Bend Torsion Analysis Of Multicellular Thin-walled Box Girder Considering Distortion

Along with the advance of architectural design and construction technique, thethin-walled box girder with its good space overall mechanical performance is more andmore widely used in bridge engineering, marine engineering, high-rise buildings, heavyworkshop, and rail transit construction process. Under eccentric load, however, thethin-walled box girder will happen not only bending and twisting, also lead to thedistortion effect. Engineering practice and theoretical research show that the negativeimpact of the distortion effect of the thin-walled box girder is not to be ignored. And thestress of the thin-walled box girder is a more intricate issue, and thus the relevantacademic calculations is still not very well. And now, with the construction of a largenumber of bridge of big traffic flow, a lot of multi cellular box girders appeared.However, the existing literature mainly is the study of the single chamber box girder,less research on the multicellular box girder. So in order to master the properties of thebending and twisting of the thin-walled box girder and find out the stress and thedeformation of the box girder under the action of bending and twisting whenconsidering the distortion, it is necessary to explore the multicellular thin-walled boxgirder at a deeper level and establish the corresponding analysis method.Based on the Lagrange equation and Hamilton dual solution system, this paperapplied the assumption of the method of generalized coordinates, in view of thedistortion effects, and analyzed the mechanical performance of multicellular thin-walledbox girder in bending and twisting. Starting from the total potential energy of thestructure, this paper first derived the Lagrange function. The problem is translated fromthe Lagrange system to the Hamiltonian dual system by means of introducing the dualvariables. Then the paper established the Hamilton canonical equation of themulticellular thin-walled box girder bending and twisting when considering thedistortion, and combined with the precise integration method for the boundary valueproblem on both ends to analyze it, through programming and debugging thecorresponding MATLAB analysis program obtained the precision numerical solution ofthe system. Getting the warping displacement, distortion angle, twist angle and otherimportant information, it can easily draw the normal stress distribution graph ofmulticellular thin-walled box girder under the action of the bend torsion. And on this basis, this article established the motion equation, and analyzed the natural vibrationcharacteristics of the structure. The results showed the correctness of the Hamiltoncanonical equation and the applicability of the precise integration method.Although this article studied for the classic problem of elastic theory, but theproposed calculation model of multicellular thin-wall box girder bending and twistingconsidering the distortion effects is more close to the real deformation of thecomponents. And the establishment of Hamilton canonical equation and the applicationof the precise integration method is innovative.The method is suitable for the differentsupport conditions of bend torsion analysis of multicellular thin-walled box girder. Notonly its form is simple, but the amount of calculation is small. This provides a newsimple method and means to solve such problems in the engineering. It is of theoreticalsignificance and engineering practical value and makes the structural analysis frommechanical expression form to mathematical expression form, and provided thereference data for the understanding of this kind of structure.