CONTINUUM MODELS FOR BEAM- AND PLATELIKE LATTICE STRUCTURES

A general procedure for determining beam and plate properties for beam- and platelike lattice structures is presented. In the literature several methods for the calculation of the equivalent stiffnesses of lattice structures exist. In this document an energy approach is used to derive explicit expressions for the equivalent stiffnesses of the most common types of plane trusses. Plane trusses can be combined to form threedimensional beamlike structures: based on the results of the plane trusses, the equivalent continuum properties of threedimensional beam elements, like the bending stiffnesses, the shear stiffnesses, the torsional stiffness, the position of the shear centre can be determined. Finally it is shown that platelike lattice structures can be modelled with Mindlin plate elements which incorporate bending as well as shear deformation. The approach is compared with an energy based method found in the literature. The accuracy of the continuum models is demonstrated by a number of representative examples.