Fatigue Performance of Brass Light Pole Couplings

Rudd, Joseph T.

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https://hdl.handle.net/2142/18288 Copy

Description

Title

Fatigue Performance of Brass Light Pole Couplings

Author(s)

Rudd, Joseph T.

Issue Date

2011-01-14T22:44:56Z

Director of Research (if dissertation) or Advisor (if thesis)

• Struble, Leslie J.
• Banas, Grzegorz

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Brass
• Fatigue
• CDA360
• Light Pole
• Notch
• Stress Concentration
• Finite Element Analysis (FEA)
• Finite Element Modeling (FEM)

Abstract

Bending tests were performed on behalf of the Illinois Department of Transportation on Copper Development Association 360 brass notched specimens of with internal threading and an external notch cut to a depth of 0.150 in the first design in square, diamond, and individual loading configurations. The stress concentration factor, Ktb, determined by strain measurement at hexagonal and notched sections was 5.70, which is slightly higher than the theoretical stress concentration factor of 4.7. Fatigue tests were also performed on the notched specimens of the first design in full compression-tension reversal using force control. An elastic tension-compression test was performed in order to determine both tensile and compressive stress concentration factors. In tension, Ktt=7.26, while in compression Ktc=6.80. Bending testing was performed for a second design, in which the depth of the notch was increased to 0.155 in, the external notch radius decreased to 1/16 in, and the bevel removed of CDA 360 brass notched specimens using only a single coupling. The stress concentration factor, Ktb, was determined to be 9.0 by use of an extensometer across the notch and a strain gauge on the nominal section. Fatigue tests were also performed on CDA 360 brass notched specimens of the second design in full compression-tension reversal using force control. An elastic tension-compression test was performed in order to determine both tensile and compressive stress concentration factors. In tension, Ktt = 10.80, and in compression Ktc = 10.40. Fatigue testing was performed in the long life regime (104-107 cycles) on both coupling geometries. Due to eccentricities in both the coupling and testing set-up, high bending stresses were recorded during testing, likely contributing to the high variability in fatigue life measurements. Finite element modeling of a two-dimensional cross-section of the coupling was performed using ABAQUS®. A reduced cross-section was used to successfully run the model and good agreement between modeling and experimental data was achieved for the complex geometry.

Graduation Semester

2010-12

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http://hdl.handle.net/2142/18288

Copyright and License Information

COpyright 2010 Joseph T. Rudd

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