| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 98 === Due to the fact that Taiwan is confronted with seasonal monsoon in winter and typhoons in summer with strong wind gusted up to 60 m/s. The damage costs caused by these natural hazards are inevitably high and are observed to be more severe during past years owing to certain climate factors such as the global warming. Due to global warming, the intensity of typhoons tends to be stronger and thus seriously threatens the safety of whole pole. The study using numerical simulation and stress wave technology to assess the integrity of the poles.
In this study, the non-destructive testing method using a steel ball as an impactor were performed on the stored and in-used poles to obtain the amplitude spectra of the test signals. These spectra were also compared to the ones obtained from the finite element models constructed by ANSYS. No matter the pole is damaged or not, the spectrum shows multiple peaks with constant frequency interval. For the undamaged poles, the amplitude of the peaks tends to monotonically increase and then decrease with the gain of frequency in the region composed by high-amplitude peaks. The peaks tends to oscillate in amplitude around 2500 Hz for the poles with one surface crack with depth larger than 3.5 cm. The phenomenon becomes more obvious when the crack went deeper. In addition, the average frequency interval of the peaks can be obtained by dividing the frequency interval of multiple peaks by the number of troughs. and then the average velocity of stress wave traveling in the pole can be obtained. When the average velocity lower than 4600 m/s, the pole may contain deep cracks or pole length is deviated from the design.
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