Development of a portable ultrasonic timber properties monitoring device

For maintenance and rehabilitation of timber structures, reliable methods for in-situ assessment of the strength and degradation rate in terms of strength loss over a period are essential. Nondestructive evaluation using ultrasonic techniques has been found to be more accurate in assessing the condition of timber than the conventional practice of visual inspection. However, to increase the speed of field data collection and interpretation, it is important to develop a portable ultrasonic timber properties monitoring device incorporating equations to predict stiffness and strength properties of timber from ultrasonic measurements. This research presents the development of such a device that can be conveniently used by a field engineer or technician with very little knowledge of ultrasonics. The hand-held ultrasonic instrument incorporates: (1) a high voltage pulser; (2) dry coupled ultrasonic sensors; (3) clamp attachments to standardize the pressure on the sensor heads; (4) frequency domain analysis algorithms; and (5) display of engineering material properties (stiffness and strength). The user inputs information such as travel distance, density and Poisson´s ratio. The device analyzes the signals and predicts parameters such as modulus of elasticity, modulus of rupture, and extent of degradation of timber