DIGITAL IMAGE ANALYSIS SYSTEM FOR MONITORING CRACK-GROWTH AT ELEVATED TEMPERATURE

THE OBJECTIVE OF THE PROPOSED RESEARCH IS TO DEVELOP A NEW APPROACH TO THE PROBLEM OF LOCATING THE TIP OF A CRACK AND MEASURING ITS GROWTH. THE PROPOSED SYSTEM SHOULD BE CAPABLE OF PERFORMING THIS TASK AUTOMATICALLY, AT ROOM OR AT ELEVATED TEMPERATURE, WHILE THE SPECIMEN IS SUBJECTED TO FATIGUE CYCLING IN AN OVEN. THE PROPOSED SYSTEM WILL CONSIST OF A PROBE, IMAGING THE CRACK TIP ON A FIBEROPTIC IMAGE GUIDE, CARRYING AN ENLARGED IMAGE OF THE CRACK TIP TO A DIGITAL IMAGE ANALYSIS SYSTEM. A MICROCOMPUTER PROGRAM WILL BE PREPARED TO LOCATE THE CRACK-TIP POSITION AND DIRECT THE SERVOPOSITIONER TO RELOCATE THE HEAD OF THE PROBE THAT IS OBSERVING THE CRACK TIP. THE MAXIMUM OPERATING TEMPERATURE WILL BE LIMITED ONLY BY THE CAPABILITY AND LIMITATION OF THE OPTICAL SYSTEM AND THE FIBER-OPTIC IMAGE GUIDE SELECTED.