Thermography Research Group Vibrothermography image of a cracked stator vane. Welcome to the web site of the thermography research group at Iowa State University's Center for Nondestructive Evaluation and Department of Aerospace Engineering. Our goal is to advance the state-of-the-art in thermographic nondestructive testing through basic scientific research. Our primary current efforts are focused around vibrothermographic nondestructive testing. Vibrothermography, also known as "thermosonic", "sonic infrared", and "Sonic IR", involves exciting a specimen with vibration and looking for heat generated at cracks. A piezoelectric stack generates the high amplitude vibration and the specimen is imaged with an infrared camera to see vibration-induced heating of cracks and flaws in the material. Current theory suggests that the heat is generated by frictional rubbing between crack faces. Our research group is working simultaneously to better understand the crack heating and vibration, and to develop improved measurement apparatus and experimental procedure. We are actively partnering with government agencies and some of the biggest corporate names in aerospace to assist in the development and deployment of vibrothermography. If you are interested in this technology, please contact Professor Stephen D. Holland for more information.