Geometric imperfections such as radial imperfection, diamond shape, and local dimples could affect the buckling mode and load carrying capacity of axially compressed steel tubular columns. This paper experimentally investigates the effect of radial imperfection on the load carrying capacity of tubular columns. Test samples include 100 specimens with different values for diameter, length, thickn...

One of the common failure modes of thin cylindrical shell subjected external pressure is buckling. The buckling pressure of these shell structures are dominantly affected by the geometrical imperfections present in the cylindrical shell which are very difficult to alleviate during manufacturing process. In this work, only three types of geometrical imperfection patterns are considered namely (a...

PANDA2, a computer program for the minimum-weight design of elastic perfect and imperfect stiffened cylindrical panels and shells under multiple sets of combined loads, is used to obtain optimum designs of uniformly axially compressed elastic internal T-ring and external T-stringer stiffened cylindrical shells with initial imperfections in the form of the general buckling mode. The optimum desi...

In this paper, individual and combined effects of distributed and local geometrical imperfections on the limit load of an isotropic, thin-walled cylindrical shell under axial compression are investigated. First eigen affine mode shape imperfection pattern (FEAMSIP) is taken as distributed geometrical imperfections and dent as local geometrical imperfections. Limit load of the cylindrical shells...

The initial postbuckling behavior and imperfection sensitivity of truss-type structures in which the joints do not transmit moments is determined by means of the Lyapunov-SchmidtKoiter approach. Such structures possess local buckling modes involving the buckling of individual members, and global modes involving axial deformations of all members but no member buckling. Of particular interest is ...

Abstract: Consistent Imperfection Mode Method (CIMM) is a widely-used and effective numerical method to study the buckling capacity of spatial structure. CIMM used an “artificial” deformation instead of “artificial” load eccentricity to imitate the initial disturbance/imperfection for calculation of buckling load, and the basic mode obtained from linear buckling analysis could be used to simula...

Perfect graphs constitute a well-studied graph class with a rich structure, reflected by many characterizations with respect to different concepts. Perfect graphs are, for instance, precisely those graphs G where the stable set polytope STAB(G) coincides with the fractional stable set polytope QSTAB(G). For all imperfect graphs G it holds that STAB(G) ⊂ QSTAB(G). It is, therefore, natural to us...