This paper presents the validation of finite element model (FEM) of an
ultralight aircraft structure by using experimental modal analysis (EMA).
The main structure of ultralight aircraft consists of the wings, the fuselage and the empennage structures, which are fabricated by means of aluminum tubes through the bolts, rivets and the brackets. A commercial code, ANSYS,is used to establish the FEM. Normal mode analysis is performed to obtain the natural frequencies and mode shapes under a completely free boundary condition. EMA is conducted on the wings, the fuselage and the integral structures to obtain their natural frequencies and mode shapes, respectively.The FEM is then validated and updated according to the correlation of natural frequencies and mode shapes between EMA and FEA. It is essential to assure that the FEM is equivalent to the real aircraft structure for the further structural analysis.