Vst residual life estimation algorithm based on low-cycle loading criterion in real time

Due to the significant wear and tear of oil and petroleum product tanks in Russia, there is a need for continuous monitoring of their technical condition. The article provides an overview and analysis of methods for assessing the stress-strain state of the tank wall. The advantages and disadvantages of these methods were identified, as well as the possibility of assessing the stress-strain state of the tank in real time was justified. Calculations of ring stresses were made according to the moment-free theory of shells, calculation of equivalent Von-Mises stresses in ANSYS medium. An analysis of calculations was carried out, the conclusions of which are consistent with the literature data. As a result of the application of various shell theories, production faces a dilemma - or the ability to get operational, but less accurate results and predictions, or use strain gauges to determine wall stresses, or use additional tools in the form of 3D scanning of the tank surface with subsequent processing of data and transfer of the obtained model to the FEA-environment to detect equivalent stresses by Von-Mises, while any efficiency of the process is lost. Strain gauges are one of the effective means of assessing the stress-strain state of the tank wall, but their calibration is not an easy task. The existing diagnostic tools do not allow to estimate the residual wall life by low-cycle loading in real time. An algorithm is proposed for estimating the residual life of the RVS according to the criterion of low-cycle loading in real time, which allows detecting potential problems in advance, maintaining the tank in a timely manner, while reducing the risk of an accident and subsequent more expensive repairs, and promptly taking measures in case of an emergency. The developed algorithm can be used for continuous tank diagnostics.