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

The development of an expert system for ultrasonic testing (UT) can co ntribute to the improvement and standardization of inspection levels i f the technique and experience of the UT engineer can be incorporated into a knowledge data base. It is considered that such an expert syste m will be one way to solve the problem of the predicted shortage of UT engineers in the near future. The present system was originally devel oped as a system having a knowledge-based system and an inference engi ne which are combined with a blackboard model and frame model. In the developed expert system, which is combined with a man-machine interfac e, it may be advantageous to use a production rule and forward inferen ce. 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, t he results obtained by the present system agreed with those obtained b y the UT engineer up to about 90% of the time. It was therefore confir med that the expert system is applicable as a method of inference for weld flaws using ultrasonic testing data.