DEVELOPMENT OF EXPERT-SYSTEM FOR ESTIMATION OF WELD FLAWS BY ULTRASONIC TESTING

The development of an expert system for ultrasonic testing (UT) can contribute to the improvement and standardization of inspection levels if the technique and experience of the UT engineer can be incorporated into a knowledge data base. It is considered that such an expert system will be one way to solve the problem of the predicted shortage of UT engineers in the near future. The present system was originally developed as a system having a knowledge-based system and an inference engine which are combined with a blackboard model and frame model. In the developed expert system, which is combined with a man-machine interface, it may be advantageous to use a production rule and forward inference. The inference was performed in two steps. The causes of weld flaws were firstly inferred from the welding condition, and then the final result was determined from the UT data. When the present expert system was applied to diagnosis of the welding flaw of a welded structure, the results obtained by the present system agreed with those obtained by the UT engineer up to about 90% of the time. It was therefore confirmed that the expert system is applicable as a method of inference for weld flaws using ultrasonic testing data.