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Method for measuring theoretical life of mechanical product

A technology for mechanical products and lifespan, applied in electrical digital data processing, special data processing applications, instruments, etc., can solve problems such as the inability to accurately obtain the optimal confidence interval for the reliability of mechanical products

Inactive Publication Date: 2013-04-24
HENAN UNIV OF SCI & TECH
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Problems solved by technology

[0005] In order to solve the problem that the existing methods cannot accurately obtain the optimal confidence interval of mechanical product reliability, the present invention provides a method for measuring the theoretical life of mechanical products, using multiple criteria to optimize Weibull parameters and reliability confidence intervals to obtain reliable The optimal confidence interval of the property, and then evaluate whether the theoretical life of the product is reliable and reliable under a given confidence level

Method used

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  • Method for measuring theoretical life of mechanical product
  • Method for measuring theoretical life of mechanical product
  • Method for measuring theoretical life of mechanical product

Examples

Experimental program
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Effect test

Embodiment 1

[0185] Embodiment 1 Evaluation of Rolling Bearing Performance Life

[0186] According to the characteristics of the parameters of the friction and wear life of a rolling bearing, the Weibull parameter is set =(30, 2.5, 10), use the inverse function method to simulate the performance failure data of n=9 bearing units (unit: 24h):

[0187] T=(22.1953, 26.4647, 29.8623, 32.9314, 35.9090, 38.9691, 42.3123, 46.2903, 51.8801)

[0188] The simulated 9 failure data are processed by the self-service weighted norm method, and the parameters are calculated The estimated true value of , and then compare the relative error between the true value of the parameter estimate and the true value of the parameter, and compare the reliability estimate of the true value function R 0 (t) and the theoretical value of reliability R 0 and reliability expectation empirical value R 1 consistency between.

[0189] Using norm criterion 1~6, take B=80000, see the result figure 1 with figure 2 . ...

Embodiment 2

[0191] Example 2 Failure Case of Helicopter Components

[0192] The failure data (n=13, unit: h) of a helicopter part 206-011-147-005 is:

[0193] T=(156.5, 213.4, 265.7, 265.7, 337.7, 337.7, 406.3, 573.5, 573.5, 644.6, 744.8, 774.8, 1023.6)

[0194] Adopt norm criteria 1~6, take B=80000, confidence level P=99.999%, use self-service weighted norm method to process failure data, and estimate the true value of parameters and its confidence interval ( , , ) results see Figure 4 , the reliability estimation truth function R 0 (t) and its optimal confidence interval function [R L (t), R U (t)] for results see Figure 5 . For the convenience of comparative analysis, Figure 5 Also shown in the reliability median rank empirical value R 1 .

[0195] Depend on Figure 5 It can be seen that one of the data exceeds the reliability optimal confidence interval function [R L (t), R U (t)], the coverage rate is 12 / 13=92.3%, this percentage is less than the confidence leve...

Embodiment 3

[0196] Example 3 Fatigue life case of a test piece

[0197] The fatigue life data of a group of specimens were measured under the same stress level (n=20, unit: kC):

[0198] T=(350, 380, 400, 430, 450, 470, 480, 500, 520, 540, 550, 570, 600, 610, 6 30, 650, 670, 730, 770, 840)

[0199] Using norm criterion 1 and 4~6, taking B=80000, confidence level P=90%, the results obtained by self-help weighted norm method are shown in Image 6 with Figure 7 . For the convenience of comparative analysis, Figure 7 Also shown in the existing method (probability weighted moment method) reliability estimation true value result R and reliability expectation empirical value R 1 .

[0200] Depend on Figure 7 It can be seen that the reliability estimation truth function R of the bootstrap weighted norm method 0 (t) with existing methods to estimate the truth function R against the reliability expectation empirical value R 1 The consistency is very good. Moreover, the 20 reliability ex...

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Abstract

The invention discloses a method for measuring theoretical life of a mechanical product. The method includes evaluating an optimum confidence interval of reliability in Weibull distribution of three parameters on the basis of life test data of samples by means of self-service norm weighting method, establishing the optimum parameter information vector of the Weibull distribution by six minimum norm weighting standards on the basis of empirical value and theoretical value of reliability, subjecting the optimum parameter information vector to self service and sampling, generating parameter information vector, solving estimated true values of parameters and confidence intervals of the estimated true values under condition of giving the confidence level, setting up an estimated true value function and an optimum confidence interval function of the reliability according to the estimated true values and the confidence intervals, and solving the theoretical life of the mechanical product. A plurality of different norms are optimized and select to process original life data, and the optimum information vector of the Weibull distribution of a plurality of side characteristics can be displayed integrally, and measurement of the theoretical life of the product is optimized after twice optimization.

Description

technical field [0001] The invention relates to a test evaluation method of reliability optimal confidence interval based on multi-criteria optimization, in particular to a method for measuring the theoretical life of a mechanical product. Background technique [0002] With the development of science and technology, many mechanical products, such as bearings, gears and hydraulic pumps, etc., especially for bearings, gears and hydraulic pumps used in modern aerospace systems, have put forward stricter requirements for performance and life reliability. To ensure its safe and reliable operation. [0003] Whether the theoretical life of the product is reliable and trustworthy requires experimental evaluation. So far, in the reliability test evaluation of mechanical products, the three-parameter Weibull distribution has been widely used, and the main focus is on Weibull parameter estimation. The methods used include the maximum likelihood method and the least squares method, and...

Claims

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Application Information

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IPC IPC(8): G06F19/00
Inventor 夏新涛徐永智金银平尚艳涛陈龙
Owner HENAN UNIV OF SCI & TECH
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