Study On Vibration Transmission Characteristics Of Double Half Shafts Turntable

It is universally acknowledged that inertial navigation and guidance technology takes thevital place in aviation, spaceflight, navigation field. As the precision of the inertial system andcomponents have been improved, higher requirements of the test equipment need to besatisfied as well. However, test equipment motivated by multiexciter, and then produces anamount of vibration energy. The energy transfers to components under detection viadistinguished paths, which may have a severe impact in the testing process and pose a threatto the improvement of the system performance. Therefore, the study of vibration generatingmechanism and vibration energy transfer distribution in test equipments is of greatsignificance in reducing the vibration noise. This dissertation took the most widely useddouble half shafts type turntable as research object, made the combination of the theoreticalanalysis and numerical simulation, and conducted the transfer characteristics of the vibrationenergy in double half shafts structure. Specific research work is as follows:According to the relation of each substructure connection type and vibration energytransfer path in vibration system, based on structure system description by graph theory inmulti-rigid-body theory, the paper builds complex structural vibration energy transmissionmodeling. The four-pole parameter vector method was adopted to establish a vibration energyanalysis model of chain system when subsystems had equal input and output in the statevector. In case the input and output of subsystems were not equal, four-pole parameter vectormethod was combined with transfer matrix of multi-object system to establish vibrationenergy models of branch-type vibration system and network vibration system. Additionally,the force and velocity formula of connection points was attained through the motioncoordination and force equilibrium relationship between the interfaces of joint subsystems. Sothat it was simple to get corresponding power flow calculation method. In this case, the powerflow was taken as the evaluation index for vibration to analyze energy transfer in everyvibration transmission path and identify the main vibration energy flow path.With respect to vibration analysis methods of complex systems, double half shaftsturntable structure feature and the generating mechanism of vibration, the new approach ofvibration transfer characteristics was put forward on the basis of the mobility power flow. First of all, according to vibration analysis method of complex system, the system wasdivided into4parts: half shaft subsystem, bearing subsystem, frame subsystem and supportbase subsystem. The paper derived transfer matrixes of each subsystem based on four-poleparameter. Then the double half shafts coupling equation was established by transfer matrixmethod of multi-body system. The power flow of subsystem was obtained. The mainvibration source and transfer paths were identified using mobility power flow method undermulti-excitation.According to the feature that double half shafts turntable was made up of plate and solidstructure, taking the finite element dynamic equation into consideration, the calculationformula for power flow in continuum was derived. The method was applied on double halfshafts turntable to identify main transfer path. For multiple nodes transmission vibrationenergy in the connection face of plate and solid, the paper presented a mean square powerflow of evaluation approach. The approach was identified importance of vibration sourceunder multi-excitation. The finite element ABAQUS software was secondary development byscenarios language. The power flow was regarded as field variable. The power flow visibilityof double half shafts turntable was implemented.Several relevant experiments were performed to design and establish double half shaftsexperimental platform. First of all, experiments on the dynamic characteristics of the doublehalf shafts system were conducted to obtain the modal characteristic parameters of thisstructure. The experiment results were in good agreement with the calculations, the analysisof simulation result reflected vibration characteristics of real structure to some extent.Secondly, the test vibration transmissibility of double half shafts turntable was conductedbased on vibration intensity. The experimental results were consistent with the theoreticalanalysis and numerical simulation results to some extent, therefore the theoretical analysis inthis dissertation could be proved feasible.