Lifetime of High-Parameter Structures under Repeated and Prolonged Thermomechanical Influences

Abstract

The article considers the main provisions and equations of the applied theory of inelasticity, which belongs to the class of flow theories under combined hardening. The material functions that close the applied theory of inelasticity are distinguished, and a basic experiment is formulated. The prediction of the material lifetime of structures under non-isothermal cyclic loads is carried out on the basis of the analysis of the durability of the combustion chamber edge of the diesel piston and the uncooled conical nozzle tip during heat changes. Calculated lifetime estimates based on the applied theory of inelasticity are compared with the results of experiments and traditional methods of lifetime estimation. Examples of estimating the lifetime of a structural element of a long-term lifetime power unit are also considered. The loading modes leading to a significant reduction in the lifetime are shown.

Keywords

• inelasticity
• lifetime
• durability
• non-isothermal cyclic loads
• damage accumulation