Elastic response of cross-laminated engineered bamboo panels subjected to in-plane loading

© ICE Publishing: All rights reserved. Novel cross-laminated bamboo panels comprising three and five layers (G-XLam3 and G-XLam5) were tested in compression along the main (0°) and the transverse (90°) directions. Linear variable differential transformer (LVDT) and non-contact three-dimensional digital image correlation (DIC) measuring techniques were used separately to measure deformation in the elastic region, and the elastic moduli, Ep C,0 and Ep C,90, were derived. Mean elastic modulus values obtained using LVDTs exhibited a good match with analytically predicted values. In contrast, the elastic values obtained by the DIC method were considerably higher and presented a considerable scatter of results. For instance, the Ep C,0 for G-XLam3 and G-XLam5 panels were 17·22 and 15·67 GPa, and 14·86 and 12·48 GPa, using the DIC and LVDT methods, respectively. In general, G-XLam panels with a fifth of the cross-sectional thickness and twice the density of analogous cross-laminated timber exhibited an approximately two-fold increase in Ep C,0 and Ep C,90. Overall, this research provides guidelines for the assessment and standardisation of the testing procedures for similar engineered bamboo products using contact and non-contact methods and highlights the potential of using G-XLam panels in stiffness-driven applications and in combination with wood for structural purposes

Vibration Characteristics of a Guitar Using Finite Element and Digital Image Correlation Techniques

The sound quality generated by a musical instrument depends on the vibration characteristics (i.e., natural frequencies and mode shapes) of the instrument. In this paper, a three-dimensional finite element model of a guitar was developed using quadratic shell and solid elements. An eigensolution was performed on the FE model to extract natural frequencies and mode shapes of the instrument. In order to validate the numerical results, a measurement was performed on the guitar using the digital image correlation technique. In this measurement, the guitar was placed in a free-free configuration and was excited using a broadband excitation generated by a sound source. The response of the guitar to the excitation was recorded using a pair of high-speed cameras. The recorded images were processed in a digital image correlation program to extract its natural frequencies and mode shape. The results show a strong correlation between the numerical model and experimental results