Currently, no method exists which can reliably determine the tensile strength of an adhesive-bonded finger joint in lumber using only nondestructive procedures. Typical quality assurance techniques using limited destructive testing and proof loading cannot provide the continuous real-time data on product quality necessary to optimize production control. The Phase I research successfully demonstrated the feasibility of using an acoustoultrasonic (AU) nondestructive evaluation (NDE) technique to predict joint tensile strength for use as the input parameter for a statistical process control (SPC) procedure. The Phase II research will focus on (a) refining the AU technique; (b) improving the SPC limits for a more diverse group of joint defects; and (c) developing a model for AU data which represents production material. Achieving these goals will enable successful commercialization in Phase III.Applications:It is envisioned that a commercially available device for process control of finger jointed lumber will find immediate application in the manufacture of glued-laminated beams. Eventually, finger-jointed lumber of improved reliability should gain more widespread acceptance for other structural applications currently using solid lumber. Extrapolation of the research results to the process control of other manufactured wood composites will also result from the successful completion of Phase II. Hartford Steam Boiler Inspection Technologies, a major manufacturer of acousto-ultrasonic and acoustic emission test equipment, is the Phase III cooperator and will enhance the commercialization potential of this technolo8Y
