The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical ...The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.展开更多
The design of the re-entry space vehicles and high-speed aircraft structures requires special attention to the non-linear thermoelastic and aerodynamic instabilities.The thermal effects are important since temperature...The design of the re-entry space vehicles and high-speed aircraft structures requires special attention to the non-linear thermoelastic and aerodynamic instabilities.The thermal effects are important since temperature environment influences significantly the static and dynamic behaviors of flight structures in supersonic/hypersonic regimes.The dynamic behavior of a double-wedge lifting surface with combined freeplay and cubic stiffening structural nonlinearities in both plunging and pitching degrees-of-freedom(DOF) operating in supersonic/hypersonic flight speed regimes has been analyzed.In addition a third order piston theory aerodynamics(PTA) is used to evaluate the non-linear unsteady aerodynamic loads applied to the wing section.Loss of torsional stiffness that may be incurred by lifting surfaces subjected to axial stresses induced by aerodynamic heating is also considered.The aerodynamic heating effect is estimated based on the adiabatic wall temperature due to high speed airstreams.It is demonstrated that serious losses of torsional stiffness may occur in such lifting surfaces;the influence of various parameters such as flight condition,thickness ratio,freeplays and pitching stiffness nonlinearity are discussed.展开更多
基金Project supported by the Science Foundation of Shanghai Municipal Commission of Education (Grant No.98AJ01)the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology (Grant No.03ZR14032)
文摘The dynamic response of a flexible spinning vehicle with the varying thrust was investigated. The varying thrust was modeled as a series of simple harmonic components superimposed on a constant thrust. The analytical solutions for longitudinal motion were obtained by combining the motion equations and boundary conditions, and then, the transverse bending of rocket was examined solved by considering a coupled forcing vibration with varying parameters. Numerical solutions for a rocket with end-varying thrust were studied. It is shown that the lateral vibrations and motion attitudes of rocket depend on the frequencies of varying thrust to great extent, and an important phenomenon, beating, maybe take place. The proposed approach is more accurate and efficient in comparison to those standard numerical techniques.
基金the China Post Doctor National Fund (No.AD4122,2008)
文摘The design of the re-entry space vehicles and high-speed aircraft structures requires special attention to the non-linear thermoelastic and aerodynamic instabilities.The thermal effects are important since temperature environment influences significantly the static and dynamic behaviors of flight structures in supersonic/hypersonic regimes.The dynamic behavior of a double-wedge lifting surface with combined freeplay and cubic stiffening structural nonlinearities in both plunging and pitching degrees-of-freedom(DOF) operating in supersonic/hypersonic flight speed regimes has been analyzed.In addition a third order piston theory aerodynamics(PTA) is used to evaluate the non-linear unsteady aerodynamic loads applied to the wing section.Loss of torsional stiffness that may be incurred by lifting surfaces subjected to axial stresses induced by aerodynamic heating is also considered.The aerodynamic heating effect is estimated based on the adiabatic wall temperature due to high speed airstreams.It is demonstrated that serious losses of torsional stiffness may occur in such lifting surfaces;the influence of various parameters such as flight condition,thickness ratio,freeplays and pitching stiffness nonlinearity are discussed.
