Effects of localized imperfections on compressive strength of long rectangular plates

This paper describes a data-base approach to the ultimate compressive strength of unstiffened plates loaded in uniaxial compression. A total 793 individual test results of plates is surveyed and stored into the Numerical Data-Base for the Ultimate Strength of Steel Structures (NDSS). Statistical assessments are made for the plate test results to compare with the available strength formulas. And the effects of initial imperfections such as residual stress and initial out-of-flatness are discussed. Then strength formulas are proposed for two groups, “with residual stress” and “without residual stress”. to explain more accurately the test data.

Basic compressive strength of steel plates from test data

Two analytical approaches are used to investigate the effect of curvature on the elastic local buckling behavior of horizontally curved I-girder compression flanges. First, a governing differential equation for the isolated curved flange plate elements under various loading and boundary conditions is derived in polar coordinates and the equation is solved using the finite-difference technique. Numerical results for various curvatures and aspect ratios are generated. Second, the finite-element method using MSC/NASTRAN is used where the entire cross section of the curved I-girder is modeled. A comparison of the results from the two approaches is made and differences are explained. The effect of curvature on the elastic buckling of the flange plates is observed and a simple but conservative formulation representing this effect is derived for design use.

Local Buckling of Curved I-Girder Flanges

The combined finite elementtransfer matrix method is applied to elasticplastic problems with large displacements In the calculation program developed in this paper, the same procedures as those us

Seiji Miyazaki

Papers

Elastic-plastic analysis of compressed plate with residual stress and initial deflection