Diagrid tube structures composed of straight diagonals with gradually varying angles

This paper presents preliminary design guidelines specifically for diagrid tube structures composed of straight diagonals with gradually changing angles. A graphic approach to configurating a diagrid of this type is introduced, with two basic geometric variables involved, i.e. the bottom and top diagonal angles. In terms of both stiffness and strength design criteria, a methodology for calculating diagonal member sizes is developed and applied to a set of diagrid tube structures with height-to-width aspect ratios ranging from 3.6 to 9. The diagrid tube structures are designed with various combinations of bottom and top angles in order to investigate the effects of bottom and top angles on the material usage. Based on the results, the optimal values of bottom and top angles are suggested, then, the optimal geometries for diagrid tube structures with different aspect ratios are determined. This paper attempts to help the designer arrange the structurally efficient diagrid layout conveniently and perform approximate calculations of the diagonal member sizes. Copyright © 2010 John Wiley & Sons, Ltd.