Department of Mechanical Engineering

Research - Vibration and Noise Control Laboratory

The research program in the Laboratory combines a balance of measurements, computer simulation, physical modeling, and mathematical analysis, and it is motivated by interesting phenomena that occur in commercial or prototype engineering hardware.

Current and former research projects are briefly described below.  Those projects are directed at understanding fundamental processes through knowledge-based advances, and at offering guidelines for improving performance through technology-based design changes.  The References link provides citations to publications that detail each project’s scope of work, methodology, and results.  Theoretical themes of the research program include:


  • the dynamics of continuous systems such as strings, beams, membranes, plates, and shells, which are described by partial differential equations, and where mass, stiffness, and damping are distributed spatially.
  • gyroscopic effects that arise when small-amplitude vibration is superposed on rigid-body rotation (such as the disks in a hard disk drive, or the rotor in an automobile’s brakes) or on rigid body translation (such as lateral vibration of magnetic tape, or sheet metal webs during their processing).
  • the onset of instability in a dynamic system as caused by external loading, non-conservative mechanisms, or parametric excitation.
  • multi-field coupling between structural vibration and a stress field or a lubricating fluid film.

Research projects are grouped into the following major technologies.  Select a link to jump to project descriptions:

High-Density Computer Data Storage

Computer disk drives and automated robotic tape libraries that store petabytes of data are the “parking lots” of the Information Superhighway.  Vibration phenomena occurring in these mechatronic systems at the micron and nanometer scales can restrict advances in storage density, access time, and data rate.

  

Research projects in this area include:

  • Vibration of flex circuits in hard disk drives and their design optimization
  • Lateral vibration and guiding forces in magnetic tape transport
  • Acoustoelastic vibration coupling among stacked disks on a hard disk drive’s spindle
  • Air entrainment during high speed tape transport and the role of its backcoat morphology
  • Designing disk drive clamping collars to reduce splitting of disk vibration modes
  • Mechanical properties of thin magnetic films using diagnostic micromachined structures

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Design of Automotive Disk Brakes

Modal testing and finite element simulation are used to understand how disk brakes vibrate.  By tuning the natural frequency spectra of rotors, and by incorporating rotor and drum ring dampers, automotive brakes can be designed to produce less squeal noise.

   

Research projects in this area include:

  • In-plane vibration modes of brake rotors, and circumstances in which they couple with bending modes
  • Design of ring dampers for brake rotors and drums that increase damping and passively control vibration and noise
  • Spatial mode shape modulation caused by a rotor’s rotationally periodic cooling vanes and bolts
  • Optimizing the geometry of brake rotors to reduce vibration of certain bending modes

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Manufacture of Sheet Metal, Fiberglass and Polymer Materials

A variety of vibration and applied mechanics issues arise during the production of aluminum and steel sheet stock, polymers, fiberglass, and paper.  Continuous fibers and thin web sheets are flexible mechanical structures that are transported under tension and at high speed during their production and processing.  Research in the Laboratory is directed at improving the dynamic stability, guiding, and positioning of such materials during their manufacture.

 

Research projects in this area include:

  • Buckling of wound rolls of sheet metal due to high stresses, and developing process guidelines to improve quality
  • On-line detection of web wrinkling using non-contact measurement of natural frequencies
  • Optimizing web guiding with self-pressurized air bearings for maximum stiffness and damping of guides
  • Mechanics of chopping fiberglass at high speeds to produce the strands used in certain composite materials

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Machine Dynamics

Belt drives, turbine impellers, and gears transmit power at high speed and can vibrate as a result.  Laser interferometry and sine sweep testing are used in the Laboratory to measure vibration and reduce large amplitude motions of those machine components.

 

Research projects in this area include:

  • Non-linear vibration of power transmission belts and chains
  • Developing non-contact vibration sensors for translating and rotating machine components
  • Vibration generated by the misalignment between V-belts and their sheaves
  • Traveling and standing wave responses in rotationally periodic structures

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