Study On Finite Element Power Flow Calculation And Transfer Characteristics Of Fully Flexible Isolation System

With the continuous progress of production and life,mechanical equipment presents the development trend of high speed,complexity and lightness.Vibration in nature is the transfer of energy in the structure.In order to achieve effective isolation and noise reduction it is necessary to clarify the transfer path of vibration energy in the structure.With the support of the national natural science foundation of "Broadband acoustic vibration prediction hybrid energy flow method of high iron and super large structure"(5 1 675306),the flexible irregular plate modelledthe machine and the spatial elastic beam was used to simulate isolator,so that establishing a fully flexible isolation system which is taken more factors into consideration.Then the finite element method was applied to calculate the vibration pover flow for the evaluation of isolation effect,which was extending the application of the power flow method.Firstly,the finite element method is applied to discrete each part of the structure Through meshing the machine,vibration isolator and foundation with quadrilateral element,triangular element and 12-node spatial beam element respectively,processing them at the coupling points,and assembling the overall stiffness matrix,the finite element model of the fully flexible system of irregular structure is established.Through calculation,the generalized force and generalized displacement at the excitation position of the machine,the coupling point between the isolator and the foundation,and the coupling point between the isolator and the machine are obtained.Then,the power flow transmitted to the equipment and the receiving structure is deduced through the structural sound intensity calculation formula.Then the vibration transfer characteristics of the fully flexible isolation system are evaluatedSecondly,according to the above dynamic model,the finite element power flow method was used to calculate the force information and displacement information at each node of the structure,so that the vibration energy of this node can be calculated as well.The vibration energy distribution and power flow transfer on the structure can be visualized through energy density,energy gradient and energy flow diagram.This method can predict the danger area of structural vibration,improve the limitation of the traditional admittance po wer flow method which can only calculate the power flow at the coupling point,and provide guidance for vibration path identification and optimal design of isolators.Thirdly,the most important isolation element is analyzed.Traditional isolators are mostly vertical discrete models,which makes a big error in the prediction of high frequency vibration because the mass and bending stiffness of the isolator are not considered.In this paper,by means of the finite element pouer flow method,the influence of various parameters,different forms and arrangement of isolators(such as the arrangement Angle of oblique isolator and the radian of arc isolator.)and continuous isolator model on the power flowtransmission by the system was discussed.And some useful results were obtainedFinally,the average power flow in frequency domain is defined,the influence of parameter changes on the average power flow is analyzed.And the main parameters in the isolation system are determined.Then the optimization design of the isolation system is carried out,which was of signi ficance for the practical applicationof the fully flexible isolation system in engineering.