Investigation of Wood Mechanical Properties by the Resonance Vibrations Method

Abstract

The mechanical properties of wood polymeric system are defined in terms of viscoelastic materials. The response of viscoelastic bodies to external effects depends on the ratio of elastic and viscous properties. These properties have an impact on relaxation processes for both wooden specimens and wooden articles. In this paper the method of estimation of dynamical modulus of elasticity and coefficient of damping based on resonance vibration is presented. Fir timber specimens have been used in the investigation. The specimens were sawn from three places of the log and they were relatively called “but-end” “center” and “top”. The highest modulus of elasticity was determined in the specimens from the butt-end of a log, the lowest was in the specimen from the center part. The variation of the coefficient of damping was found to be inversely proportional to that of the value of the modulus of elasticity.