—The influence of a basalt fiber and the type of its packing on the strength properties of a composite material based on fresh ice is studied. The laws of damage accumulation in the ice composite material are analyzed by acoustic emission. Bulky samples fabricated by layer-by-layer freezing under natural conditions are used in experiments. An increase in the bending strength by 1.5 times and an enhancement in the life of the ice composite are observed after a twofold increase in the filler content. The strength scale effect is discussed.
The paper explores the problems of maintaining the reliability of steel structures used in hazardous industrial facilities. It aims to introduce a new parameter for the rapid assessment of structural changes in the material of critical structures. It developed a method for rapid assessment of structural changes in the material of critical structures using a non-destructive method based on parameters that are sensitive to degradative changes in structure. It establishes a correlation between speed of sound and toughness for given states of the pipe metal, based on which the method was developed. It substantiates the applicability of these parameters to assess the degree of degradation. A method is proposed for estimating the residual service life of metal in a trunk gas pipeline by changing the speed of sound.
The change in the impact toughness of the gas main steel after operation for 50 years is studied. The mechanical properties of the pipe steel before and after operation are compared.
An estimate is made of the ultimate condition of main gas pipelines after long-term operation in the North by determining the impact strength of samples from the pipe material (in various conditions), and correlation of the values obtained with the speed of sound in materials.
The problems of ensuring the reliability and safe operation of long-running hazardous industrial facilities, in particular gas pipelines, after 50 years of operation are considered. The goal of the work is developing a method for assessing metal embrittlement of long-running main gas pipelines (MG) using a non-destructive method for monitoring and improving operational reliability. Experimental studies of the samples of the pipes of the main gas pipelines revealed the parameters most sensitive to the processes of structural degradation. The applicability of those parameters to assessing the degree of degradation is substantiated. Analysis of the results of mechanical and acoustic studies revealed correlation with an essentially large value of the correlation coefficient. Based on this correlation, a method for assessing the toughness has been developed. The experimentally obtained limit values of the studied characteristics at which the operation of the structure becomes dangerous are presented. A flowchart has been developed for monitoring changes in the toughness of the gas pipeline steel after long-term operation. The experimental results and developed method for estimating the limiting state of the gas pipeline material were used during technical diagnostics of non-project sections of the Mastach — Berge — Yakutsk gas pipeline to determine real operational characteristics and form a database of the studied indicators for their further monitoring. The proposed method will improve the efficiency of accumulated information on the structural reliability and provide the possibility of assessing the degree of pipe metal degradation without conducting mechanical tests and making samples in the process of technical diagnostics thus reducing the material costs for conducting scheduled maintenance of the pipelines.
A technique is proposed to estimate the limiting state of gas main pipes having operated for a long time, and it is based on a correlation between the velocity of sound and mechanical parameters. The limiting values of the characteristics at which the operation of a construction become dangerous are obtained.
The internal pressure test method and test results are presented for pressure vessels at a low-temperature and applied external electric potential conditions. The rupture mechanisms, plasticity and crack resistance characteristics, and times until rupture (rupture lifetimes) are compared between the tested pressure vessels and vessels exposed to a constant external electric potential. The positive effect of the external electric potential on the process of rupture of pressure vessels is noted.
