Structural integrity of smart laminates

The effects of embedded piezoceramic actuators and sensors on the structural integrity of the host laminated materials have been investigated using finite element analysis and fracture mechanics approach. Double cantilever beam and four point flexural tests were conducted on smart laminates with pre-set cracks to measure the fracture resistances at piezoceramic/laminate and interlaminar interfaces. A two- dimensional finite element code was developed to calculate the stress intensity factors for bi-material interface cracks. It was found that the mode I fracture resistances at piezoceramic/laminate interfaces varied from 3.64 to 4.72 Nmm-3/2, much lower than both the mode I fracture resistances for interlaminar delamination which varies from 29.6 to 76.8 Nmm-3/2 for different ply orientations and the mode I fracture resistances (34.8 approximately 53.8 Nmm-3/2) for cracks inside the piezoceramic actuators. Therefore, the piezoceramic/laminate interface is the weakest interface where debonding may first start when out-of-plane actuation or load is applied.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.