RU2010116329A

RU2010116329A - METHOD FOR FORECASTING RESIDUAL RESOURCE OF METAL PRODUCTS AND DEVICE FOR ITS IMPLEMENTATION

Info

Publication number: RU2010116329A
Application number: RU2010116329/28A
Authority: RU
Inventors: Алексей Леонидович Бобров (RU); Алексей Леонидович Бобров; Людмила Николаевна Степанова (RU); Людмила Николаевна Степанова; Сергей Иванович Кабанов (RU); Сергей Иванович Кабанов; Евгений Юрьевич Лебедев (RU); Евгений Юрьевич Лебедев
Priority date: 2010-04-23
Filing date: 2010-04-23
Publication date: 2011-10-27
Also published as: RU2448343C2

Abstract

1. Акустико-эмиссионный способ прогнозирования остаточного ресурса металлических изделий, заключающийся в том, что изделие разбивают на n секторов, содержащих не менее трех акустических преобразователей, изделие нагружают, регистрируют сигналы акустической эмиссии, измеряют их параметры, осуществляют регистрацию времени прихода сигналов на акустические преобразователи и вычисление по ним координат развивающихся дефектов, отличающийся тем, что предварительно изделие нагружают до 0,5 значения рабочей нагрузки, при этом определяют максимальную активность сигналов, превышающих пороговый уровень Uпор>Uш, (где Uш - уровень шума) и задают скорость подачи нагрузки в зависимости от этой активности, после этого проводят нагружение, превышающее на 10-15% рабочую нагрузку, затем проводят нагружение до максимальной рабочей нагрузки с заданной скоростью подачи нагрузки, регистрируют сигналы акустической эмиссии этих этапов нагружения, проводят кластеризацию сигналов акустической эмиссии по коэффициенту взаимной корреляции сигналов, а остаточный ресурс металлических изделий определяют по формуле ! , ! где N - допустимое число циклов эксплуатации изделия; ! Кин - коэффициент, учитывающий величину относительных напряжений в зоне локализации источника сигналов акустической эмиссии; ! F(EΣ) - функциональная зависимость, отражающая влияние на долговечность изделия суммарной энергии сигналов акустической эмиссии в зоне локализации; !Р - доверительная вероятность безотказной работы изделия; ! α - корреляционный коэффициент определяемый как , где kcp - средний коэффициент корреляции между всеми сигналами источника; ! ki,i+1 - коэ 1. The acoustic emission method for predicting the residual life of metal products, which consists in the fact that the product is divided into n sectors containing at least three acoustic transducers, the product is loaded, acoustic emission signals are recorded, their parameters are measured, and the time of arrival of signals to the acoustic transducers is recorded and calculating the coordinates of developing defects from them, characterized in that the product is pre-loaded to 0.5 of the value of the workload, while maxi is determined the maximum activity of signals exceeding the threshold level Uпор> Ush (where Ush is the noise level) and set the speed of the load depending on this activity, then load is carried out, exceeding the work load by 10-15%, then load to the maximum working load at a given feed rate, the acoustic emission signals of these loading stages are recorded, the acoustic emission signals are clustered by the cross-correlation coefficient of the signals, and the residual life of metal products is determined They use the formula! ! where N is the allowable number of product operation cycles; ! Kin - coefficient taking into account the magnitude of the relative stresses in the localization zone of the source of acoustic emission signals; ! F (EΣ) is a functional dependence reflecting the effect on the product life of the total energy of acoustic emission signals in the localization zone; ! P - confidence probability of product uptime; ! α is the correlation coefficient defined as, where kcp is the average correlation coefficient between all source signals; ! ki, i + 1 - coe

Claims

1. The acoustic emission method for predicting the residual life of metal products, namely, that the product is divided into n sectors containing at least three acoustic transducers, the product is loaded, acoustic emission signals are recorded, their parameters are measured, and the time of arrival of signals to the acoustic transducers is recorded and calculating the coordinates of developing defects from them, characterized in that the product is pre-loaded to 0.5 of the value of the workload, while maxi is determined the maximum activity of signals exceeding the threshold level U _then > U _w (where U _w is the noise level) and set the feed rate depending on this activity, then load is carried out, exceeding the working load by 10-15%, then load to the maximum working load with a given feed rate, the acoustic emission signals of these loading stages are recorded, the acoustic emission signals are clustered by the cross-correlation coefficient of the signals, and the residual life of metal products is determined fissioning of formula

,

where N is the allowable number of product operation cycles;

To _in - coefficient taking into account the magnitude of the relative stresses in the localization zone of the source of acoustic emission signals;

F (E _Σ ) is a functional dependence reflecting the effect on the product life of the total energy of acoustic emission signals in the localization zone;

P is the confidence probability of product uptime;

α is the correlation coefficient defined as

where k _cp is the average correlation coefficient between all source signals;

k _{i, i + 1} - correlation coefficient between two neighboring signals from the source, which are neighboring in time of arrival;

m is the total number of signals from the source;

λ is the defect activity coefficient, determined by the formula

where K ₁ is the coefficient determined experimentally by the time of operation before failure;

And _Δt is the activity of the source of acoustic emission signals in the time interval Δt;

t _to - time of the end of the test;

A _max - maximum activity of the source during the test;

F (A _max ) - load at maximum source activity;

F _max - maximum load during the test.

2. A multi-channel acoustic emission device for diagnosing the residual life of metal products, consisting of 1 ... k channels, each of which consists of a series-connected acoustic transducer, pre-amplifier, filter, main amplifier, the output of which is connected to a non-inverting input of an analog comparator and an analog input -digital converter, and also contains a digital-to-analog converter, random access memory, channel control device, the output of which connected to the computer bus connected to the central processor of the computer, characterized in that narrow channel bandpass filters, analog integrators, analog-to-digital converters of frequency ranges, random access memory of the range code, random access memory of the correlation matrix, microprocessor, are additionally introduced into each channel - a counter of time intervals, while in each channel the output of the main amplifier is connected to 1 ... n inputs of narrow-band filters, the outputs of which are connected s with the first inputs of 1 ... n analog integrators, the second inputs of which are combined and connected to the first output of the timer-counter of time intervals, and the outputs 1 ... n of analog integrators are connected with the first inputs 1 ... n of analog-to-digital converters of frequency range signals, the second inputs of which combined and connected to the second output of the timer-counter time intervals and the first analog input of the microprocessor, the digital outputs of the analog-to-digital converters of the frequency range signals are combined and connected to the input the range code random access memory, and its output via a bi-directional bus connected to the second input of the microprocessor, the analog output of which is connected to the second input of the range code RAM, the output of the correlation matrix random access memory is connected to the third input of the microprocessor, the second analog output of which is connected to the input of the timer-counter of time intervals, and the output of the analog-to-digital converter of the acoustic channel by bus with is dined with the first input of the acoustic signal memory, the second input of which is connected by a bi-directional bus to the second input of the channel control device, and its third input by the bi-directional bus is connected to the fourth input of the microprocessor, the first output of the channel control device is connected to the third input of the acoustic signal memory, its second output is connected to the input of the digital-to-analog converter, the output of which is connected to the non-inverting input of the analog computer an arator whose output is connected to the fourth input of the channel control device.