Study on stability of double corsair's main stand
The structure safety is numerically studied on main support of the huge pirate ship by use of finite element method (FEM). In order to the elements meshed successfully, the equivalent treatment is used for the complex structure. The static, structure instability and model analyses are carried out. The static and stability safe coefficient are 6.12 and 19, respectively, which are more than the demand in national standard. The model analysis indicates that the swing frequency is 0.08 Hz, and can be kept off the natural frequency.
Thin-walled structures with slotted connections stability problems
Abstract In this paper the linear and non-linear stability analyses of elastic structures with unilateral supports or connections are presented. Local and global buckling phenomena are analysed for a wide range of columns’ lengths to encounter coupled instability, which appears when local buckling occurs close to global one. Influence of clearances on buckling and post-critical response is examined. This phenomena is illustrated using simplified models, where the clearances are introduced as translation or rotation gaps. Main attention is focused on modelling the double sigma members, where the cross-sections are composed of two sigma members, connected in discrete points distributed along the webs. The influence of spacing and way of numerical modelling of connectors on buckling behaviour of beams is studied. Numerical examples illustrate the importance of proper modelling of the structures with slotted connections accounting for initial imperfections. The examples are solved using FEM.
The effect of nonlinear restraint on torsional buckling and post-buckling behaviour of a thin-walled column
Torsional buckling and post-buckling of a simply supported axially compressed thin-walled column of open bisymmetric cross-section with a central restrain has been investigated. The nonlinear behaviour of the restraint against the rotation angle of the cross-section has been assumed. The stability consideration is based upon the classical theory of beams with nondeformable cross-section. The solution of the buckling and post-buckling behaviour problem formulated has been found with the perturbation approach. The critical load and the initial post-buckling path of equilibrium for I – column for the cubic relation of the restraint reaction and the rotation angle have been determined. The results show the considerable effect of nonlinearity of the restraint behaviour on the post-buckling path of equilibrium of the column in comparison with the linear restraint.