Bonding Defect Imaging in Glulam with Novel Air-Coupled Ultrasound Testing

The objective of this chapter is to provide an overview of novel non-destructive testing methodologies for bonding quality assessment in glued laminated timber developed within a recently completed Swiss National Science Foundation research project (Sanabria, 2012). The focus is set on air-coupled ultrasound testing, which has previously been applied to wood-based panels typically up to 50 mm thick. A novel prototype capable of transmitting ultrasound signals through up to 500 mm thick glulam was developed. A computerized-scanning system allowed imaging of Sergio J. Sanabria Laboratory for Wood Physics, Institute for Building Materials, ETH Zurich, Switzerland Roman Furrer Swiss Federal Laboratories for Materials Science and Technology, Switzerland Jürg Neuenschwander Swiss Federal Laboratories for Materials Science and Technology, Switzerland Peter Niemz Laboratory for Wood Physics, Institute for Building Materials, ETH Zurich, Switzerland Urs Sennhauser Swiss Federal Laboratories for Materials Science and Technology, Switzerland Bonding Defect Imaging in Glulam with Novel Air-Coupled Ultrasound Testing