Numerical simulations of the load bearing behavior of cross-laminated timber

Abstract

In the framework of presented thesis the two-step MCLT (Model for Cross Laminated Timber) is described. The main motivation for this thesis was to develop a simulation tool for investigation of the mechanical behaviour of cross-laminated timber and to apply it to studying the influence of varying mechanical characteristics of the individual lamellae on the overall plate behaviour. As the base for the MCLT one of the already existing two dimensional models - the KAREM model - is chosen. The first programme (simulation programme) generates the stiffness and strength values of each individual lamella of the plate, considering the material parameters, such as lengths of boards, density, knots and moisture content and their variations.<br />A plate with homogeneous mechanical properties is defined as reference plate. The second programme - finite element programme - computes the distributions of deflections, stresses and strains in the framework of elastic and elastic-plastic calculations. The results of computations performed for the reference plate, using the MCLT in the elastic range are compared with analytical results and show a good agreement. The MCLT can be used for estimating the stiffness and the elastic limit load of the plate. The elastic limit is determined for the reference plate and for one hundred plates with randomly distributed material properties. A considerable variation of this limit is observed. Considering the results of computations using MCLT, it is observed that the plasticisation and the lamination of layers affects the distribution of displacements, stresses and strains.<br />Also the variability of material parameters in the random plates influences the stiffness and elastic limit of the cross-laminated timber.