The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform

Ml Munjal - One of the best experts on this subject based on the ideXlab platform.

  • 3 d acoustic analysis of elliptical chamber mufflers having an end inlet and a side outlet an impedance matrix approach
    Wave Motion, 2012
    Co-Authors: A Mimani, Ml Munjal
    Abstract:

    The acoustical behavior of an elliptical chamber muffler having an end-inlet and side-outlet port is analyzed semi-analytically. A uniform Piston source is assumed to model the 3-D acoustic field in the elliptical chamber cavity. Towards this end, we consider the modal expansion of acoustic pressure field in the elliptical cavity in terms of angular and radial Mathieu functions, subjected to rigid wall condition, whereupon under the assumption of a point source, Green's function is obtained. On integrating this function over Piston Area of the side or end port and dividing it by Piston Area, one obtains the acoustic field, whence one can find the impedance matrix parameters characterizing the 2-port system. The acoustic performance of these configurations is evaluated in terms of transmission loss (TL). The analytical results thus obtained are compared with 3-D HA carried on a commercial software for certain muffler configurations. These show excellent agreement, thereby validating the 3-D semi-analytical Piston driven model. The influence of the chamber length as well as the angular and axial location of the end and side ports on TL performance is also discussed, thus providing useful guidelines to the muffler designer. (c) 2011 Elsevier B.V. All rights reserved.

  • Three-dimensional acoustic analysis of an elliptical chamber muffler with a side inlet and a side outlet
    2011
    Co-Authors: A Mimani, Ml Munjal
    Abstract:

    The acoustical behaviour of an elliptical chamber muffler having a side inlet and side outlet port is analyzed in this paper, wherein a uniform velocity Piston source is assumed to model the 3-D acoustic field in the elliptical chamber cavity. Towards this end, we consider the modal expansion of the acoustic pressure field in the elliptical cavity in terms of the angular and radial Mathieu func-tions, subjected to the rigid wall condition. Then, the Green's function due to the point source lo-cated on the side (curved) surface of the elliptical chamber is obtained. On integrating this function over the elliptical Piston Area on the curved surface of the elliptical chamber and subsequent divi-sion by the Area of the elliptic Piston, one obtains the acoustic pressure field due to the Piston driven source which is equivalent to considering plane wave propagation in the side ports. Thus, one can obtain the acoustic pressure response functions, i.e., the impedance matrix (Z) parameters due to the sources (ports) located on the side surface, from which one may also obtain a progressive wave rep-resentation in terms of the scattering matrix (S). Finally, the acoustic performance of the muffler is evaluated in terms of the Transmission loss (TL) which is computed in terms of the scattering pa-rameters. The effect of the axial length of the muffler and the angular location of the ports on the TL characteristics is studied in detail. The acoustically long chambers show dominant axial plane wave propagation while the TL spectrum of short chambers indicates the dominance of the trans-versal modes. The 3-D analytical results are compared with the 3-D FEM simulations carried on a commercial software and are shown to be in an excellent agreement, thereby validating the analyti-cal procedure suggested in this work.

  • Transmission loss analysis of rectangular expansion chamber with arbitrary location of inlet/outlet by means of Green's functions
    Journal of Sound and Vibration, 2009
    Co-Authors: B Venkatesham, Mayank Tiwari, Ml Munjal
    Abstract:

    Transmission loss of a rectangular expansion chamber, the inlet and outlet of which are situated at arbitrary locations of the chamber, i.e., the side wall or the face of the chamber, are analyzed here based on the Green's function of a rectangular cavity with homogeneous boundary conditions. The rectangular chamber Green's function is expressed in terms of a finite number of rigid rectangular cavity mode shapes. The inlet and outlet ports are modeled as uniform velocity Pistons. If the size of the Piston is small compared to wavelength, then the plane wave excitation is a valid assumption. The velocity potential inside the chamber is expressed by superimposing the velocity potentials of two different configurations. The first configuration is a Piston source at the inlet port and a rigid termination at the outlet, and the second one is a Piston at the outlet with a rigid termination at the inlet. Pressure inside the chamber is derived from velocity potentials using linear momentum equation. The average pressure acting on the Pistons at the inlet and outlet locations is estimated by integrating the acoustic pressure over the Piston Area in the two constituent configurations. The transfer matrix is derived from the average pressure values and thence the transmission loss is calculated. The results are verified against those in the literature where use has been made of modal expansions and also numerical models (FEM fluid). The transfer matrix formulation for yielding wall rectangular chambers has been derived incorporating the structural–acoustic coupling. Parametric studies are conducted for different inlet and outlet configurations, and the various phenomena occurring in the TL curves that cannot be explained by the classical plane wave theory, are discussed.

  • transmission loss analysis of rectangular expansion chamber with arbitrary location of inlet outlet by means of green s functions
    Journal of Sound and Vibration, 2009
    Co-Authors: B Venkatesham, Mayank Tiwari, Ml Munjal
    Abstract:

    Transmission loss of a rectangular expansion chamber, the inlet and outlet of which are situated at arbitrary locations of the chamber, i.e., the side wall or the face of the chamber, are analyzed here based on the Green's function of a rectangular cavity with homogeneous boundary conditions. The rectangular chamber Green's function is expressed in terms of a finite number of rigid rectangular cavity mode shapes. The inlet and outlet ports are modeled as uniform velocity Pistons. If the size of the Piston is small compared to wavelength, then the plane wave excitation is a valid assumption. The velocity potential inside the chamber is expressed by superimposing the velocity potentials of two different configurations. The first configuration is a Piston source at the inlet port and a rigid termination at the outlet, and the second one is a Piston at the outlet with a rigid termination at the inlet. Pressure inside the chamber is derived from velocity potentials using linear momentum equation. The average pressure acting on the Pistons at the inlet and outlet locations is estimated by integrating the acoustic pressure over the Piston Area in the two constituent configurations. The transfer matrix is derived from the average pressure values and thence the transmission loss is calculated. The results are verified against those in the literature where use has been made of modal expansions and also numerical models (FEM fluid). The transfer matrix formulation for yielding wall rectangular chambers has been derived incorporating the structural–acoustic coupling. Parametric studies are conducted for different inlet and outlet configurations, and the various phenomena occurring in the TL curves that cannot be explained by the classical plane wave theory, are discussed.

Wen-bin Shangguan - One of the best experts on this subject based on the ideXlab platform.

  • Parameter identifications of the hydraulic mount
    International Technology and Innovation Conference 2009 (ITIC 2009), 2009
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, Zuhua Fang
    Abstract:

    A lumped parameter model is proposed for analysis of dynamic behaviour of a Passive Hydraulic Engine Mount (PHEM) with incorporation of inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviour in the range of both low and high frequencies. Most of the model parameters, including volume compliance of the throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by experimental approach. The advantage of the methods proposed in this paper is accurately abstained the parameters in the initial design stage, thus the mount design time is greatly reduced. (5 pages)

  • modeling and parameter identification for a passive hydraulic mount
    International Journal of Automotive Technology, 2007
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, J W Zhang, Sh Q Feng
    Abstract:

    A lumped parameter model is proposed for the analysis of dynamic behaviour of a Passive Hydraulic Engine Mount (PHEM), incorporating inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviour in the range of both low and high frequencies. Most of the model parameters, including volume compliance of the throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by an experimental approach. Numerical predictions are obtained through a finite element method for responses of dynamic stiffness of the rubber spring. The experiments are made for the purpose of PHEM validation. Comparison of numerical results with experimental observations has shown that the present PHEM achieves good performance for vibration isolation.

  • Non-linear modeling and experimental study of a streamlined Passive Hydraulic Mount
    International Technology and Innovation Conference 2006 (ITIC 2006), 2006
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, Jianwu Zhang, Qishan Feng
    Abstract:

    A lumped parameter model is proposed for analysis of dynamic behaviours of a passive hydraulic engine mount (PHEM) with incorporation of inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviours in the range of both low and high frequencies. The most of model parameters including volume compliance of throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by experimental approach. The experiments are made for the purpose of validation of the PHEM. It has been shown by comparison of the numerical results with the experimental observations the present PHEM possesses of fairly good performance for vehicle industries.

  • modelling of a hydraulic engine mount with fluid structure interaction finite element analysis
    Journal of Sound and Vibration, 2004
    Co-Authors: Wen-bin Shangguan
    Abstract:

    Abstract Hydraulic engine mount (HEM) is now widely used as a highly effective vibration isolator in automotive powertrain. A lumped parameter (LP) model is a traditional model for modelling the dynamic characteristics of HEM, in which the system parameters are usually obtained by experiments. In this paper, a fluid–structure interaction (FSI) finite element analysis (FEA) method and a non-linear FEA technology are used to determine the system parameters, and a fully coupled FSI model is developed for modelling the static and lower-frequency performance of an HEM. A FSI FEA technique is used to estimate the parameters of volumetric compliances, equivalent Piston Area, inertia and resistance of the fluid in the inertia track and the decoupler of an HEM. A non-linear FEA method is applied to determine the dynamic stiffness of rubber spring of the HEM. The system parameters predicated by FEA are compared favorably with experimental data and/or analytical solutions. A numerical simulation for an HEM with an inertia track and a free decoupler is performed based on the FSI model and the LP model along with the estimated system parameters, and again the simulation results are compared with experimental data. The calculated time histories of some variables in the model, such as the pressure in the upper chamber, the displacement of the free decoupler and the volume flow through the inertia track and the decoupler, under different excitations, elucidate the working mechanism of the HEM. The pressure distribution calculated with the FSI model in the chambers of the HEM validates the assumption that the pressure distribution in the upper and lower chamber is uniform in the LP model. The work conducted in the paper demonstrates that the methods for estimating the system parameters in the LP model and the FSI model for modelling HEM are effective, with which the dynamic characteristic analysis and design optimization of an HEM can be performed before its prototype development, and this can ensure its low cost and high quality for development.

  • Modelling of a hydraulic engine mount with fluid–structure interaction finite element analysis
    Journal of Sound and Vibration, 2003
    Co-Authors: Wen-bin Shangguan
    Abstract:

    Abstract Hydraulic engine mount (HEM) is now widely used as a highly effective vibration isolator in automotive powertrain. A lumped parameter (LP) model is a traditional model for modelling the dynamic characteristics of HEM, in which the system parameters are usually obtained by experiments. In this paper, a fluid–structure interaction (FSI) finite element analysis (FEA) method and a non-linear FEA technology are used to determine the system parameters, and a fully coupled FSI model is developed for modelling the static and lower-frequency performance of an HEM. A FSI FEA technique is used to estimate the parameters of volumetric compliances, equivalent Piston Area, inertia and resistance of the fluid in the inertia track and the decoupler of an HEM. A non-linear FEA method is applied to determine the dynamic stiffness of rubber spring of the HEM. The system parameters predicated by FEA are compared favorably with experimental data and/or analytical solutions. A numerical simulation for an HEM with an inertia track and a free decoupler is performed based on the FSI model and the LP model along with the estimated system parameters, and again the simulation results are compared with experimental data. The calculated time histories of some variables in the model, such as the pressure in the upper chamber, the displacement of the free decoupler and the volume flow through the inertia track and the decoupler, under different excitations, elucidate the working mechanism of the HEM. The pressure distribution calculated with the FSI model in the chambers of the HEM validates the assumption that the pressure distribution in the upper and lower chamber is uniform in the LP model. The work conducted in the paper demonstrates that the methods for estimating the system parameters in the LP model and the FSI model for modelling HEM are effective, with which the dynamic characteristic analysis and design optimization of an HEM can be performed before its prototype development, and this can ensure its low cost and high quality for development.

B Venkatesham - One of the best experts on this subject based on the ideXlab platform.

  • Transmission loss analysis of rectangular expansion chamber with arbitrary location of inlet/outlet by means of Green's functions
    Journal of Sound and Vibration, 2009
    Co-Authors: B Venkatesham, Mayank Tiwari, Ml Munjal
    Abstract:

    Transmission loss of a rectangular expansion chamber, the inlet and outlet of which are situated at arbitrary locations of the chamber, i.e., the side wall or the face of the chamber, are analyzed here based on the Green's function of a rectangular cavity with homogeneous boundary conditions. The rectangular chamber Green's function is expressed in terms of a finite number of rigid rectangular cavity mode shapes. The inlet and outlet ports are modeled as uniform velocity Pistons. If the size of the Piston is small compared to wavelength, then the plane wave excitation is a valid assumption. The velocity potential inside the chamber is expressed by superimposing the velocity potentials of two different configurations. The first configuration is a Piston source at the inlet port and a rigid termination at the outlet, and the second one is a Piston at the outlet with a rigid termination at the inlet. Pressure inside the chamber is derived from velocity potentials using linear momentum equation. The average pressure acting on the Pistons at the inlet and outlet locations is estimated by integrating the acoustic pressure over the Piston Area in the two constituent configurations. The transfer matrix is derived from the average pressure values and thence the transmission loss is calculated. The results are verified against those in the literature where use has been made of modal expansions and also numerical models (FEM fluid). The transfer matrix formulation for yielding wall rectangular chambers has been derived incorporating the structural–acoustic coupling. Parametric studies are conducted for different inlet and outlet configurations, and the various phenomena occurring in the TL curves that cannot be explained by the classical plane wave theory, are discussed.

  • transmission loss analysis of rectangular expansion chamber with arbitrary location of inlet outlet by means of green s functions
    Journal of Sound and Vibration, 2009
    Co-Authors: B Venkatesham, Mayank Tiwari, Ml Munjal
    Abstract:

    Transmission loss of a rectangular expansion chamber, the inlet and outlet of which are situated at arbitrary locations of the chamber, i.e., the side wall or the face of the chamber, are analyzed here based on the Green's function of a rectangular cavity with homogeneous boundary conditions. The rectangular chamber Green's function is expressed in terms of a finite number of rigid rectangular cavity mode shapes. The inlet and outlet ports are modeled as uniform velocity Pistons. If the size of the Piston is small compared to wavelength, then the plane wave excitation is a valid assumption. The velocity potential inside the chamber is expressed by superimposing the velocity potentials of two different configurations. The first configuration is a Piston source at the inlet port and a rigid termination at the outlet, and the second one is a Piston at the outlet with a rigid termination at the inlet. Pressure inside the chamber is derived from velocity potentials using linear momentum equation. The average pressure acting on the Pistons at the inlet and outlet locations is estimated by integrating the acoustic pressure over the Piston Area in the two constituent configurations. The transfer matrix is derived from the average pressure values and thence the transmission loss is calculated. The results are verified against those in the literature where use has been made of modal expansions and also numerical models (FEM fluid). The transfer matrix formulation for yielding wall rectangular chambers has been derived incorporating the structural–acoustic coupling. Parametric studies are conducted for different inlet and outlet configurations, and the various phenomena occurring in the TL curves that cannot be explained by the classical plane wave theory, are discussed.

Young Kong Ahn - One of the best experts on this subject based on the ideXlab platform.

  • Performance Analysis of Magneto-Rheological Mounts
    Journal of Intelligent Material Systems and Structures, 1999
    Co-Authors: Mehdi Ahmadian, Young Kong Ahn
    Abstract:

    The effect of various parameters for a magneto-rheological (MR) mount on the vibration isolation performance of the mount is studied. The mount that is used for this study incorporates MR fluid in a conventional fluid mount to open and close an inertia track between the fluid chambers of the mount. It has been shown in previous studies that such switching of the inertia track improves the mount's isolation effect by eliminating the large transmissibility peak that commonly exists at frequencies larger than the notch frequency for conventional fluid mounts. A sensitivity analysis is conducted to evaluate the effect of different parameters, such as the rubber stiffness, inertia track, fluid resistance, Piston Area, and volumetric stiffness on the transmissibility of the mount. The results show that varying the rubber stiffness, Piston Area, and volumetric stiffness of the mount have the greatest effect on the vibration performance of the mount, as measured by its transmissibility.

Yun Xia Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Parameter identifications of the hydraulic mount
    International Technology and Innovation Conference 2009 (ITIC 2009), 2009
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, Zuhua Fang
    Abstract:

    A lumped parameter model is proposed for analysis of dynamic behaviour of a Passive Hydraulic Engine Mount (PHEM) with incorporation of inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviour in the range of both low and high frequencies. Most of the model parameters, including volume compliance of the throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by experimental approach. The advantage of the methods proposed in this paper is accurately abstained the parameters in the initial design stage, thus the mount design time is greatly reduced. (5 pages)

  • modeling and parameter identification for a passive hydraulic mount
    International Journal of Automotive Technology, 2007
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, J W Zhang, Sh Q Feng
    Abstract:

    A lumped parameter model is proposed for the analysis of dynamic behaviour of a Passive Hydraulic Engine Mount (PHEM), incorporating inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviour in the range of both low and high frequencies. Most of the model parameters, including volume compliance of the throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by an experimental approach. Numerical predictions are obtained through a finite element method for responses of dynamic stiffness of the rubber spring. The experiments are made for the purpose of PHEM validation. Comparison of numerical results with experimental observations has shown that the present PHEM achieves good performance for vibration isolation.

  • Non-linear modeling and experimental study of a streamlined Passive Hydraulic Mount
    International Technology and Innovation Conference 2006 (ITIC 2006), 2006
    Co-Authors: Yun Xia Zhang, Wen-bin Shangguan, Jianwu Zhang, Qishan Feng
    Abstract:

    A lumped parameter model is proposed for analysis of dynamic behaviours of a passive hydraulic engine mount (PHEM) with incorporation of inertia track and throttle, which is characterized by effective and efficient vibration isolation behaviours in the range of both low and high frequencies. The most of model parameters including volume compliance of throttle chamber, effective Piston Area, fluid inertia and resistance of inertia track and throttle are identified by experimental approach. The experiments are made for the purpose of validation of the PHEM. It has been shown by comparison of the numerical results with the experimental observations the present PHEM possesses of fairly good performance for vehicle industries.