Optimization of elastomer layer in CLT panels for vibration reduction

Sammanfattning

In this thesis, optimization of cross-laminated timber panels is performed. A cross laminated timber panel consists of a set of wooden layers, which are bonded together. In this work, a layer of elastomer is included among the wooden layers. As the elastomer is a favourable material to improve the vibrational and acoustic properties, this thesis investigates how this material can be optimally distributed. The optimization of the panels specifically targets the elastomer layer, by distributing material to regions where it efficiently reduces the vibrational response. The response of the panels is analyzed by loading the panels with a harmonically varying force, where the forcing frequency is varied so that the vibrational response is evaluated over a range of frequencies. The vibrational response is then used as an objective function in an optimization problem with the constraint functions consisting of a volume constraint of the elastomer and the deflection of the panels due to static loading. As the configuration of the elastomer layer is of interest, topology optimization is employed to find a distribution of elastomer which ultimately yields a lower vibrational response than a uniform layer. The end result of the elastomer layer shows an interesting pattern where the mode shapes of the panel are reflected in the design, and the response is reduced in the range of 10-20%. The potential drawback may be that the eigenvalues appear at a slightly lower frequency.