Bending of Three-Dimensional Pantographic Column

A basic scissor-like element (SLE) consists of two bars connected at their intermediate points by a shear resisting pivot. This pivotal connection, allowing relative rotation of the bars in the plane formed by their axes, is the characteristic feature of pantographic deployable structures. Such structures include plane and spatial columns and arches, flat slabs, domes and other arrangements. The behaviour of straight two-dimensional pantographic columns in bending was considered by Raskin and Roorda (1998). The assumptions of linearity and negligible axial deformations of bars led to the compact expression for the equivalent bending stiffness: 6EIsinγ, where EI is the bending stiffness of bars and γ is the degree of deployment equal to the angle between the axes of the bars and the ground.