Effect of Mechanical Properties of Adherend on Adhesive Bond Strengths

摘要

The report demonstrates that the strength of an adhesive-bonded lap joint increases linearly with the length of the lap up to a load determined by the mechanical properties of the adherend. This is true for any adherend provided that it is homogeneous and that the failure is cohesive. Plots of lap length/adherend thickness versus load, referred to as L/t curves, showed an unexpected and unexplained plateau in the curve prior to the familiar asymptotic leveling normally seen. These plateaus have either been ignored or unrecognized in the past. Preliminary examination of the plateaus shows that they occur at the (Sy) value, defined as approximately 55% of the load at which the tensile yield of the adherend is reached. Their location on the curve depends upon the thickness and type of adherend used. Several sets of graphs are presented in support of the concept that the mechanical properties of the adherend limit the performance of adhesives in adhesive-bonded joints. (Author)