A novel concept, the fracture efficiency, is proposed in this dissertation as a
performance index of fracture specimen designs for adhesive bonds. Evaluated based on a
simple quantity, the fracture efficiency parameter, the fracture efficiency represents how
much crack driving force a certain specimen design can produce along the bondline for a
given maximum non-singular stress in the adherends. In this dissertation, a study of
membrane peeling specimens shows that various existing test geometries have little
difference in the fracture efficiency. Furthermore, the study shows that it is unlikely to
develop new n1embrane peeling tests with high fracture efficiency. Therefore, gross
inelastic energy dissipation in the film specimen may occur when using the membrane
peeling tests, and may result in large errors in the film adhesion measurement when only
elastic material response is considered in the analysis. As a result, the use of a backing
material for film adhesion measurement is suggested because of the significant increase in
the fracture efficiency when a proper backing material is used. Besides the use as one of
the guidelines for fracture specimen designs, it is also demonstrated in this dissertation that
the fracture efficiency parameter can also be used to help one determine the validity of a
measured bond fracture strength.
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