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CivilComp Proceedings
ISSN 17593433 CCP: 84
PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: B.H.V. Topping, G. Montero and R. Montenegro
Paper 182
Working Process Simulation of a Hydraulically Damped Rubber Mount Using Finite Element Analysis with FluidStructure Interaction L.R. Wang^{1}, J.C. Wang^{2}, Z.H. Lü^{3} and I. Hagiwara^{1}
^{1}Department of Mechanical Science and Engineering, Tokyo Institute of Technology, Japan
, "Working Process Simulation of a Hydraulically Damped Rubber Mount Using Finite Element Analysis with FluidStructure Interaction", in B.H.V. Topping, G. Montero, R. Montenegro, (Editors), "Proceedings of the Fifth International Conference on Engineering Computational Technology", CivilComp Press, Stirlingshire, UK, Paper 182, 2006. doi:10.4203/ccp.84.182
Keywords: hydraulically damped rubber mount, engine mount, fluidstructure interaction, finite element, static elastic characteristic, dynamic characteristic.
Summary
Hydraulically damped rubber mounts (HDMs) are widely equipped in vehicle
powertrain mounting systems (PMS) and they play an important role in noise,
vibration and harshness (NVH) control. Understanding the HDM working process is
fundamental to the HDM performance design in order to meet the vibration isolation
requirements of the PMS. Characteristic simulation of HDMs is usually explored using a
lumpedparameter model [1,2], in which fully fluidrubber interactions (FRI) are not
considered. In this paper, the HDM working process simulation is studied based on the use of
finite element (FE) analysis of fluidstructure interaction (FSI).
Firstly, key technologies in the FE analysis of FSI, such as the arbitraryLagrangianEulerian (ALE) mesh control, stable algorithms for fluid FE computation, a numerical method for coupled FE formulation of the FSI and meshing methods for a fluidstructure interface, are introduced [3,4]. Theories of fluid FE formulation in ALE coordinates, the FE method with mixed displacementpressure elements for an incompressible rubber material and constitutive laws for rubber hyperelasticity are presented. A type of HDM composed of a rubber spring, two fluid chambers, a fluid track and a decoupler membrane is selected to investigate the FE modeling technology of the HDM by using the commercial codes ADNIA and ADINAF. An axisymmetric FE model of the HDM with a simplified fluid track into an orifice is developed. The fluid domain is defined by threenode triangular elements (all apex variables and one center velocity) in ALE coordinates; rubber components are defined by fournode mixed displacementpressure elements (one pressure degree of freedom) for the incompressible media in Lagrangian coordinates; and other structures are modeled by fournode displacement elements. To save computation, a compatible mesh is set up along the fluidstructure interface. The constitutive laws of rubber materials in the HDM are identified by adopting a FE method for hyperelasticity in the commercial software ABAQUS [5]. Nodes on the bottom face of lower body are fixed. A vertical loading displacement is given at nodes on the top surface of the upper connector. A direct computing solution is used to calculate the coupled FRI FE formulations. Fluid velocitypressure and structural displacementpressure are obtained simultaneously. Largescale deformation of the fluidrubber interface and element distortion in the fluid field are overcome by a proportional mesh control approach. A kind of quasistatic working process of the HDM is carried out with a slow vertical displacement loading on the top surface of the upper connector. The predicted static elasticity agrees well with the experimental result, which verifies the effectiveness of the modeling approach of the HDM presented. This static working process simulation can be used to evaluate the carrying capacity, to identify chamber volumetric characteristics, such as volumetric elasticity, equivalent piston area used in lumpedparameter models of HDMs [6]. The dynamic working process simulation is performed by adding harmonic vertical displacement on the deformed HDM. Fluid pressurevelocity fields and deformationstress fields of the rubber spring and their dynamic responses under typical working conditions are analyzed, which is helpful to determine volumetric characteristics and to the structural design of the HDM. However, more accurate threedimensional FE models of the HDM should be investigated to predict dynamic characteristics of the HDM, especially the tuned isolator damper effect of the fluid track. The FE based model presented and the simulation approach of the HDM can be applied to other kinds of HDM to predict and reanalyze characteristics in development of the computer aided technology of HDMs. The success of a strongly coupled FE method in solving the fluidlarge deformation rubber interaction of the HDM reveals a promise for the solution of many other engineering FSI problems when using the FE method. References
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