Estimating of Durability Indexes of Structural Elements Based on Identification of their Deterministic Properties

Abstract

Durability indexes are presented as a consequence of some deterministic properties inherent in the system and (or) their elements, and it is proposed to determine the durability indexes on the basis of analysis of these properties. The most important for estimating the durability are properties related to the lifetime, and the deterministic properties basic for determining the indexes of durability, can be represented by the function of the dependence of the lifetime on the parameter defining the operational conditions. Estimating the durability indexes is reduced to identification of the deterministic properties representing the dependence of the lifetime on the parameter defining the operational conditions. An example of estimating the durability of pipes of superheaters of steam boilers demonstrates the proposed approaches with relatively less complexities. This particular example shows that deterministic properties can have a significant influencing on the durability due to significant differences between the density function of the parameter defining the operational conditions and the density function of the lifetime. The proposed approaches can be recommended for use to estimate the durability indexes of unique technical systems, such as high-power steam boilers and nuclear power reactors, which are usually manufactured in single batches, as well as to estimate the durability indexes of any systems at the stage of their development in order to compare the durability of different constructions.

Keywords

• deterministic properties
• identification
• durability
• computed estimation
• mean time to failure
• bx lifetime