementioned first speed calculation formula.

[0068] The second loading time corresponding to each load level is calculated according to the second speed and the rated speed, and the calculation formula of the second loading time is the same as the calculation formula of the first loading time.

[0069] According to the second rotation speed and the second loading time of each load level, the second total loading rotation speed and the second total loading time are calculated; the second rotation speeds of each load level are summed to obtain the second total loading rotation speed, and the second loading times are summed to obtain the second total loading time.

[0070] Whether the test time requirement is met is determined based on the second total loading speed and the second total loading time. Generally, the total loading time needs to be shortened to a few months to shorten the experimental cycle. Therefore, the test time can be set according to the design period requirements.

[0071] Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the target load and the second speed. In some feasible embodiments, the second speeds of the covered load levels are summed according to the load levels covered by the target load to obtain the speed corresponding to the accelerated fatigue test load spectrum.

[0072] According to the above-mentioned technical means, by strengthening the combined load, the total test time can be controlled within a few months, thereby improving the test efficiency and reducing the test cost, achieving the purpose of accelerating fatigue verification and shortening the unit design cycle.

[0073] It should be noted that for the design fatigue load distributed only in the positive direction or only in the negative direction, there is only one load level after strengthening using the first-level load strengthening method. At this time, the load corresponding to the accelerated fatigue test load spectrum is the sum of the second speeds of the 10 load levels.

[0074] For design fatigue loads distributed in both positive and negative directions, such as Figure 5As shown, when determining the target load according to the first preset load, it is necessary to determine the target load in different directions. Specifically, the first target load after strengthening in the positive direction and the second target load after strengthening in the negative direction are determined according to the first preset load. In some feasible embodiments, the two strengthened target loads M in the positive and negative directions can be selected with a limit of no more than 0.9 times the limit load. k+ and M k- .

[0075] The fifth reinforcement coefficient of each load level is calculated according to the first target load, the second target load and the conversion load. For the load level in the positive direction, the first target load is divided by the corresponding conversion load to obtain the fifth reinforcement coefficient of the corresponding load level. For the load level in the negative direction, the second target load is divided by the corresponding conversion load to obtain the fifth reinforcement coefficient of the corresponding load level.

[0076] According to the fifth reinforcement coefficient k 5i And the material coefficient p calculates the third time reduction ratio M corresponding to the load level 3i : M 3i =1 / (k 5i ^p).

[0077] The second speed after load intensification is calculated according to the third time reduction ratio of each load level and the conversion speed; the calculation formula of the second speed is the same as the aforementioned calculation formula of the first speed.

[0078] The second loading time corresponding to each load level is calculated according to the second speed and the rated speed, and the calculation formula of the second loading time is the same as the calculation formula of the first loading time.

[0079] According to the second rotation speed and the second loading time of each load level, the second total loading rotation speed and the second total loading time are calculated; the second rotation speeds of each load level are summed to obtain the second total loading rotation speed, and the second loading times are summed to obtain the second total loading time.

[0080] Whether the test time requirement is met is determined based on the second total loading speed and the second total loading time. Generally, the total loading time needs to be shortened to a few months to shorten the experimental cycle. Therefore, the test time can be set according to the design period requirements.

[0081] Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the first target load, the second target load and the second rotational speed. In some feasible embodiments, the second rotational speeds of the covered load levels are summed according to the load levels covered by the first target load to obtain the rotational speed corresponding to the first target load in the accelerated fatigue test load spectrum, and the second rotational speeds of the covered load levels are summed according to the load levels covered by the second target load to obtain the rotational speed corresponding to the second target load in the accelerated fatigue test load spectrum.

[0082] According to the above-mentioned technical means, by strengthening the combined load, the total test time can be controlled within a few months, thereby improving the test efficiency and reducing the test cost, achieving the purpose of accelerating fatigue verification and shortening the unit design cycle.

[0083] For the design fatigue load distributed in both the positive and negative directions, the load level after strengthening by the first-level load strengthening method includes two sections. It is assumed that there are 3 load levels (first, second, and third) in the negative direction, and the target load is Ms-; there are 7 load levels (fourth to tenth) in the positive direction, and the target load is Ms+; then the second speeds corresponding to the first to third load levels need to be added together as the speed corresponding to Ms- in the accelerated fatigue test load spectrum; the second speeds corresponding to the fourth to tenth load levels need to be added together as the speed corresponding to Ms+ in the accelerated fatigue test load spectrum.

[0084] In some feasible embodiments, when the test time requirement is not met, the method further includes: The first target load and the second target load are increased based on the standard of not exceeding the first preset load, and the second total loading speed and the second total loading time are recalculated to determine whether the test time requirements are met. While ensuring that the loads of each load level do not exceed the safety threshold, the test time can be shortened according to the test requirements to improve the test efficiency.

[0085] In some feasible embodiments, in order to facilitate load loading in the test, before constructing the accelerated fatigue test load spectrum, the method further includes: The load data for constructing the accelerated fatigue test load spectrum is rounded up to the hundredth place to obtain the first equivalent load; for example, the first target load of a certain load level determined by the above method is 4523 kNm, which is rounded up to the hundredth place to 4600 kNm.

[0086] The equivalent speed is calculated according to the first equivalent load. Specifically, the corresponding load enhancement factor is first calculated according to the first equivalent load and the converted load, and then the equivalent speed is calculated according to the enhancement factor and the converted speed.

[0087] Finally, the load spectrum of the accelerated fatigue test is constructed according to the first equivalent load and equivalent speed. In the test process, integer loads are easier to load and control.

[0088] The second aspect of the present application provides a device for determining a load spectrum of a transmission chain accelerated fatigue test, such as Figure 6 As shown, the device comprises: A data acquisition unit, used to obtain the design fatigue load of the transmission chain; A load merging unit, used to merge the transmission chain design fatigue load into a preset number of load levels; A calculation unit for determining a conversion load and a conversion speed for each load level according to an equivalent fatigue damage principle; The load spectrum generating unit is used to strengthen the conversion load and conversion speed of each load level to obtain the accelerated fatigue test load spectrum.

[0089] The method of the present application mainly includes two steps: design load level merging and load strengthening. This method can be used to convert hundreds of design load levels into a limited number of load levels and duration conditions, which are used to load the load of the transmission chain accelerated fatigue test; and by strengthening the merged load, the total test time is controlled to within a few months, which improves the test efficiency and reduces the test cost. Through the method of the present invention, the purpose of accelerated fatigue verification can be achieved, the reliability and durability of the power transmission system of the wind turbine can be evaluated, and the test results can also be used to verify the design method and model, further verify the performance and reliability of the wind turbine, and reduce the design and quality problems of the unit caused.

[0090] Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0091] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0092] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims

1. A method for determining a load spectrum of a transmission chain accelerated fatigue test, characterized in that: The method comprises: Obtain the transmission chain design fatigue load; combining the drive chain design fatigue loads into a preset number of load levels; Determine the conversion load and conversion speed for each load level based on the equivalent fatigue damage principle; The conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum.

2. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 1, characterized in that: Combine the drive train design fatigue loads into a pre-set number of load levels, including: In the case that the designed fatigue load of the transmission chain is distributed only in the positive direction or only in the negative direction, the designed fatigue load of the transmission chain is evenly divided into a preset number of intervals, and one of the intervals represents a load level.

3. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 1, characterized in that: Combine the drive train design fatigue loads into a pre-set number of load levels, including: In the case where the transmission chain design fatigue load is distributed in both the positive and negative directions, the data in the positive direction of the transmission chain design fatigue load is divided into a first number of intervals, and the data in the negative direction of the transmission chain design fatigue load is divided into a second number of intervals, one of the intervals represents a load level, and the sum of the first number and the second number is equal to a preset number.

4. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 1, characterized in that: The determination of the conversion load and conversion speed of each load level according to the equivalent fatigue damage principle includes: According to the transmission chain design fatigue load in each load level, determine the middle value of the corresponding load level as the conversion load; Determine a first load intensification factor corresponding to the design fatigue load according to each design fatigue load in the load level and a conversion load corresponding to the load level; Determining a first time reduction ratio corresponding to the design fatigue load according to a first load strengthening factor and a material factor corresponding to the design fatigue load; Determining a conversion speed corresponding to the design fatigue load according to the first time reduction ratio and the original speed corresponding to the design fatigue load; The sum of the conversion speeds of the design fatigue loads in each load level is calculated to obtain the conversion speed of the corresponding load level.

5. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 1, characterized in that: The conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum, including: Calculate the target total speed for the target days based on the rated speed; Calculate the total conversion speed based on the conversion speed of each load level; Calculating a total speed reduction ratio according to the target total speed and the converted total speed, wherein the total speed reduction ratio is equal to the total time reduction ratio; Calculate the average load intensification factor based on the total time reduction ratio and material factor; Determine the second reinforcement factor of each load level and the first load after reinforcement according to the average load reinforcement factor and the conversion load of each load level; Calculate the second time reduction ratio of the corresponding load level according to the second strengthening coefficient and material coefficient of each load level; Calculate the first speed after load intensification according to the second time reduction ratio and the conversion speed of each load level; Calculate the first loading time corresponding to each load level according to the first speed and the rated speed; Calculating a first total loading speed and a first total loading time according to the first speed and the first loading time of each load level; Determining whether the test time requirement is met according to the first total loading speed and the first total loading time; Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the first load and the first rotation speed.

6. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 5, characterized in that: The second reinforcement coefficient of each load level and the first load after reinforcement are determined according to the average load reinforcement coefficient and the conversion load of each load level, including: Calculate the initial intensification load for each load level based on the average load intensification factor and the conversion load for each load level; Determining whether the initial enhanced load of each load level exceeds a first load threshold; If it exceeds, the reinforcement coefficient of the corresponding load level is adjusted to a preset multiple of the average load reinforcement coefficient, and the initial reinforcement load is recalculated until the reinforcement load of the corresponding load level does not exceed the first load threshold; The initial intensified load that does not exceed the load threshold and the corresponding load intensification factor are used as the second intensification factor and the first load of the corresponding load level.

7. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 5, characterized in that: In the event that the test time requirement is not met, the method further comprises: According to the first load of each load level, determining a target load level where the first load is less than a second load threshold; Adjust the second reinforcement factor of the target load level to the fourth reinforcement factor; The first load, total loading speed and total loading time are recalculated according to the fourth strengthening coefficient to determine whether the test requirements are met.

8. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 1, characterized in that: The conversion load and conversion speed of each load level are strengthened to obtain the accelerated fatigue test load spectrum, including: Determining the enhanced target loads in different distribution directions of the designed fatigue load according to the first preset load; Calculate the fifth reinforcement factor for each load level based on the target load and the conversion load; Calculate the third time reduction ratio corresponding to the load level according to the fifth strengthening coefficient and the material coefficient; Calculate the second speed after load intensification according to the third time reduction ratio and the conversion speed of each load level; Calculate the second loading time corresponding to each load level according to the second speed and the rated speed; Calculate a second total loading speed and a second total loading time according to the second speed and the second loading time of each load level; Judging whether the test time requirement is met according to the second total loading speed and the second total loading time; Under the condition that the test time requirement is met, an accelerated fatigue test load spectrum is constructed according to the target load and the second rotation speed.

9. The method for determining the load spectrum of a transmission chain accelerated fatigue test according to claim 5 or 8, characterized in that: Before constructing the accelerated fatigue test load spectrum, the method further includes: The load data for constructing the accelerated fatigue test load spectrum is rounded up to the hundredth place to obtain the first equivalent load; Calculate the equivalent speed according to the first equivalent load; The accelerated fatigue test load spectrum is constructed according to the first equivalent load and equivalent speed.

10. A device for determining load spectrum of transmission chain accelerated fatigue test, characterized in that: The device comprises: A data acquisition unit, used to obtain the design fatigue load of the transmission chain; A load merging unit, used to merge the transmission chain design fatigue load into a preset number of load levels; A calculation unit for determining a conversion load and a conversion speed for each load level according to an equivalent fatigue damage principle; The load spectrum generating unit is used to strengthen the conversion load and conversion speed of each load level to obtain the accelerated fatigue test load spectrum.

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