SU1620930A1

SU1620930A1 - Method of determining ultimate long-term strength of articles from brittle material

Info

Publication number: SU1620930A1
Application number: SU894629571A
Authority: SU
Inventors: Сергей Григорьевич Никольский
Original assignee: Ленинградский Политехнический Институт Им.М.И.Калинина
Priority date: 1989-01-02
Filing date: 1989-01-02
Publication date: 1991-01-15

Abstract

Изобретение относитьс к неразрушающим методам определени прочности материалов акустоэмиссионным способом. 2 Цель изобретени - повышение точности за счет исключени вли ни на результат измерени сигналов акустической эмиссии от микротрецин. Изделие дважды нагружают. При первом нагружен ни олрегеч ют величины нагрузки Р{ и Р,, при которых соответственно возникают стабильна акустическа эмисси ч переход их непрерывной эмиссии в дискретную. Выдерживают нагрузку Р до исчезновени сигналов эмиссии ти до возникновени непрерывной эмиссии. При повторном нагружен ии регистрируют интенсивности N и NЈ, соответствуюгще величинам Р( и Р нагрузки, по которым определ ют предел длительной прочности изделий. 1 ил. с «The invention relates to non-destructive methods for determining the strength of materials by an acoustic emission method. 2 The purpose of the invention is to improve the accuracy by eliminating the effect on the measurement result of acoustic emission signals from microtrecin. The product is loaded twice. During the first load, the load values P {and P, at which, respectively, a stable acoustic emission occurs, the transition of their continuous emission to discrete, appear. They withstand the load P until the emission signals eti have disappeared before the occurrence of continuous emission. With repeated loading, the intensities N and NЈ are recorded, corresponding to the values of P (and P loads, which determine the limit of the long-term strength of products. 1 cf.

Description

Изобретение относитс к неразрушающим способам определени прочностных свойств материалов и изделий.The invention relates to non-destructive methods for determining the strength properties of materials and products.

Цель изобретени - повышение точности за счет исключени вли ни на результат измерени сигналов акустической эмиссии (АЭ) от микротрецин.The purpose of the invention is to improve the accuracy by eliminating the influence on the measurement result of acoustic emission signals (AE) from microtrecin.

На чертеже представлены временные характеристики нагрузки интенсивности сигналов АЭ.The drawing shows the temporal characteristics of the load intensity of the AE signals.

Способ осуществл ют следуюгрш образом .The method is carried out in the following manner.

Изделие,дважды нагружают. При первом нагруженин устанавливают стабилизацию интенсивности A3 и измер ют при этой величину Р., нагрузки. Затем разгружают изделие до величины Р2 , при которой АЭ переходит из непрерывной в дискретную, выдерживают эту нагрузку до возникновени непрерывности АЭ или до ее исчезновени и продолжают разгрузку. При повторним нагружении измер ют интенсивности N , и П2 при достижении соответствующих величин Р и Р2 нагрузки. Нагрузку, при которой определ ют предел длительной . прочности, рассчитывают по йормулеThe product is loaded twice. At the first load, stabilization of the intensity A3 is established and measured at this value P., load. Then, the product is unloaded to the value P2, at which the AE goes from continuous to discrete, withstands this load until the appearance of continuity of AE or until it disappears, and the unloading continues. With repeated loading, the intensities N, and P2 are measured when the corresponding values of P and P2 are reached. The load at which the limit is determined is long lasting. strength, calculated by yormula

РгДпЫ, - IMnN RgDpY, - IMnN

Устранение АЭ микрорастрескиванип достигаетс первь м циклом нагрукенилElimination of AE micro cracking is achieved by first loading a cycle

О)ABOUT)

оз оoz o

Claims

with exposure under constant load P0. AE microcracking decays the faster, the higher the constant load. But if to withstand the product under load R., then it can be destroyed during the exposure. To prevent this from happening, it is necessary to reduce the load so as to prevent the destruction of the product, but not to weaken the attenuation of the micro-cracking AE. Reducing the load before a continuous AE goes to discrete, keeping the product under an appropriate load until the AE disappears or goes back to a continuous one allows for subsequent loading to exclude AE micro-cracking, which ensures accurate determination of NJ and N4 intensities products. Invention Formula

The method of determining the long-term strength of products made of brittle material, which consists in loading and unloading the product and recording the load, and the intensity of acoustic emission, judged by the strength limit, characterized in that, in order to improve the accuracy, the load carry out an increasing load up to the value P ,, at which the intensity of acoustic emission stabilizes, unloading is carried out up to the value P, at which, the continuous intensity of acoustic emission goes into discrete, maintain the product under load P until the acoustic emission disappears or until the acoustic emission continuity occurs, continue unloading the product, then reload, and record the intensities N ,, and N of acoustic emission at repeated loading at the corresponding values of P. and radar load.