Estimation of the reliability of 09G2S steel structures operating in Arctic conditions

Abstract

The data on damage accumulation and service life of the elements of welded metal structures made of 09G2S steel during their operation in the Far North (regions located mainly north of the Arctic Circle) are presented. The mechanism of damage accumulation in steel undergoing a low-temperature ductile-brittle transition was evaluated by measuring the impact toughness of the V-notched specimens (KCV) in the corresponding temperature range. Analysis of experimental data revealed that the most severe loss in the weld plasticity occurs in the heat-affected zone characteristic with stress localization and accelerated accumulation of the defects and crack development resulting in a decrease the lifetime of steel structures at low temperatures. The method for estimating integral damage of steel welded structure subject to a ductile-brittle transition is proposed proceeding from the Kachanov-Rabotnov damage accumulation theory with due regard to the operating time of the material in severe climatic conditions. Comparison of numerical estimates of accumulated damages in the material of the structures operating in extreme conditions of the Republic of Sakha (Yakutia) and in the climate of the Krasnoyarsk Territory of the Russian Federation allows us to conclude that MTBF and lifetime of the structures are largely determined by climatic conditions.