Circumferential waves in thin-walled cylindrical shells = 얇은 원통형 튜브에서의 Circumferential waves

Three types of multiple echo returns confirming the existence of circumferential waves traveling within shells were observed from the backscattering of short ultrasonic pulses(1 μsec for main peak) by air-filled or water-filled nuclear fuel cladding tubes in water. The contribution of the circumferential waves in the backscattering patterns was found to be more significant at high frequencies(2.25 and 5Mc) than at low frequency(1Mc). By the simplified geometrical approach of Fekih and Quentin, the values for velocity and attenuation of the circumferential waves traveling along the effective mean circle with radius $r_{eff}$=(outer radius a + inner radius b)/2 were obtained. The measured velocities and attenuations were plotted as a function of the product of frequency f and shell thickness d (the region studied is $0.22\times10^6mm/sec0.7. The increasing rate of attenuation of the first transverse mode, however, was larger than that of the Rayleigh mode. Contrary to the $S_o$ Lamb plate mode, the first transverse mode had cut-off frequency, which was given by $f \cdot d = (1-b/a) C_T/2cos^{-1}(b/a)$. The cut-off frequency thus increased as the curvature of a shell increased.
Advisors
Suh, Kyung-Soo서경수
Publisher
한국과학기술원
Issue Date
1985
Identifier
64470/325007 / 000831651
Language
eng
Description

학위논문(석사) - 한국과학기술원 : 물리학과, 1985.2, [ v, 98 p. ]

URI
http://hdl.handle.net/10203/48110
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=64470&flag=t
Appears in Collection
PH-Theses_Master(석사논문)
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