Vibration-based numerical identification of effective orthotropic elastic properties for finite element model of cross-laminated timber panel

The influence of non-gluing of narrow surfaces of boards on all effective orthotropic elastic moduli for shell or solid finite element models of cross-laminated timber (CLT) panels is investigated. This lack of gluing leads to discontinuous layers and severe meshing difficulties. The objective of this study is to create an equivalent homogeneous layer and equivalent material properties in this case. Two finite element (FE) models were built for comparison. The first model, using solid elements, is the reference without gluing the narrow surfaces. The second considers homogeneous layers and equivalent material properties. Thanks to an identification process, all the elastic moduli of the model with homogeneous layers are adjusted to minimize the difference in vibration frequencies between the two models. A method is proposed to significantly speed-up the calculation of first derivatives, which are necessary for the identification process. The process was applied for 36 configurations of CLT panels with different geometrical properties (number of layers, width and thickness of boards) within the practical range. Metamodels are proposed to quickly calculate the effective moduli based on the vibration properties of CLT panels. The Verification and Validation methodology was applied to evaluate the performance of the two simplified FE models using the effective moduli.