Analysis Of Shear Lag Effect In Thin-walled Box Girders With One-dimensional Discrete Finite Element

This dissertation establishes numerical methods in structural analysis on the basic of variation principle, finite member element method, spline function, etc. And the computation methods of thin-walled structures are studied systematically. The method of one-dimensional discrete finite member element and the spline Ritz method are proposed, and these methods are applied to the analysis of shear lag effect in thin-walled structures on the static and vibration.For the parts of static analysis, based on the theories of thin-walled bars theory and the variation principle, consider of shear lag effect, one-dimensional discrete finite element and spline Rize method are used to derive the calculation formulas of analysis of shear lag effect in thin-walled box girder. According to these formulas, the author especially studied the shear lay effect in box girder with constant and varying depth, and also studied thenegative shear lag in Cantilever Box Girder with constant and varying depth.Based on the Hamilton's principle and the displacement variation principle, one-dimensional discrete finite element method is developed for vibration analysis of thin-walled members. The analysis takes into account the effect of shearing strains of the middle surface of walls on the vibration, which reflects the shear lag phenomenon.To verify the accuracy and efficiency of these proposed method, then the concerning programs are worked out w;>1 ^ ORTRAN languages. The present results are compared with those obtained using other methods in reference.