Methodology for Supersonic Panel Flutter Analysis of Thermal Protection System Seals

Abstract

A methodology is presented for the e utter analysis of the seal of the thermal protection system panel of the X-33 Advanced Technology Demonstrator test vehicle. The seal is simulated as a two-dimensional cantilevered panel with an elastic stopper, which is modeled as an equivalent spring. This cantilever beam ‐spring model under the aerodynamic pressure at supersonic speeds becomes an impact nonlinear dynamic system. The e utter analysis of the seal is, thus, carried out using time-domain numerical simulation with a displacement stability criterion. The e utter boundary of the seal is further verie ed with a family of three traditional and one nontraditional panel e utter models. The frequency-domain method that applies eigenanalysis on the traditional panel e utter problem was used. The results showed that the critical dynamic pressure could be more than doubled with the properly chosen materialforthebase stopper. Theproposed methodology can beeasily extended to three-dimensional panel seals with e ow angularity. Nomenclature [aa], [Aa] = element and system aerodynamic ine uence matrices b = beam width Ca = aerodynamic damping coefe cient fdg = element nodal displacement vector E = Young’ s modulus Fe