FLAT BENDING SHAPE STABILITY OF RECTANGULAR CROSS-SECTION WOODEN BEAMS WHEN FASTENING THE EDGE STRETCHED FROM THE BENDING MOMENT

Abstract

: the article presents the solution to the problem of calculating the lateral buckling of wooden beams with a narrow rectangular section, taking into account intermediate point fixing in the edge stretched from the bending moment. The structure is considered as an orthotropic plate, the calculation is performed by the finite element method (FEM). To obtain a result that is valid for any beam geometry, the system of FEM equations is re-duced to a dimensionless form. The dimensionless parameter that determines the value of the critical load is calcu-lated based on the solution of the generalized eigenvalue problem. The numerical calculation algorithm is imple-mented in the MATLAB environment. The developed technique is verified by comparison with calculations in the LIRA and ANSYS software systems using flat and volumetric finite elements. A comparison is also made with the calculation formula presented in the Russian design standards for wooden structures SP 64.13330.2017 for the coefficient, taking into account intermediate fixing, with pure bending. It has been established that this dependence rather roughly takes into account the fastening from the bending plane of the edge stretched from the bending moment. Using the package Curve Fitting Toolbox of the MATLAB environment, we have selected refined formula for the coefficient, which can be used in engineering calculations.