EXPERIMENTAL STUDY ON MEASUREMENT METHOD OF NATURAL FREQUENCY OF WOODEN CYLINDER COLUMN BY LONGITUDINAL VIBRATION

Abstract

 The natural frequency of wood by the longitudinal vibration method is effective as an index to evaluate the Young's modulus of wood and can be applied to quality control of structural materials, so it has been adopted as a method to estimate or evaluate mechanical properties in factory production lines and construction site. To measure the natural frequency, measurement sensors such as microphones and accelerometers are used, but the measurement at the construction site depends largely on the characteristics of the measurement sensors, and differences in the sensors affect the accuracy and workability of the measurement. Furthermore, when accelerometers are used, there are several ways to fix them, and it is difficult to determine which method is appropriate.

 The purpose of this study was to clarify how to accurately and efficiently measure the natural frequency of wood at a construction site using the longitudinal vibration method. Microphones, laser displacement meters, and accelerometers were used as different measurement sensors, and contact methods via adhesive tape, rubber bands, and screws were used as different methods of fixing the accelerometers, and the effects of these methods on the measurement of the natural frequency of cedar cylinder wood were investigated.