Reliable low-cost NDE of composite marine sandwich structures

The research summarized in this paper centered on the development of reliable low-cost NDE methods for marine composites, especially composite sandwich structures. It has involved the investigation of vibration-based mechanical identification of thick composite structures, low velocity impact and damage studies of foam-cored composite sandwich structures, as well as the development- and application-oriented investigation of various other NDE methods. Composite materials are being increasingly deployed into ship structures, and generally into both the civilian and military sectors of the US economy. It thus becomes essential to have rapid, low-cost and reliable methods for obtaining mechanical property data for these materials, and assessing damage in them. The research has sought to apply low-frequency vibration, ultrasonic, acoustic absorption, thermosonic and especially, acoustic emission methods to the characterization and integrity assessment as well as strain rate and nano-phasing behaviors of composite marine structures.