DIANA is described as 'Extensive multi-purpose finite element software package that is dedicated, to a wide range of problems arising in Civil engineering including structural, geotechnical, tunnelling, earthquake disciplines and oil & gas engineering' and is an app. There are more than 50 alternatives to DIANA for Windows, Web-based and Linux. The best DIANA alternative is Robot Structural Analysis Professional. It's not free, so if you're looking for a free alternative, you could try SkyCiv or Resultant. Other great apps like DIANA are Abaqus Unified FEA, CloudCalc, RISA-3D and midas Civil.