Cantilever-beam dynamic modulus for wood composite products. Part 1, apparatus

Free vibration of both-ends clamped wooden beams: is it potentially applicable as an in situ assessment method?

“…Considerable errors in shear deflection and rotary inertia in both-ends clamped flexural vibration make the modulus of elasticity hard to obtain in flexurally excited beams with similar ending conditions. While the effects of shear deflection and rotary inertia on dynamic modulus evaluations have been eliminated for free-free and cantilever beams in flexural vibrations (Harris and Piersol 2002;Turk et al 2008), investigations on the both-ends clamped condition are in progress by the present research team. It was also indicated that altering gripping forces would change the resonance frequency in both-ends clamped beams to a considerable extent (Kubojima et al 2012).…”

An Estimation of Dynamic Modulus of Elasticity in Cantilever Flexural Timber Beams

“…Therefore, if care is taken to control the ratio of thickness divided by free length, the radius of gyration divided by free length (Equation (2)) is <0.005 (dimensionless), and the frequency correction factor approaches 1.0 where shear and rotary effects are negligible (Turk et al, 2008).…”

“…However, the application of this equation is limited to some proper l/h ratios (greater than 20 in a free-free condition or greater than 58 in a fixed-free condition). To determine the relative magnitude of shear force in terms of the idealized solution in a fixed-free isotropic beam, Timoshenko introduced a set of curves to obtain the correction factor defined by the radius of gyration and free length (Harris, 2002;Turk et al, 2008) (Fig. 1).…”

“…To determine the relative magnitude of shear deflection in terms of an idealized solution, Timoshenko defined a correction factor as the radius of gyration divided by free length in which the correction coefficient depended upon the ratio of specimen thickness to specimen length (Harris, 2002;Turk et al, 2008). Timoshenko presented a set of curves to determine the correction factor in six initial modes of flexural vibration.…”

Comparison of Wood Composite Properties Using Cantilever-Beam Bending

“…While the small width of the beam may introduce some edge affects that would influence the properties of a wider beam, the relative differences between properties should be similar and thus important to determine. This study is part of a larger program to investigate the use of the cantilever beam test method for determining various material properties for wood-based composite materials (Turk et al 2008;Zhang et al 2010;Hunt et al 2013;Zhang et al 2014;Hunt et al 2015). Further research will compare results from standard bending tests, and correlate those with the square beam.…”