Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


dissertation_Tan_May 1 2013.pdf (2.97 MB)

ETD Abstract Container

Abstract Header

FREQUENCY AND TIME DOMAIN CHARACTERIZATION OF HYDRAULIC BUSHINGS WITH LONG AND SHORT FLOW PASSAGES

Chai, Tan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1367352796

Abstract Details

2013, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Fluid-filled bushings are commonly used in vehicle suspension and sub-frame systems to improve ride characteristics, control motion, and reduce vibration and noise. Such devices are poorly understood since their stiffness and damping dynamic properties are highly dependent on the excitation frequency and amplitude as well as the static load. Though many hydraulic bushing patents exist, very few scholarly articles have analytically examined their dynamic responses. In order to better understand such devices and to overcome a distinct void in the literature, a controlled laboratory prototype which can provide various configurations is designed, constructed and instrumented; this device accommodates a combination of long and short flow passages and flow restriction elements. First, several common fluid-filled bushing configurations are experimentally examined for their tunable dynamic stiffness and internal pressure spectra (up to 60 Hz). Linear time-invariant models are developed for a bushing with two parallel flow passages using the lumped fluid control volume approach. Salient parameters of frequency domain models are characterized using several analytical and experimental methods. The linear models are validated by comparing predictions with measured stiffness magnitude and loss angle spectra. Second, time domain measurements of transmitted force under step-up and step-down displacement excitations are obtained. Analogous mechanical models for bushings with in parallel or in series passage elements are developed based on the linear system theory, and analytical expressions of transient responses for transmitted force and internal pressure are derived using the convolution method. The system parameters for time domain models are successfully estimated using theory and measurements. The dynamic force measurements are analyzed using the linear system theory, and some nonlinearities are observed in measured time domain data. Next, the nonlinear characteristics of several hydraulic bushing configurations are examined in both frequency and time domains. System parameters and nonlinear fluid resistance properties of the prototype are identified by conducting bench experiments under low and high flow rates. The proposed nonlinear models predict both steady state sinusoidal and transient responses well for both single and multi-passage configurations; significant improvement over linear models is observed. Further, approximate analytical and semi-analytical solutions of the nonlinear model are constructed by using single and multi-term harmonic balance methods. The proposed models provide insights for the dynamic behavior of a fluid-filled bushing system. For instance, the principal features of a practical device are diagnosed using analytical models and measurements for three excitation amplitudes. A design concept that may yield two peaks in stiffness spectra is briefly investigated; some key differences between fluid-filled bushings and hydraulic engine mounts are also analytically examined.
Rajendra Singh (Advisor)
Mechanical Engineering

Recommended Citations

Citations

  • Chai, T. (2013). FREQUENCY AND TIME DOMAIN CHARACTERIZATION OF HYDRAULIC BUSHINGS WITH LONG AND SHORT FLOW PASSAGES [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1367352796

    APA Style (7th edition)

  • Chai, Tan. FREQUENCY AND TIME DOMAIN CHARACTERIZATION OF HYDRAULIC BUSHINGS WITH LONG AND SHORT FLOW PASSAGES. 2013. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1367352796.

    MLA Style (8th edition)

  • Chai, Tan. "FREQUENCY AND TIME DOMAIN CHARACTERIZATION OF HYDRAULIC BUSHINGS WITH LONG AND SHORT FLOW PASSAGES." Doctoral dissertation, Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1367352796

    Chicago Manual of Style (17th edition)

osu1367352796
1,687
© , all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.