Static and Dynamic Modeling and Analysis of Tube Frames

Tube frame structures subjected to static or dynamic loads are usually analyzed by the finite element method in which the structure is represented by a large system of equations. This method, however, requires extensive alculations and considerable efforts in data preparation and output interpretation. The paper presents an approximate method in which the tube structure is represented by a continuum. The model considers the shear‐lag effect, which is significant in tube structures, as well as shear and flexural deformation. The continuous model is then represented by a set of first‐order differential equations. They are solved numerically using a fourth‐order approximation technique, and the results compared to results of finite element code. The resulting deflection, frequencies and mode shapes predicted by the continuous model show excellent comparison to the finite element results.