Volume 25, Issue 4 (July 1997)
New Technique for Evaluating Damping of Longitudinal Free Vibration in Wood-Based Materials
Classical log-decrement techniques have been used to evaluate the damping property of materials. However, the consistency and repeatability of the methods when applied to wood and wood-based materials have been found lacking. A different way to view the free vibration of a single-degree-of-freedom system in the x − ˚x plane is presented. A new method that uses all sample points and does not require a knowledge of the initial conditions to determine the damping properties is developed. A comparison between the new method and the classical method is made for three wood-based materials: solid wood, medium density fiberboard (MDF), and particleboard. The results show that the new method is more consistent and repeatable in measuring damping than the classical method. For the six cases examined, there was an absolute average difference of 3.8% in measuring log-decrement between the methods.