Predicting Residual Energy Release Rates due to Bonding Geometrically Dissimilar Adherend Surfaces

摘要

A numerical approach using a finite element (FE) commercial software is presented to estimate the residual energy release rate that arises from bonding geometrically dissimilar adherend surfaces. Pressure is applied at room temperature during the cure process to bond the two adherends. A residual energy release rate may arise from the presence of a defect after the adhesive cures and pressure is removed. After the cure pressure is removed, the crack driving force may be sufficiently high for crack propagation or it could reduce the fracture capability for flight conditions. The virtual crack closure technique within the FE software code is used to estimate the total energy release rate, and confirmed by using an alternate numerical fracture mechanics approach. The asymmetric double cantilever beam test configuration is then used to characterize the Mode I fracture toughness (Gc) at this bi-material interface to enable calculation of fracture structural margins.