Fracture toughness of steel adherend bonded with two-part polyurethane
adhesives: Double cantilever beam tests under static loading
Abstract
The ductile structural adhesives such as a polyurethane adhesive are
developed in recent years. This study is intended to measure the
fracture toughness under Mode I loading of two-part polyurethane
adhesives using double cantilever beam (DCB) tests. Two types of
polyurethane adhesives and the effect of adhesive thickness on the
fracture toughness are discussed. Plastic deformation of the steel
adherends occurred in both adhesives for both adhesive types and
thicknesses. Therefore, the arrest load out of consideration of a
plastic deformation was evaluated the fracture toughness of the DCB
specimens. As a result, the fracture toughness of the polyurethane
adhesive is higher for higher tensile modulus and adhesive strength. In
addition, the fracture toughness is higher for a larger adhesive
thickness. The analytical results based on the triangle cohesive zone
model using zero-thickness cohesive elements are agreed with the
experimental results.