On the use of the P-TFE method for panel flutter optimization

A numerical approach for structural analysis based on the concept of parame ter transfer finite elements (P-TFE) was proposed by the authors in previou s papers Barboni R, Castellani A, Mannini A. Un metodo analitico-numerico p er l'analisi strutturale. Atti del Dipartimento Aerospaziale, Roma, Novembr e, 1988; Barboni R, Gaudenzi P, Mannini A, Santini P. An application to the dynamics of large space structures of a new semi-analytic method for struc tural analysis. 17th Congress ICAS, Stockholm, September, 1990; Barboni R, Gaudenzi P, Mannini A. Parameter-transfer finite element method for structu ral analysis. AIAA Journal 1993; 31:923-9; Barboni R, Mannini A, Scarponi C . Structural optimization with parameter-transfer finite element. Meccania 1995; 30: 291-304. Such elements are able to take into account, like a tran sfer function, the whole behaviour of the structure under concern, subject to dynamic, aerodynamic or thermal actions, and to produce, in analogy with the finite element method, a numerical technique of discretization of a co ntinuum. The purpose of this paper is to apply this methodology to optimization prob lems, in particular to the design of a minimum-weight monodimensional panel under critical flutter pressure constraint. The use of P-TFE in this aeroelastic optimization problem overcomes most di fficulties of the usual techniques of solution, in particular, the evaluati on of the sensitivity matrix, the terms of which can be calculated analytic ally in the frame of the proposed approach. Moreover, the critical conditio ns are directly imposed by the solution of a non-linear system of two equat ions in the eigenfrequency and the dynamic pressure unknowns. Several examples relevant to different boundary conditions are presented an d the results compared with those obtained by other authors, using differen t methodologies. (C) 1998 Elsevier Science Ltd. All rights reserved.