ANALYSIS AND CHOICE OF DESCRIPTION METHODS FOR PROCESSES OF FATIGUE, CREEP AND LONG TERM STRENGTH FORECASTING FOR HIGH-SPEED FORCED DIESELS PISTONS

Abstract

The work is devoted to the analysis and choice of description methods for processes of fatigue, creep and long-term strength forecasting of high-speed forced diesel pistons at the initial design stages. The existing description methods for the process of the combustion chamber parts fatigue of high-speed diesel engine are analyzed from the point of view of their use efficiency, especially at the initial design stages. The description methods are also considered for creep process in the material of high-speed engine combustion chamber parts. A method is proposed for estimating of accumulated damage in a piston material under conditions of low-frequency cyclic creep action. The forecasting method is presented for the long-term strength of the piston combustion chamber edge based on the operating model of a high-speed diesel engine, which takes into account the combined effect of low-frequency fatigue and creep on the damage accumulation process. It is proved that it is advisable to use the deformation criteria of fatigue strength to predict durability in the field of low-cycle fatigue.