1 Application of Lattice Spring Models for Shell Structures Report 2016 – The Elastic Shell Ioannis Doltsinis, Rafael Jarzabek, Michael Reck Institut für Statik und Dynamik der Luft- und Raumfahrtkonstruktionen, Universität Stuttgart Vitor Dias da Silva Departamento de Engenharia Civil – FCTUC, Universidade de Coimbra Introduction A number of arguments may suggest that solid continua could be investigated with spring cell substitutes instead of finite elements. The main arguments would be a simplified discrete representation, microstructural modelling, uniaxial material laws, the resolution of progressing damage and failure. However, the facts damp the high expectations. Only specific continua can be represented by spring cells. There is considerable contemporary research being done on Lattice Spring Models. The initiative work has been performed by Hrennikoff [1]. In contrast to the representation of solid continua by spring grids also grid structures were analysed by continuum methods [2]. Given the non-exhaustive state of the art, two complementary doctoral dissertations at the ISD in Stuttgart are devoted to the spring cell substitution of continua. One aims at defining the limits of the approximation of defective bar-spring models, the other extends to a rigorously condensed representation of the continuum by introducing additional angular springs. An advanced stage of the research work [3] [4] was exposed and discussed at the international ECCOMAS 2016 Congress in the framework of the thematic session “Spring Lattice Models for Linear- and Nonlinear Continua”. The report on the work performed at Coimbra University on the grid generation and stress analysis of shell structures [5] completed the available background as the starting point of the scheduled DAAD project. Also of interest was the diverse approach to spring cells based on the natural representation of the elastic continuum [6]. The project “Einsatz von Stabgittermodellen für Schalentragwerke - Employment of Spring Lattice Models for Shell Structures” was conceived for investigating the utility of the ISD spring cell models in the context of shell structures, and for proving them against the expertise available at Coimbra University. The first of the two year project deals with the elastic shells, the subject of the present account. Apart from membrane shells, the investigations also deal with the modelling of shell structures with bending stiffness. A specific programme implementation of the spring models is used at the ISD, whereas Coimbra relies on the Finite Element Programming System – FEPS [7] developed in Stuttgart.