Date of Award

2021

Document Type

Dissertation

Degree Name

Ph.D.

Department

Mechanical Engineering

First Advisor

Maciej Kumosa

Second Advisor

Joseph Hoffman

Third Advisor

Peter Laz

Fourth Advisor

Yun-Bo Yi

Fifth Advisor

Paul Predecki

Sixth Advisor

Michael Daniels

Keywords

Mechanical engineering, Conductors, Fiber Bragg Grating (FBG)

Abstract

This combined experimental and numerical study addresses mechanical effects associated with static and dynamic loading of novel High Temperature Low Sag (HTLS) transmission line polymer core composite conductors. The developed methodology was successfully applied to ACCC® to explain the complex failure mechanisms associated with combined bending and tension loading. Furthermore, the use of Fiber Bragg Grating (FBG) sensors was investigated for the first time to monitor the ACCC® design during installation and in-service.

Transverse low-velocity impacts to the ACCC® conductor having either free or constrained end conditions and large axial tensile loads were performed. It was identified that the most damaging condition under impact is when the conductor had free ends and was thus subjected to severe bending. The experimental work performed using an original approach was supported by non-linear static and dynamic finite element analyses.

For the multiaxial case of rods subjected to bending and axial tension, the axial stresses were predicted analytically and numerically with the likely failure initiating locations identified based on the theoretical composite compressive strengths. The initiating damage mechanisms change from compressive to tensile modes as axial tension increases. It has been shown for the first time that the natural presence of fiber misalignment must be considered in the failure analysis of hybrid composite rods as it can significantly reduce bending strength and influence the location of damage initiation.

It has been demonstrated that FBG sensing is a viable technique for in-service monitoring of ACCC® conductors subjected to a variety of static and impact situations. Under static and low energy/velocity conditions, surface mounted sensors can accurately measure strains both on the bare rods and inside the conductors. The tests on the fullscale conductors under low energy impact also showed that the sensors can identify the location and magnitude of impact with a high degree of sensitivity. These results, combined with the intrinsic properties of optical sensors and fibers, indicate the FBG sensors could be especially useful in the monitoring of low and high energy impact events in-service. Finally, an evaluation of using of embedded FBG sensors inside the hybrid composite core of ACCC® is presented.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Provenance

Received from ProQuest

Rights holder

Daniel H. Waters

File size

124 pgs

File format

application/pdf

Language

en

Discipline

Mechanical engineering

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