Recent Results in Active and Passive SHM

This paper reviews recent active and passive results obtained at the Laboratory for Active Materials and Smart Structures (LAMSS) of the University of South Carolina, USA. The active SHM research has focused on detecting various types of composite damage using guided-wave interrogation and sensing. The composite damage considered covered seeded delaminations associated with barely visible impact damage (BVID). The seeded delaminations were created through the insertion of thin Teflon-film patches during composite fabrication. Multiple delaminations at the same x-y location were also studied. [+45/90/−45/0]nS quasi-isotropic layup plates were considered. The Teflon insert specimens were modeled and tested using guided waves transmitted and received with piezoelectric wafer active sensors (PWAS). Scanning laser Doppler vibrometer (SLDV) measurements were also performed.