Semester

Spring

Date of Graduation

2004

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

Roger H. L. Chen.

Abstract

The main objective of this study is to simulate ultrasonic wave propagation in solid cylindrical rods. In this study, both experimental investigations and theoretical analyses are conducted. In the experiment, the 4.2 mm diameter center wire of the commonly used Grad 250 7-wire strand have been employed as the specimen and all the specimens are under zero tensile force. There are 3 rods (center wire) of different lengths used in this study. The DS345 arbitrary function generator, PICO sensors, and S9208 displacement transducer is used for measuring the results of the ultrasonic wave propagations. In the FEM analyses, each specimen with the same input is generated for comparing with the experimental results. In addition, the input frequency, element size, and integration time step are discussed to evaluate the accuracy of the FEM results. The output waveform, wave velocity, and frequency components are compared between experimental and FEM results. A time-frequency domain tool, Wigner-Ville Transform (WVT), is also employed to provide better information regarding frequency dispersion and the concentration of energy under a certain frequency input. The comparisons show that results correlate well, and good measurement accuracy is observed, indicating that FEM can also be an efficient method to simulate the ultrasonic wave propagation in an elastic cylindrical rod. This technique can be used to develop the data base for certain pre-stressing tendons used in concrete structures in order to determine the residual force or even defects in the strand in the future.

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