INFLUENCE OF THE LIMIT VALUE OF THE DAMAGE PARAMETER ON THE ESTIMATION OF THE LONG-TERM STRENGTH OF RING LAMINAS
In this work, a research methods of complex problem solution to estimate strength and durability of flat laminas and multiple layer shells of rotation with an account of plastic deformations, temperature creep, the hydrogen corrosion and degradation of material’s properties in time, is presented. The practical solutions to the problems of calculating the stress-strain state of a flat lamina with a hole was obtained. The lamina was under pressure at a temperature of 500 °C. The dependence of the time of the onset of the limiting state on the value of the damage parameter for three different pressure values is investigated. The components of the stress-strain state and the time to failure of the laminas was determined. As the limiting state, moments of the beginning of the destruction process and the complete destruction of the laminas were considered. In the course of the research, it was found that the choice of the limiting value of the damage parameter has a significant effect on the evaluation of the time of fracture, the laminas, and this effect is especially strongly manifested when calculations are performed taking into account the motion of the destruction front. In case of incorrect selection of the damage parameter, the estimate of the time before the destruction can be both overestimated and understated. On the basis of the obtained results of calculations, recommendations are formulated for the choice of the values of the damage parameter.