The paper presents an analytical study of the helicopter rotor vibratory loadreduction design optimization with aeroelastic stability constraints. The composite rotor blade ismodeled by beam type finite elements, and ...The paper presents an analytical study of the helicopter rotor vibratory loadreduction design optimization with aeroelastic stability constraints. The composite rotor blade ismodeled by beam type finite elements, and warping deformation is taken into consideration for2-dimension analysis, while the one-dimension nonlinear differential equations of blade motion areformulated via Hamilton's principle. The rotor hub vibratory loads is chosen as the objectivefunction, while rotor blade section construction parameter, composite material ply structure andblade tip swept angle as the design variables, and au-torotation inertia, natural frequency andaeroelastic stability as the constraints. A 3-bladed rotor is designed, as an example, based on thevibratory hub load reduction optimization process with swept tip angle and composite material. Thecalculating results show a 24. 9 percent-33 percent reduction of 3/rev hub loads in comparison withthe base-line rotor.展开更多
A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectiona...A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectional vibration reduction for a tuned rolling mass damper with a single concave structure.First,the Bi-TRMD device is introduced,and its three-dimensional(3D)mechanical model is established.The motion equations of the model are de-rived using the Gibbs-Appell equation,and a trajectory pre-diction method for the sphere and structure within the model is developed.This method demonstrates that the rolling motion of the sphere around orthogonal axes is nearly indepen-dent within a limited range,enabling the simplification of the 3D model into a two-dimensional(2D)model.The accuracy of this simplification is validated through case analysis.The vibration reduction parameters are optimized using the 2D model and Den Hartog theory,leading to the derivation of mathematical expressions for the optimal frequency ratio and damping ratio.Subsequently,the bidirectional vi-bration reduction performance of the Bi-TRMD is analyzed.The results show that under white noise excitation,the Bi-TRMD achieves a bidirectional peak acceleration reduction rate that is 9.92%and 7.79%higher than that of translational tuned mass dampers(TMD)with the same mass.These findings demonstrate that the proposed Bi-TRMD ef-fectively achieves two-directional vibration reduction with a single concave structure,offering superior vibration reduction performance.展开更多
文摘The paper presents an analytical study of the helicopter rotor vibratory loadreduction design optimization with aeroelastic stability constraints. The composite rotor blade ismodeled by beam type finite elements, and warping deformation is taken into consideration for2-dimension analysis, while the one-dimension nonlinear differential equations of blade motion areformulated via Hamilton's principle. The rotor hub vibratory loads is chosen as the objectivefunction, while rotor blade section construction parameter, composite material ply structure andblade tip swept angle as the design variables, and au-torotation inertia, natural frequency andaeroelastic stability as the constraints. A 3-bladed rotor is designed, as an example, based on thevibratory hub load reduction optimization process with swept tip angle and composite material. Thecalculating results show a 24. 9 percent-33 percent reduction of 3/rev hub loads in comparison withthe base-line rotor.
基金The National Key Research and Development Pro-gram of China(No.2022YFC3801201)the National Natural Science Foundation of China(No.51921006,52478505)+1 种基金the Natural Science Foundation of Guangdong Province(No.2022A1515010403)Shenzhen Collaborative Innovation Project(No.CJGJZD20220517142401002).
文摘A novel bidirectional tuned rolling mass damper(Bi-TRMD)device is proposed,and its dynamic character-istics and vibration reduction performance are investigated.The device achieves the performance goal of bidirectional vibration reduction for a tuned rolling mass damper with a single concave structure.First,the Bi-TRMD device is introduced,and its three-dimensional(3D)mechanical model is established.The motion equations of the model are de-rived using the Gibbs-Appell equation,and a trajectory pre-diction method for the sphere and structure within the model is developed.This method demonstrates that the rolling motion of the sphere around orthogonal axes is nearly indepen-dent within a limited range,enabling the simplification of the 3D model into a two-dimensional(2D)model.The accuracy of this simplification is validated through case analysis.The vibration reduction parameters are optimized using the 2D model and Den Hartog theory,leading to the derivation of mathematical expressions for the optimal frequency ratio and damping ratio.Subsequently,the bidirectional vi-bration reduction performance of the Bi-TRMD is analyzed.The results show that under white noise excitation,the Bi-TRMD achieves a bidirectional peak acceleration reduction rate that is 9.92%and 7.79%higher than that of translational tuned mass dampers(TMD)with the same mass.These findings demonstrate that the proposed Bi-TRMD ef-fectively achieves two-directional vibration reduction with a single concave structure,offering superior vibration reduction performance.
