Effect of Voids on the Crack Kinking in Single Lap Joints
MetadataShow full item record
Polymer matrix composites are used extensively for their exceptional mechanical properties. The effect of voids on the energy release rate of interface crack has been studied before; however none of the studies investigated the effect of voids on the kinking of a crack from the interface into the adhesive film. In the following report, a parametric study is conducted to understand the effect of the void size, the void shape and the void location on the kinking of an interface crack in single lap joint. An interface crack can originate from the maximum shear stress or the maximum normal stress that occurs at the interface between the adherend and the adhesive. A void is placed ahead of the crack tip at various distances in the Finite elements model to determine the critical distance. After determining the critical distance, the effect of the void radius and the void shape are examined on the crack kinking process. The interface crack is assumed to propagate a distance of 0.1mm at different angles ranging from 0 to 90 degrees with an increment of 10 degrees. The energy release rate is calculated by the revised virtual crack closure technique (RVCCT). The total energy release rate is calculated by adding Mode I and Mode II from the revised virtual crack closure technique (RVCCT) and justified by the J- integral method. Since the crack is an interface crack, the crack is expected to have a mixed mode behavior. A force boundary condition is applied. As the force increases, Mode I and Mode II increase. Moreover, it is evident from the results obtained that a void could lead an interface crack to kink into the adhesive, if the distance between the void and crack tip is significantly small to cause an interaction between the crack tip and the void.
Sengab, Ahmed M (2015). Effect of Voids on the Crack Kinking in Single Lap Joints. Master's thesis, Texas A & M University. Available electronically from