Nonlinear supersonic flutter analysis of reinforced laminated curved panels

Author(s)

Myrella Vieira Cabral

• Document type: Master's Dissertation
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2021-04-26

Examining board members

Flavio Donizeti Marques; António Joaquim Mendes Ferreira; Domingos Alves Rade

• Advisor: Flavio Donizeti Marques

Abstract

The self-excited aeroelastic instability of thin plates or shells in the supersonic regime is called panel flutter, which may cause severe structural failure in aircraft and spacecraft. Thus, a reliable modeling of such phenomenon is crucial for safely predicting the lifespan of aircraft skins. Indeed, aeronautical skins are typically composed of large internally reinforced panels. The presence of the stiffening components subdivides the panel into several cells, which may interact structurally. However, the ample majority of published studies concerning the aeroelastic behavior of shells and plates treats each skin panel as an isolated structure. In this context, the present research project aims to investigate the effects of the structural coupling between the multiple curved panels and to assess the inaccuracies of the single-panel model by systematically comparing its results with those from the current multibay model. Moreover, the curvature effects will also be investigated. To do that, the Mindlin shallow shell theory coupled with the nonlinear von Kármán strains was applied. For the aerodynamic model, the first-order piston theory is applied, which is suitable for high-supersonic flows. The energy equations are discretized through the Finite Element Method, and the resulting aeroelastic equations of motion are solved in the time domain by using a Newmark integration method. The final algorithm is verified and validated through comparison with numerical and analytical solutions from the literature and with the commercial finite element software, ABAQUS. Symmetric and asymmetric composite laminated double cylindrical panels with different curvature ratios were analyzed for the streamwise and cross-stream configurations concerning the supersonic flow direction. Therefore, the effect of curvature, flow direction, and lamination scheme in the pre- and post flutter behavior of curved cylindrical panels were investigated. (AU)

• FAPESP's process: 19/11309-9 - Supersonic aerothermoelastic nonlinear flutter analysis of reinforced laminated curved panels
• Grantee: Myrella Vieira Cabral
• Support Opportunities: Scholarships in Brazil - Master