This paper presents an analysis of the influence of inconsistent boundary conditions on critical buckling loads of geometrically perfect two-layer Euler elastic columns with inter-layer slip between the layers. The analysis in based on the linearized stability theory. The theoretical and parametric study prove the interrelation of boundary conditions in longitudinal and transverse directions. The influence of the inconsistent boundadry conditions on the buckling loads of two-layer Euler columns can be up to 20 %.
COBISS.SI-ID: 5069153
A mathematical model for structural behavior of timber columns under fire has been proposed. The semi-analytical study has been carried out for evaluating the load-carrying capacity of timber columns exposed to fire. Particular emphasis has been given to critical buckling loads. For this purpose, a parametric study has been performed by which the influence of slenderness ratio, load level, and water content on critical buckling loads of timber columns have been investigated. The results of this preliminary study showed that the present semi-analytical method is conservative compared to the two simplified calculation methods offered by Eurocode 5 if the transfer of water is neglected, while, on the other hand, the results agree well for a water content of 12%. Moreover, for higher water contents, the present semi-analytical model is non-conservative compared to the Eurocode 5 methods.
COBISS.SI-ID: 5504097
A mathematical model for a slip-buckling problem has been proposed and its exact solution has been found for the analysis of materially inelastic two-layer composite columns with non-linear interface compliance. The mathematical model has been carried out to evaluate exact critical buckling loads. It has been demonstrated mathematically exactly, that exact critical buckling loads are influenced by the initial stiffness, and hence on linear portion of the interface force-slip relationship. Besides, it has been shown that material inelasticity can reduce the critical buckling loads significantly and that the interlayer stiffness has an important effect on the transition between the elastic and inelastic buckling
COBISS.SI-ID: 5522529
This paper presents an efficient mathematical model for studying the buckling behavior of geometrically perfect elastic two-layer composite columns with interlayer slip between the layers. The present analytical model is based on the linearized stability theory and is capable of predicting exact critical buckling loads. Based on the parametric analysis, the critical buckling loads are compared to those in the literature. It is shown that the discrepancy between the different methods can be up to approximately 22 %. In addition, a combined and an individual effect of pre-buckling shortening and transverse shear deformation on the critical buckling loads is studied in detail. A comprehensive parametric analysis reveals that generally the effect of pre-buckling shortening can be neglected, while, on the other hand, the effect of transverse shear deformation can be significant. This effect can be up to 20 % for timber composite columns, 40 % for composite columns very flexible in shear (pyrolytic graphite), while for metal composite columns it is insignificant.
COBISS.SI-ID: 5249121
The paper presents a semi-analytical method for computational assessment of times-to-failure and critical temperatures of timber columns exposed to fire. The method is based on the 2D thermo-mechanical analysis, in which a moisture-thermal state of columns is modeled by Luikov equations and, on the other hand, the exact mechanical analysis including buckling behavior of columns, which is modeled by linearized Reissner’s kinematic equations. The model predicts the char formation in the timber column as a function of its temperature, moisture content, and density. As a result, critical temperatures and times-to-failure of charred timber columns exposed to fire are calculated for different exposure times, different dimensions of the column and different temperature-dependent thermo-mechanical parameters.
COBISS.SI-ID: 5069409