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• Conferences, Lectures, & Seminars (35)
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Events for July 19, 2007

• Jul

  19

  Discover Engineering

  Thu, Jul 19, 2007 @ 09:00 AM - 04:00 PM

  Viterbi School of Engineering Student Affairs

  Conferences, Lectures, & Seminars

  
  

  An intensive introduction to the various Engineering disciplines for high school students.

  Audiences: High School Students

  Contact: Larry Lim

  

• Jul

  19

  Degenerated shell of finite element for smart structures

  Thu, Jul 19, 2007 @ 03:00 PM - 04:00 PM

  Sonny Astani Department of Civil and Environmental Engineering

  Conferences, Lectures, & Seminars

  
  

  Speaker:Dr. S. Narayanan
  Indian Institute of Technology Madras
  Department of Mechanical EngineeringDegenerated Shell Finite Element for Smart Structures Abstract
  This paper deals with the formulation of a nine noded piezolaminated degenerated shell finite element for modeling and analysis of multi-layer composite general shell structures with bonded/embedded distributed piezoelectric sensors and actuators. The main advantage of degenerate shell element is that it not based on any shell theories and is applicable over a wide range of curvatures and thicknesses. This element is developed by using degenerate solid approach based on Reissner-Mindlin assumptions which allow the shear deformation and rotary effect to be considered and 3D field is reduced to a 2D field in terms of mid surface nodal variable. Uniformly reduced integration is carried out to overcome membrane locking and shear locking (Prathap, 1993) and the numerical integration is carried out in all three directions to obtain accurate results. The distributed PZT sensors and actuators used in the composite smart structures are relatively thin and could be with arbitrary variation of curvatures and thicknesses. They cannot be modeled with the shell elements proposed based on curvilinear shell theories as they would need specification of constant shell curvatures. Modeling them with piezo finite elements available in popular commercial codes like ABAQUS, ANSYS, MSC.MARC, etc. would be computationally inefficient and in view of these, the present proposed degenerated shell element would of use giving good computational accuracy and efficiency. The present element has 45 elastic degrees of freedom and ten electric degrees of freedom. per piezoelectric layer in the element. The potential induced due to bending deformation is more accurately represented by assuming quadratic variation of electric potential through the thickness of each piezoelectric layer. This is achieved by interpolating using nodal mid-plane electric potentials and one electric degree of freedom representing the potential difference between the top and bottom surfaces of the piezoelectric layer. Then few case studies of composite general shells with piezoelectric sensors and actuators have been considered by modeling them with the above elements and the active vibration control performance has been studied.

  Location: Kaprielian Hall (KAP) - rielian Hall, 203

  Audiences: Everyone Is Invited

  Contact: Evangeline Reyes