Investigation on the Acoustical Properties of Pinus Wood by Fixed- Flexural Vibration Testing

In this study the effect of clamping both ends of beam on the possibility of measuring acoustical properties (acoustical conversion efficiency, damping, and acoustic coefficient) of Scotch Pine (Pinus sylvestris L.) in both tangential and radial direction, by free vibration method has been studied. In accordance with ISO 3129 international standard, 19 visually clear wooden rectangular beams of Scotch-pine species with dimensions of 36×2×2cm (length× width×height) prepared under free vibration non-destructive tests. Effects of clamping of both ends of beam on the mentioned three factors with the results of this test in the case of free-free ends were compared. Clamping of both ends of beam increased vibration damping in comparison with bending test results. In associated with the acoustic coefficient, clamping of both ends of the beam had lower effect on this factor compared with free ends case also the results showed that there are no differences between free ends and fixed ends cases. But the results of estimating acoustical conversion efficiency in fixed end case indicated that the bending free vibration method in fixed end beam is an inappropriate method for evaluating this factor.