Study On The Influence Of Initial Imperfections To The Stability Of Stiffened Plates On The Large Influe Structure

With the development of society, the steel structure are applied in all kinds ofconstructions、buildings、ships and so on. There are many uncertain factors inengineering. To conform to specified requirements、safety and durability, initialimperfections are considered in the process of the design and installation. Thenthe influence of initial imperfections to safety is analyzed which can improvemethods of design and construction technologies. The safety can be evaluatedobjectively.In this thesis, the whole static of flue, reactor and brackets were calculatedusing finite element analysis software ANSYS. Based on the building designed byBeijing State Power, the week stiffened plates of flue was calculated by usingfinite element analysis software ANSYS. Considering initial infections, theinfluences of the sizes of initial infections on the stability of plates were anlayzed.As for the plates of the roof, it is concluded that the bigger the initial infectionsare, the smaller the stability of plates are. What’s more, the thicker plates are, theweaker the influence of initial infections on stability is. Besides, changing thekind of stiffened, the non-linear buckling of the flat steel is the largest. Then thefollowing are the angle steel、channel-section steel and I-beam. For a/b, whena/b=1, the largest stress occures in the coner of the plate. While a/b=2and a/b=3,they are in long sides. In the end, the bigger the hole is, the smaller the stress is.When the ratio of the open hole is0.8, the non-linear stress is40%times smallerthan that of0.2.In addition, skew plates are analyzed. With the changes of the angle, thebending moments of longitudinal stiffeners are diffierent. And whatever the sizeof the angle is, the bending moment is parabolic. The transverse stiffener is thewave. Nomatter a/b is, the buckling make smaller. Influence of initial infectionson skew plates of45°、60°、75°are weaker. But it is obvious for90°. Whena/b=2.25, the buckling stress with initial infection is14.75%times smaller thanthat without initial infections. At last, the bigger the initial infections are, thesmaller ultimate bearing capacity is. The capacity of the plate is strong.