Title page for ETD etd-0305103-101059


Type of Document Dissertation
Author Piao, Cheng
Author's Email Address chpiao@lsu.edu
URN etd-0305103-101059
Title Wood Laminated Composite Poles
Degree Doctor of Philosophy (Ph.D.)
Department Forestry, Wildlife, and Fisheries
Advisory Committee
Advisor Name Title
Todd F. Shupe Committee Chair
C. F. Niels DeHoop Committee Member
Chung Y. Hse Committee Member
Vijaya Gopu Committee Member
Arnold Bouma Dean's Representative
Keywords
  • variational method
  • energy method
  • finite element
  • analytical
  • theoretical
  • poles
  • composites
  • glue-line
  • glue-layer
  • high-order governing differential equation
Date of Defense 2003-01-23
Availability unrestricted
Abstract
Wood composite poles are new engineered products with polygonal shapes and bonded with synthetic resins. The poles have multiple advantages over the solid wood poles and are a promising solid pole substitute in power transmission, telecommunication, and cable TV services. The use of composite poles may reduce the cost both in materials and manipulation, and facilitate installation and treatment. It is necessary to evaluate the factors that affect their properties and construct theoretical and analytical models to analyze these properties.

Experiments were conducted to investigate strip thickness and number of strips’ (NOS) effects on the flexural properties and shear stress of wood composite poles. Small-scale (diameter = 7.6 cm (3 in), length = 1.16 m (48 in)) and full size poles (diameter = 10.2 cm (4 in), length = 6 m (20 ft) were manufactured for this purpose. Four strip thickness levels and three number-of-strip levels for the small-scale poles, and three thickness levels and two number-of-strip levels for full-size poles were chosen as experimental variables. The lumber was cut into strips, which were bonded with synthetic resin in molds, and the resulting poles were evaluated in a cantilever test. Results show that the effects of strip thickness were negative on glue-line shear and positive on the shear at poles’ clamped ends. But thickness had little effects on maximum bending stress of the small-scale poles and Young’s modulus of both full- and small-scale poles. With the increase of NOS, Young’s modulus of poles was increased. NOS had little effects on the maximum bending stress and glue-line shear of small-scale poles.

A theoretical analysis was carried out to study the deflection and stress of composite poles. Governing differential equations were derived from high-order differential equations based on the principle of minimum potential energy theorem. Transverse shear and body forces were included in the model. Investigations were also carried out to find glue-line effects on the stress and deflection of composite poles. An analytical solution is modeled with the finite element analysis using ANSYS. Both theoretical and analytical solutions were verified by the experimental data.

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