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Volume 31 (1993)
- Issue 6 Pages 324-
- Issue 5 Pages 264-
- Issue 4 Pages 192-
- Issue 3 Pages 114-
- Issue 2 Pages 58-
- Issue 1 Pages 3-
Predecessor
Volume 31, Issue 4
Displaying 1-7 of 7 articles from this issue
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Hiroshi MIMURA1993 Volume 31 Issue 4 Pages 192-198
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSA simple model was proposed to combine the weakest link model and Petch model. The present model can explain consistently the empirical rules of fracture toughness as stated in the followings.
(1) Fracture toughness of crack initiaion, KC, or that of crack arrest, Kca, has Arrhenius type temperature dependence with lower shelf on low temperature side.
(2) In Arrhenius plot the gradient and intercept of Kca are larger than those of KC.
(3) Dynamic fracture toughness Kld shows narrower scatter than KIC does. Lower bound of Kld coincides with that of Kla.View full abstractDownload PDF (677K) -
Ryosuke KANAI, Koichi HAGIWARA1993 Volume 31 Issue 4 Pages 199-209
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSSteel liner on inner surface of prestressed concrete (PC) cylindrical vessel may buckle by compressive deformation of the concrete which is caused at the construction stage as the steel liner is fitted on the concrete guard dike with anchors. The inside pressure on such a buckled plate will press it to PC vessel, and may make it into the unbuckled state under some condition.
In this report, the authors present the calculation method of the behavior of the buckled plate under pressure, and the results of numerical calculations for typical patterns.
As the result, the behavior of the buckled plate was clarified including the critical point when the whole plate touches entirely to the vessel in an unstable manner.View full abstractDownload PDF (993K) -
Influence of Clad Metal on Burst Pressure of Clad PipeFumiyoshi MINAMI, Jian HUANG, Masao TOYODA, Joe KONDO, Moriyasu NAGAE, ...1993 Volume 31 Issue 4 Pages 210-219
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSDeformation behavior of clad pipe under uniform internal pressure has been analyzed with emphasis on the influence of clad metal on the burst strength of the clad pipe. The maximum pressure pmax and the critical circumferential strain(εθ)max at pmax can be estimated well by a model based on the rule of mixture. Clad metal contributes to the maximum pressure pmax of the clad pipe as an equivalent base metal of thickness bi⋅(δTC/δTB), where bi is the thickness of the clad metal, and δTB and δTc are the base metal strength and the clad metal strength, respectively. Design concept of the clad pipe has been discussed in the light of this finding. The most popular concept conventionally applied, in which the existence of the clad metal is not taken into account at all, gives too much conservative evaluation of the maximum pressure pmax in the case that the clad metal has apparently higher strength than the base metal. Alternative concept that all clad components are assumed to be constructed of homogeneous base metal results in unsafe estimation of pmax when the strength of the clad metal is lower compared to the base metal strength. ASME method seems to be a combination of the former concept and the following new concept proposed in this paper. The new design concept is a simple one which treats the clad metal as the equivalent base metal of thickness bi⋅(δTC/δTB) and gives more reasonable estimation of the burst strength of the clad pipe.View full abstractDownload PDF (959K) -
Study on the effect of hydrogen gas content on welding speedKeun Ha Sin, Jin Duk Kim1993 Volume 31 Issue 4 Pages 221-226
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSAn experimental test of the welding system shielding gas variation (H2 GAS) on plasma-TIG tandem system, was carried out in a commercial line to make SUS 304 stainless steel welded pipe of 150φ outside diameter, 3mm wall thictness. A shielding gas equipment were set to increase of hydrogen content of 5%, 10%, 15% respectively, in argon atmosphere. A plasma torch was located 20mm before the second squeeze roll and a TIG torch was located 200mm after second squeeze roll. An available speed of the plasma-TIG tandem system could be at least doubled by the change of hydrogen gas volume rate 5%, -15%, and satisfactory weld quality was obtained.View full abstractDownload PDF (3307K) -
Osamu YOKOTA, Hiroshi DOHI1993 Volume 31 Issue 4 Pages 227-235
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSA eddy current method is effectively applied to detect surface opening cracks on metal materials and reinforcing steel bars buried in concrete structures. The measurement of the covering depth and diameter of bars using the instrument was already been reported. To the best of the authors knowledge, amplitude, phase and pattern on Lissajous' patterns obtained from the shapes of bars, adjacent bars and inclined bars have not been reported.
An attempt has therefore been made in this paper to find the correlation between rienforcing bars and Lissajous' patterns using eddy current testing. A probe coil was used, and bars were measured at 8kHz. The results obtained were as follow:
Lissajous' patterns were influenced by the bar materials, diameter and covering depth of the reinforcing bars. In detection of the deformed bars, Lissajous' patterns were shown as a loop. Even when the specimen made of the same material, the pattern in Lissajous' pattern changes depending upon the shape of specimen. In other words, while the pattern from a round bar presents a linear figure, the pattern from a flat bar does a curved figure. The smallest limit of distance between two bars recognizable was almost 80mm. This is nearly equal to coil diameter.View full abstractDownload PDF (800K) -
Osamu YOKOTA, Hiroshi DOHI1993 Volume 31 Issue 4 Pages 236-243
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSA eddy current method is used for the detection of cracks in metal materials and reinforcing steel bars buried in concrete structures. In the experiment, two types of probe coil were used, and the test frequencies of 2, 8, 32, and 128kHz were applied. Lissajous' pattern of signal from mortar, contaminated mortar zone and corroded reinforcing bar in concrete were measured to provide fundamental data for bars. The results obtained were as follows:
The amplitude and phase of Lissajous' pattern of signal obtained from bars barely change with or without concrete. Lissajous' pattern was influenced by the mortar zone, contaminated mortar zone, and reinforcing bars with corroded or not.
The amplitude is increased and the phase is shifted in a clockwise rotation as the test frequency is increased.View full abstractDownload PDF (3288K) -
Akihiko KATOH1993 Volume 31 Issue 4 Pages 244-248
Published: July 25, 1993
Released on J-STAGE: August 05, 2010
JOURNAL FREE ACCESSThis paper introduces the acitivity of standardization of high pressure cylinders for natural gas vehicles at ISO.
Natural gas vehicles have been recently high lighted as a low emission vehicle and a alternative fuel vehicle in the world. Natural gas vehicles have to mount high pressure cylinders for gas storage tanks. As the total number of natural gas vehicles has incresed, international standard for these cylinders for natural gas vehicles has been requested.
On the basis of these request, ISO started working group activity to make a draft of standard for these cylinders. Thirteen countries including Japan have taken a part in this working group. Last winter, draft of the standard has offered to a parent committee.
This draft involves new technologies such as filament wound cylinders with not only metal liner but plastic liner and new design philosophy such as fracture mechanics. These new philosophies are still controversial at working group because of shortage of both results of actual use and background technical data. Anyhow, it is expected that more significant discussion for standardization of cylinders for natural gas vehicles will be made based on offered draft.View full abstractDownload PDF (1618K)
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