Modeling And Characteristics Research Of The CFRP Driveline System

As Carbon Fiber Reinforced Plastic(CFRP)has the advantages of high specific strength,high specific modulus,large damping ratio and fatigue resistance,drive shaft made of CFRP is especially suitable for transmission systems with long span,large torque and high rotation speed.The United States,Germany,Norway and other countries have applied CFRP driveline system to cooling towers,helicopters,naval ships and other equipment,and achieved good effect.The vibration performance of the CFRP driveline system directly affects that of the entire mechanical equipment.However,the current researches on the dynamics of CFRP driveline system only stays at the level of CFRP shaft tube,and those on the system dynamics of driveline are still in blank.Therefore,studies centering on dynamics modeling,dynamic characteristic analysis and vibration tests of CFRP driveline system are of great significance for its engineering popularization and application.The main research contents of the paper are as follows:Study on the stiffness model of the CFRP shaft tube.The stress-strain of the composite shaft tube was analyzed under the three-dimensional stress state,and the continuous cross layer discrete theory was built by combining the molding process characteristics of composite shaft tube.On this basis,method of mechanical analysis was used to build unified three-dimensional stiffness analytical models for thin/thickwall composite shaft tube.Through the bending and torsional tests of the CFRP shaft tube specimens,and a comparison with the classical lamination theory,finite element method,and classical analytical method,the accuracy of the three-dimensional stiffness analytical model was verified.Study on the damping model and characteristic of the CFRP shaft tube.Combined with the composite damping loss factor model and the finite element method,the improved damping numerical model of CFRP shaft tube based on inverse deflection transformation was proposed.The damping of CFRP laminate was tested and analyzed and the damping loss factor parameters of CRFP material used in the paper were reversed.On this basis,the accuracy of the improved damping numerical model was verified through the CFRP shaft tube bending and torsional damping tests.Then,the bending damping and torsional damping characteristics of CFRP shaft tube were studied,and the effect law of lamination parameters and vibration order changes on CFRP shaft tube damping was obtained.Study on the vibration theoretical model and dynamic characteristic analysis of the CFRP driveline system.Based on the studies of the stiffness and damping characteristic of CFRP shaft tube,the bending vibration and torsional vibration of the CFRP driveline system were studied,and the vibration theoretical model of CFRP driveline system was built.The bending vibration and torsional vibration characteristics of the CFRP driveline system used on heavy machine tool and ship were analyzed respectively to obtain the effect law of changed CFRP shaft tube parameters on the natural frequency and unbalance response of the driveline system.Compared with the dynamic characteristics of the metal driveline,the vibration stability of the CFRP driveline was evaluated and analyzed,and the design interval of the CFRP shaft tube lamination parameters while the bending vibration and torsional vibration of the CFRP driveline meet the stability requirements was defined.Vibration test study of the CFRP driveline system.The bending vibration and torsional vibration of the test pieces of CFRP driveline used on heavy machine tool and ship were tested respectively.By comparing with the vibration theoretical model of CFRP driveline system proposed in this paper,the accuracy of the theoretical model was verified.Some conclusions drawn from the vibration stability analysis of the CFRP driveline were verified by experiments.In this paper,the dynamic theoretical model and vibration test of the CFRP driveline are studied at the system level,which makes up for the insufficiency of researches on CFRP driveline system dynamics,and lays a theoretical foundation for the engineering application of CFRP driveline.