Date of Award

Summer 1990

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Engineering Mechanics

Committee Director

Thomas E. Alberts

Committee Member

Gene Hou

Committee Member

Chuh Mei

Call Number for Print

Special Collections; LD4331.E57C4469

Abstract

It has been demonstrated that constrained viscoelastic layer damping treatments provide an effective means of passive control for structural vibration. These treatments dissipate vibrational energy by inducing shear strain in a thin layer of viscoelastic material. Our interest is in adding passive damping to a structure as an augmentation to active control. For such applications it is desirable to achieve high damping performance in a given frequency range with a minimum of added weight. Most damping treatments employ spatially continuous constraining layers over the entire viscoelastic layer. Plunkett and Lee have shown that the effectiveness of the damping treatment can be significantly increased by sectioning the constraining layer into segments of optimal length for the target frequency range. This thesis uses Plunkett and Lee's method to determine the optimal length of the constraining layer segment, which produces the best damping performance. The analysis begins with basic structures, a simple aluminum flat beam and a thin walled aluminum tube. The basic structures can be considered to represent the arm of a single-link flexible robot experiment. The damping material utilized is 3M ScotchdampTM SJ2015 type 110 viscoelastic polymer (3M ISD-110) and the constraining layer is 10 mil steel (1025) shim. Data is presented to compare experimental results with theoretical and finite element predictions. The finite element model was developed based on MSC/NASTRAN code. The theoretical method generally over predicts the damping ratio in comparison with experimental data, while the finite element method predicts the actual damping and frequency with greater proficiency

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DOI

10.25777/p22z-wm98

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