Estimation of adhesive bond strength in laminated safety glass using guided mechanical waves: Part I. An energy velocity approach

Adhesion levels in laminated safety glass samples, ie windshields, have been assessed using both a non-destructive evaluation method based upon an energy velocity guided wave approach and a commonly used destructive testing method. Laminated safety glass consists of a plastic interlayer surrounded by two glass plates. The interfaces between the plastic interlayer and the two adjacent glass plates are assumed to be imperfect and are modelled using a bed of longitudinal and shear springs. The spring constants are estimated using fracture mechanics in conjunction with surface analysis of the plastic interlayer and of the two adjacent glass plates via atomic force microscopy and profilometer measurements. Energy velocities calculated using this theoretical multilayered model are compared with energy velocity values obtained experimentally using laminated safety glass samples with different adhesion levels. Results show that an energy velocity approach can successfully be used to non-destructively estimate adhesive bond strength in laminated safety glass.