Flexible Compensation Design And Mechanical Performance Analysis Of Composite Transmission Shaft

Composite transmission shaft has the high specific stiffness,high specific strength,excellent fatigue resistance and designability characteristics,which has been widely used in the transmission devices of helicopters,automobiles and ships.Metal transmission shaft mainly uses coupling or diaphragm to solve the misalignment problem of transmission shaft.For composite transmission shaft,owing to its designability and integrated forming advantages,it is a good choice to introduce composite diaphragm to realize the flexible compensation of misalignment problems.The composite drive shaft with diaphragm can realize the angular alignment of the structure besides torque transmission.The composite drive shaft with diaphragm has the advantages of designability and integrated forming,which has the great application potential in the engineering.However,the composite drive shaft with diaphragm not only requires to maintain high torque transmission ability,but also needs to have strong flexible compensation ability,which will have a challenge for the overall structure design.This study focuses on the composite drive shaft with diaphragm,carries out the size optimization design analysis for its compensation performances and keeping transmission torsion ability under complex load,and analyzes the failure process of composite drive shaft with diaphragm,which can lay a theoretical foundation for the integrated design of flexible compensation of composite drive shaft.Firstly,in order to realize the flexible compensation of the composite transmission shaft,the typical diaphragm structure and drive shaft parameters are selected to establish the finite element model of the composite drive shaft with a diaphragm.and experimental tests are used.Combined with experimental and numerical analysis methods,a preliminary stiffness analysis of the model is studied.Compared with the angular compensation experiments of the drive shaft,the validation of the numerical model is verified,which can provide a model basis for the subsequent parameter optimization and failure analysis.Secondly,a parametric model of the composite material transmission with diaphragm is established.A sequential quadratic programming optimization algorithm with the twisting and bending of the transmission shaft stiffness as objectives,considering the limitation of the shaping process and material strength of the drive shaft,is used to optimize the transmission shaft size parameters and composite layup.The relationship between the parameters and the bending stiffness and torsion stiffness of the overall structure is quantitatively obtained by using the optimized batch parameter calculation method,which can determine the optimal size parameters of the composite transmission shaft.Finally,considering the factors of the transmission shaft compensation angle and the composite layer angle,different strength criteria are used to analyze the failure of the transmission shaft under the compensation state.Furthermore,the three-dimensional Hashin criterion is used to study the progressive damage analysis of the transmission shaft.The effect of composite material layup and the size of the diaphragm on the failure process of the composite shaft with the diaphragm is obtained,which can reveal the main failure mechanisms of the transmission shaft under the flexible compensation state.