RU2002131037A - METHOD FOR DETERMINING DAMAGE OF LOADED MATERIAL AND ITS OPERATING RESOURCE - Google Patents

Claims (2)

1. A method for determining the damageability of a loaded material and a service life resource, including determining damage parameters by tensile testing of material samples and under cyclic loading to failure mode, measuring the physical parameters of material samples by non-destructive testing methods during testing, characterized in that some of the material samples are subjected to thermal deformation aging varying degrees n, and all samples are tested simultaneously with static and cyclically x loads with a level and direction corresponding to the maximum acting in the structure, with a time step from the total test time, after each time step, the material of the samples is subjected to relaxation tests, the current limit of macroelasticity, the limit of macroelasticity of the sample not subjected to thermal deformation aging (n = 0) are determined, the limit of macroelasticity at the time step preceding the destruction of the sample and calculate the current measure of damage by the formula

where P is the current measure of damage,%; σ ₀ is the current limit of macroelasticity, MPa; σ $\genfrac{}{}{0ex}{}{\text{floor}}{\text{0}}$ - the limit of macroelasticity of the sample not subjected to thermal deformation aging, MPa; σ $\genfrac{}{}{0ex}{}{\text{cr}}{\text{0}}$ - the limit of macroelasticity at the time step preceding the destruction of the sample, MPa, then, the curves of the dependence of the current measure of damage on the test time are built for each degree of thermal deformation aging n of the material of the samples P = f _n (τ), the degree of aging of the material of the structure, for example, by electron microscopy, and the current measure of damage to the material of the structure according to the results of the relaxation test method on samples cut from the design zones with maximum stresses and the test time for the current damage measures to it, after which the design life is determined from the following dependence:

where τ _to - test time for the current measure of damage; τ _p - test time to the step preceding the destruction of the sample, h; T _to - the time of operation of the structure until the time of control, years; T _p - design resource, years, and the residual life of the structure T _OST according to the formula T _ost = T _p -T _to . 2. The method according to claim 1, characterized in that the measurement of the physical parameters of the samples by non-destructive testing methods, including methods sensitive to the level of stress state of the samples, during the test after each time step is performed without removing the static load.