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Characteristics analysis of hydraulically damped rubber mount (HDM) for vibration isolation in automotive powertrain is very important at the design and development stage of HDM. Fluid-structure interaction (FSI) between rubber parts and fluid flow in chambers in HDM is critical to the frequency-and amplitude-dependent characteristics of HDM. In this paper, an arbitrary-Lagrangian-Eulerian (ALE) based coupling finite element (FE) method is developed to solve fully coupling problem of FSI in HDM. A typical kind of HDM in a vehicle powertrain mounting system composed of rubber spring, two fluid chambers, fluid track and decoupler is selected to investigate performance prediction of HDM. Dynamic characteristic analysis under typical working condition are calculated and compared with experiment results. The agreeable comparison results verify the effectiveness of the presented FSI formulation and characteristic prediction approach of HDM.

To predict dynamic characteristics of hydraulically damped rubber mount (HDM), some key parameters in lumped-parameter model of HDM, such as volumetric elastic characteristics of fluid chambers and equivalent piston cross-section area of upper chamber, must be determined in some special ways because of difficulty in experimental measurement. In this paper, a kind of simulation approach of volumetric elasticity is developed by using finite element (FE) code of ABAQUS on the basis of hydrostatic fluid-rubber interaction modeling method. Contributions of different rubber parts to volumetric elastic characteristics are revealed. Predications of dynamic characteristics and frequency response analysis of a typical HDM with fixed-decoupler verify the effectiveness of the proposed parameter identification method.

In this study, the genetic algorithm so called GA is newly applied for the optimization of many engine mounting parameters, calculations of stiffness matrix and inverse matrix to obtain 6 degrees of freedoms displacements at mounting points and a center of gravity. As a result, the optimized result could be shortly obtained in a minute, and an inexperienced engineer could easily make the optimum engine mounting layout, which can satisfy the vibration isolation and the non-interference in an engine compartment.

This paper presents the polytopic modeling method and state variable observer design approach for semi-active suspension with changeable damping and variant stiffness elements. And such semi-active suspension system is suitable to be modeled as a dynamic polytopic system where the extreme vertices of damping and stiffness values are taken as the convex vertices of polytope. Thus, a dynamic polytopic model is the convex synthesis with all the vertex system dynamics and linear system theory can be applied to the system at each vertex. Herein, the conventional Kalman filter theory is utilized to design the observer for each vertex system, then the polytopic observer is formulated by a convex synthesis. The proposed observer design approach is testified by numerical study and vehicle test.

As an important class of nonlinear system, polytopic bilinear system is investigated. Combined with the properties of convex polytope, the nonlinear control for polytopic bilinear system is formulated by synthesizing nonlinear H∞ controller which is designed for polytopic bilinear system at vertices. For a semi-active suspension system with controllable damping and variant stiffness elements, it is easily modeled as a polytopic bilinear system model. In this case, the desired nonlinear control properties are pursued in making effective use of the changeable damping property while the variant stiffness is taken as the affine parameter of polytopic model. Therefore, polytopic bilinear system model could be reduced to a feasible problem by polytopic convex decomposition. Then the control problem of bilinear system model is to find a solution of nonlinear H∞ control.

Since interior noise has a strong effect on vehicle salability, it is particularly important to be able to estimate noise levels accurately by means of simulation at the design stage. The use of sensitivity analysis makes it easy to determine how the analytical model should be modified or the structure optimized for the purpose of reducting vibration and noise of the structural-acoustic systems. The present work focused on a structural-acoustic coupling problem. As the coefficient matrices of a coupled structural-acoustic system are not symmetrical, the conventional orthogonality conditions obtained in structural dynamics generally do not hold true for the coupled system. To overcome this problem, the orthogonality and normalization conditions of a coupled system were derived by us. In this paper, our sensitivity analysis methods are applied to an interior noise problem of a cabin model.