Nonlinear Dynamic Investigation On Piezoelectric Spacecraft Components With Variable Cross-section

In recent years,many new spacecraft components with variable cross-section have been presented with the rapid development of aerospace engineering.Because of the nonlinear geometric factors and on-orbit working environment,the more complicated dynamic behaviors of those spacecraft components will be excited,such as large deformation,cross-section distortion and flexible vibration.For solving those problems,the new structure with piezoelectric material is presented to suppress the vibration of components with variable cross-section.The main purpose of this paper is to establish the new modeling method for solving the dynamic behaviors of variable cross-section spacecraft components under multi-coupling field.Meanwhile,the dynamic behaviors of piezoelectric driving are also analyzed in this paper.Firstly,the influence of variable cross-section geometry on the theoretical neutral layer of spacecraft components have been considered to descript actual position vector relationship between reference points and absolute nodes under the Absolute Nodal Coordinate Method(ANCF).And the new ANCF elements are studied to continuously simulate the variable cross-section spacecraft components.The different mechanics characteristics between element with different cross-section are analyzed to present low order ANCF element.And then,the Pascal polynomials and strain enhance assumption are used to present the complete ANCF elements.It can effectively solve the Poisson locking and section rigidity problems of traditional dynamic models.Secondly,the influences of the asymmetric section shape,material flexibility and structural span on the shear strain are deeply analyzed to propose the aspect ratio criterion and shear performance criterion.And then,the reduction factor that obtained by the aspect ratio criterion and shear performance criterion is proposed to improve the complete ANCF model.Based on complete ANCF method and low order ANCF method,the multi-model hybrid ANCF dynamic modeling method under the same component is established by introducing reduction factor.Furthermore,the thermal internal stress in the stiffness matrix has been transferred to external force matrix by studied the constitutive relation of composite materials and the anti-strain method.It can effectively reduce the nonlinear of the stiffness matrix of hybrid ANCF modeling method.In addition,Chebyshev polynomial theory is also used to optimize the numerical iteration problems in the modeling process,which also can improve the modeling efficiency of hybrid ANCF method.Taking the nonlinear strain field of the components with variable cross-section as input,the strain feedback driving model is established by making the piezoelectric materials as sensor and actuator of components.According to the piezoelectric dynamic behaviors,the dynamic law of piezoelectric suppression on flexible deformation is analyzed.Finally,the model test platform for typical spacecraft structures with variable cross-section was established to verify the feasibility and accuracy of the hybrid ANCF method and the strain feedback driving model.The experimental results show that the dynamic behaviors of the variable cross-section components with large aspect ratio can be accurately calculated by the proposed method.The Poisson locking problem can be also solved in this method.In addition,the vibration and deformation of the curved shell with variable cross-section have been suppressed by the strain feedback driving model,which can optimize the motion process of spacecraft structure.Based on the propose ANCF model and the strain feedback driving model,the mechanical-electric-thermal coupling dynamic responses of the solar-sail mast and the sub-surrounding mirrors with variable cross-section under actual operating conditions.The influence of the piezoelectric ply strategies,large overall motion and piezoelectric gain adjustment coefficient on the structure dynamic are comprehensively analyzed.It can effectively improve the dynamic behaviors of the variable cross-section components during working process.The new dynamic modeling method and dynamic optimization system for flexible spacecraft structure with variable cross-section is studied in this paper.Relay on this method,the dynamic response of multiple factors such as mechanopiezoelectric-environment coupling can be further analyzed.