Generalized Methods for Aeroelastic Analysis

Abstract: Generalized aeroelastic methods are here defined as methodsthat allow aeroelastic analysis of problems in many engineeringdisciplines. Aeroelastic/fluid-elastic phenomena are ofsignificant importance in many industrial applications, but fewtools exist for efficient analysis of these systems. In theaeronautical world, methods that neglect wing thickness andassume slender body for non lift generating bodies areutilized. These methods also use zero incidence flow conditionsas equilibrium condition. Except for acoustic problemsbasically only nonlinear methods that have emerged during thepast few years exists for general applications. These nonlinearmethods are generally very inefficient for the study ofproblems involving high frequencies.In the framework of the project reported here, a method/toolhas been developed to perform efficient aeroelastic analysis ingeneral applications. The selected approach makes it possibleto simulate systems that cannot be approximated by neglectingthickness of the structure. The numerical boundary elementmethod has been used to discretize the steady and unsteadyvelocity potential equation that is used as mathematical modelof the fluid dynamics. The use of the boundary element methodenables unstructured meshes to be used on the fluid-structureinterfaces. Applications ranging from Micro Electro-MechanicalSystems to large scale systems can be analyzed. The method, asa subset of the aeroelastic capabilities also, enablesefficient analysis of flow fields, acoustics and acoustics inflow fields. By combining the developed linear method withnonlinear tools and/or measurements it is possible to create anunderstanding of the behaviour of very complex problems.A summary of the method is presented in the introduction ofthis thesis. Additionally the influence of wing thickness onthe aeroelastic characteristics of the bending-torsion mode forthe so called BAH-wing has been studied.