Structural optimization of a joined wing using equivalent static loads

Abstract

The joined wing is anew concept of the airplane wing. The forewing and the aft wing are joined together in a joined wing. The range and loiter are longer than those of a conventional wing. The joined wing can lead to increased aerodynamic performance and reduction of the structural weight. In this research, dynamic response optimization of a joined wing is carried out by using equivalent static loads. Equivalent static loads are made to generate the same displacement field as that from dynamic loads at each time step of dynamic analysis. The gust loads are considered as critical loading conditions and they dynamically act on the structure of the aircraft. It is difficult to identify the exact gust-load profile; therefore, the dynamic loads are assumed to be a one-cosine function. Static response optimization is performed for the two cases: one uses the same design variable definition as dynamic response optimization, and the other uses the thicknesses of all elements as design variables; the results are then compared.