THE COMPOUND SPLINE FINITE STRIP METHOD FOR THE ELASTIC STABILITY OF U AND C BUILT-UP COLUMNS

摘要

Using the basis of the spline finite strip method, we propose a "compound" spline method to study the elastic stability of axially compressed battened columns composed of U and C shaped channels. These channels are modelled with spline finite strips while the connecting elements are represented by a twelve degrees of freedom beam finite element which its stiffness matrix is modified in order to ensure complete compatibility with the strips. First of all, the effect of the batten plates number on slender U and C columns has been examined Then, fixing the number of batten plates, a stability analysis was conducted. The aim is to study the variation of the critical stress and nature of the associated buckling mode with the column length. Finally, elastic stability curves for U and C built-up columns were proposed for practical use.