28th INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES NEOCASS: AN OPEN SOURCE ENVIRONMENT FOR THE AEROELASTICANALYSIS AT CONCEPTUAL DESIGN LEVEL L. Cavagna § - A.De Gaspari § - S. Ricci § - L. Riccobene § - L. Travaglini § § Dipartimento di Ingegneria Aerospaziale, Politecnico di Milano Keywords: conceptual design, aeroelasticity, unsteady aerodynamics, Computer Aided Design TOPIC AREAS: Material and Structures - Structural Dynamics and Aeroelasticity Abstract This paper, after a brief introduction describing the NeoCASS suite for aircraft conceptual design, reports the recent developments introduced into the software. Typical examples of results obtain- able using NeoCASS are also reported. 1 Introduction It is well known the importance to be able to pre- dict as early as possible the performances of a fu- ture aircraft and to study quickly but accurately a wide range of designs at conceptual stage before going to further steps such as the preliminary and detailed ones when the design freedom is con- siderably restricted. Most of the life-cycle cost of an aircraft is incurred during the conceptual design phase and therefore, the earlier an appro- priate conceptual morphology can be found, the more economical the whole design process will be, avoiding costly later redesign and corrections. Conceptual design systems nowadays adopted for the design of contemporary com- mercial aircraft make extensive use of handbook methods based on semi-empirical theory and data. Although these techniques are now well proven and developed, they are not exhaustive and, considering today’s computer performances, it is now conceivable to bring higher fidelity methods earlier in the design process. From 2006 to 2009 a research project funded by the 6th European Research Framework named SimSAC (Simulating Aircraft Stability And Control Char- acteristics for Use in Conceptual Design) aimed at this goal, i.e. the development of a design tool based on multi-fidelity semi-empirical, computational and analytical methods for the aero-structural analysis of an aircraft layout at conceptual design stage, called CAESIOM. Inside CEASIOM tool, a dedicated suite for the structural sizing and aeroelastic analysis, named NeoCASS (Next generation Conceptual Aero-Structural Sizing Suite) has been developed by the Department of Aerospace Engineering of Politecnico di Milano, having the following main goals: to provide a more realistic estimation of structural weight; to allow for aeroelastic analysis and optimization since the conceptual design level. The geometrical representation of the aircraft adopted by CEASIOM and by NeoCASS as well, is fully described by a unique parametrization file based on the Extensible Markup Language (XML) format to which all different analysis modules refer. The geoemtry database is easily generated and managed in a visual environment by a dedicated module, named AcBuilder. The adopted format allows storing each component of the aircraft and its parameter in a hierarchical and sorted way. It eases data sharing as well as the expansion of the dataset, i.e. the number of components of the aircraft can be modified at will by introducing new components as well as new parameters, thus increasing the family of morphologies that can be modeled. After the end of SimSAC project the devel- 1