FISHER LINEAR DISCRIMINANT FUNCTION FOR ADHESIVE BOND STRENGTH PREDICTION.

The prediction of adhesive bond strength based on surface preparation, assuming that there are no delaminations, inclusions, or such cohesive type problems as improper curing, etc. is the goal of this study. Ultrasonically evaluating adhesive bonds that have partially delaminated, is generally easily accomplished by using C-scan techniques, but a major problem arises when the deficiency in the bond is either adhesive or cohesive in nature. Our study involved primarily the adhesive aspect of bond strength, which is related to the surface preparation problem. A completely automated ultrasonic inspection system has been developed for predicting bond strength in metal-to-metal bonded step-lap joints. Results to date, provide a 91% reliability for solving this difficult problem of predicting adhesive bond performance.