Analysis of adhesion and interface debonding in laminated safety glass

Abstraet-A tension adhesion test is developed and analyzed to characterize polymer/glass adhesion in laminated safety glass. Laminated safety glass typically consists of two sheets of glass bonded by a polymer adhesive interlayer, usually plasticized poly(vinyl butyral). In the tension test, a rectangular laminate specimen is cracked on both glass sides, and loaded under a remote tension P at a constant displacement rate. The load on the specimen typically rises to a peak or deflection point load, P*, and the value of P* depends on the adhesion between the polymer interlayer and the glass. The peak load P* can be used as a characterization of the adhesion strength of the interface, but does not give a sample geometry-independent value for the adhesion. However, using a micromechanical model of debonding and a detailed finite element computation, the experimental data can be analyzed to determine the fracture toughness, and shear and normal strengths of the interface. The relationship between the peak load and the mechanism of debonding can also be analyzed using the debond finite element model. The estimated fracture toughness for the high, medium, and low adhesion samples are 295 J/m2, 154 J/m2, and 104 J/m2, respectively.