engleski

Outline of an expert system for an on-line stress estimation

Concept of an expert system for an on-line estimation of strength margin in thick walled component during the plant operation is presented. The heart of the concept lies in the creation of a knowledge base by simulating transient temperature field and the corresponding stress field. The knowledge base is created by the simulation of numerous different operational conditions of the component. Each simulated case within the base is described with a set of linguistic variables. In service, during the plant operation, the system evaluates steam temperature, pressure and mass flow input signals (representing current case description), and searches the knowledge base. The search is terminated when the most similar cases to the current one are found. Finally, in order to produce the current strength margin estimation, the system interpolates among the strength margins of previously selected cases. Six expert systems were made and the one with the knowledge base consisting of 2.172 stored operational situations, achieved mean estimation error less than 10% of allowable stress in the material at the temperature of 560°C.

Thermal power plant; thermal stress evaluation; expert systems

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