ADHESIVE BOND EVALUATION BY NONDESTRUCTIVE TESTING TECHNIQUES

THE USE OF ADHESIVE JOINTS IN THE CONSTRUCTION OF VARIOUS PRODUCTS IS AN ATTRACTIVE ALTERNATIVE TO MECHANICAL FASTENERS. THE GREATEST PROBLEM IS STRUCTURAL BONDING IS THE INABILITY TO QUANTIFY THE STRENGTH OF THE BONDED ASSEMBLY FOR DESIGN, QUALITY CONTROL OR MAINTENANCE. CURRENT NONDESTRUCTIVE EVALUATION METHODS HAVE NOT BEEN SUCCESSFUL IN SOLVING THIS PROBLEM. THIS PROPOSAL IS DIRECTED TOWARD THE EVALUATION OF THE FEASIBILITY OF UTILIZING MULTIPLE-VARIABLE NDE METHODS TO PROVIDE FAST, COST-EFFECTIVE, RELIABLE DETERMINATION OF THE STRENGTH OF ADHESIVE BONDS THROUGH THE USE OF THE IMPACT SONIC WAVE SPECTRAL ANALYSIS METHOD. THE POTENTIAL FOR APPLYING THIS METHOD IS EVIDENCED BY ITS PREVIOUS SUCCESSFUL APPLICATION TO EVALUATION OF WOOD AND WOOD PRODUCTS. VARIATIONS IN MATERIAL TYPE, BONDED AREA, QUALITY, AGING, STRESS HISTORY, DENSITY AND CURING WILL BE EVALUATED BY SONIC WAVE NDE METHODS, COMBINED WITH DESTRUCTIVE TESTING. A MODEL WILL BE DEVELOPED AND VERIFIED WHICH CAN PREDICT BOND STRENGTH WITHIN A TARGET OF + 15 PERCENT.