Date: Thursday, May 21st
Presenter: Dr. John Parmigiani, OSU Mechanical Engineering
In order to design composites and laminated materials, it is necessary to understand the issues that govern crack growth at interfaces. LEFM has proven to be a useful tool for this purpose and its basic applicability and limitations will be reviewed. Presented as a means of extending from the realm of LEFM, cohesive zone models are will be discussed. In particular, a specific CZ approach will be described. Two applications of this method will be discussed. First, the interface fracture of an asymmetric double cantilever beam, a nominally mixed mode fracture, will be shown to be pure mode one for the case of very low shear strength bonding. Second, the issue of crack penetration vs. deflection will be considered. Specifically, the criteria presented will constitute a correction to a well-known published result.