DIANA FEA  DIANA (acronym DIsplacement ANAlyser) is a Finite Element Analysis (FEA) solver developed and distributed by DIANA FEA BV (previously TNO DIANA BV) and several other resellers worldwide. The software is utilised at both ends of the market, by small consultancies and global engineering consultants, research institutions and is utilised by many highly respected educational institutions worldwide in both civil and geotechnical engineering courses. DIANA is equipped with very powerful solvers which enables the analysis of a wide range of structures, large and small - with basic or advanced analyses. A large selection of material models, element libraries and analysis procedures are available within the package which gives DIANA a large degree of flexibility. The main fields of use of DIANA include design and analysis of dams & dikes; tunnels & underground structures; oil & gas & historical constructions and large reinforced concrete structures. Some of the specialised analyses available in DIANA for these fields of use include seismic analysis; fire analysis and young hardening concrete. TNO (Netherlands Organisation for Applied Scientific Research) originally authored the code, upon which the DIANA FEA BV flagship software “DIANA” is based, in 1972. The initial idea had been to develop an in-house code for consultancy work in the field of concrete mechanics and civil engineering. This code was based on the displacement method, and was called “DIANA” – an acronym for DIsplacement ANAlyser. By 1975, DIANA was being used for the analysis of a number of complex off-shore structures in the Netherlands. Experience gained from these projects led to the realisation that in order to model, mesh and analyse large reinforced concrete structures in a streamlined fashion (and within one package), a huge amount of processing power would be required. At that point TNO started to invest in not only developing the DIANA software but also in the purchase of, what was then, up to the minute computing equipment. In the following years, TNO continued to expand the limitations of the DIANA software, introducing MESH for automatic mesh generation and GRAPHI to display the model and analysis results. In 1977, DIANA was used to analyse parts of the Oosterschelde Deltawerken in Zeeland, the Netherlands. By this time, the amount of time required to carry out analyses had significantly decreased, and DIANA was becoming increasingly recognised for its capabilities.