• Journal of Welding and Joining
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• 제10권4호
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• pp.199-212
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• 1992

Expert system is a practical application part of the artificial intelligence and can be generally described as a computer-based system designed to simulate the knowledge and reasoning of a human expert, and to make that knowledge conveniently available to other people in a useful way. Expert systems consist of three major components, knowledge base, inference engine and user interface. In this paper, it is aimed to construct a prototype system to design the horizontal-typed pressure vessel. To do this, a representative artificial programming language, Turbo Prolog, was employed, and the knowledge representation was mainly done by the production rule such as "If(condition), than (action)" style and by the predicate logic. In the developed system, it was quite easy to represent the knowledge of "If(condition), then (action)"style and by the predicate logic. In the developed system, it was quite easy to represent the knowledge of "If(condition). then(action)" style and the various table-like data. It was also effective to represent the graphics. Though this expert system is by now small and incomplete, it is possible to expand it to a larger and refined system later.rger and refined system later.

• 대한치과보철학회지
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• 제40권2호
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• pp.156-171
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• 2002

The purpose of this study was to measure and compare the strains produced by screw-tightening implant frameworks fabricated by aye different fabrication methods; (1) one-piece cast using plastic sleeve, (2) one-piece cast using gold cylinder, (3) laser welding, (4) soldering, and (5) electrical discharge machining, and also to measure and compare the strains produced when the order of screw tightening was changed A research model incorporating eighteen strain gages was made to measure the fit of implant frameworks in three dimensions. Three implants aligned in an arc were fixed on the top ends of the L-shape aluminum bars of the research model, and standard abutments were joined to the implants with abutment screws. Five types of implant framework were placed on the abutments and screwed by a torque wrench using 10 Ncm. Under the conditions of this study, the following conclusions were drawn: 1. The electrical discharge machining group showed the smallest magnitude of strain, followed by the soldering group, the laser welding group, the one-piece cast group using gold cylinder, and the one-piece cast group using plastic sleeve. However, among the magnitude of strain for the remaining groups except the electrical discharge machining group, there were not significant differences. 2. When the order of screw tightening was changed, there were not significant differences in the magnitude of strain. 3. In comparison with the electrical discharge machining group, the laser welding group and the one-piece cast groups showed greater horizontal distortion and the soldering group showed greater horizontal and vertical distortion.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4317-4328
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• 2023

To ensure the measuring accuracy of the wall temperature, the outer wall temperature measurement values by using three kinds of thermocouple welding methods were analyzed and evaluated in the paper, including single-point flush-mounted in the wall groove method, single-point insert-mounted in the wall groove, and outer surface direct welding method, based on the application of a tube-in-tube condensing heat exchanger. And the impacts of silver, tin, and thermal resistance adhesive as filling materials on wall temperature measurement were also investigated, and the results were compared to that obtained without filling materials. The results showed that the wall temperatures measured by the three welding methods were lower than the theoretically calculated value. And the wall temperature measured by the outer surface direct welding method was lowest under the same experimental conditions. The wall temperatures measured by single-point flush-mounted and insert-mounted in the wall groove methods were also affected by different welding filling materials. It was found that the greater the thermal resistance of filling materials, the smaller the heat loss. By analyzing the reasons for the low measured value of wall temperature, a new wall temperature measurement method was developed to improve the accuracy of the current measurement method. Meanwhile, the outer wall temperature measurement experiments of vertical and horizontal heat transfer tubes were carried out to validate and calibrate the improved outer wall temperature measurement method. The results showed that the average outer wall temperature deviation measured by the improved wall temperature measurement method ranged from - 0.82% to +2.29% for vertical tubes and - 4.75% to - 1.44% for horizontal tubes, and the improved measurement method had good measurement accuracy.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.195-199
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• 2005

현재 조선 산업의 대형 블록제작 용접공정에서 용접용 캐리지(Carriage)를 이용한 반자동 용접 방법이 많이 사용되고 있다. 여기서의 캐리지는 수평 필렛 용접에서 용접 토치를 이송해 주는 장치이지만, 로봇 용접방법처럼 용접선을 추적하는 기능이 없어 곡선용접에는 사용이 불가능하며, 단순히 직선용접에만 사용할 수 있다. 또, 용접선을 추적하는 기능이 없기 때문에 직선용접에서도 용접오류가 자주 발생하여 이를 수정하는데 많은 시간과 비용이 소요되고 있다. 이에 본 논문에서는 현재 사용하고 있는 캐리지에 스트레인 게이지를 이용한 용접선 추적 센서와 80C196KC 마이크로컨트롤러를 추가 설치하여 직선 및 곡선용접에서 용접선을 자동으로 추적할 수 있는 시스템을 개발하여 사선 모형 및 컨테이너 박스 모형 용접선을 제작하여 추적현상에 대해 고찰하여 보았다.

• 한국공간구조학회논문집
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• 제16권4호
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• pp.75-82
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• 2016

Building hardware joints are welded in most cases, which have risks of fire and explosion. Besides, the secondary damage of the destruction of the welded parts can be caused by the horizontal displacement of the structure due to earthquake or wind load. This paper compared the horizontal displacement following abilities of welded building hardware and non-welded building hardware. To do this, We conducted actual formation shake table test, and checked on the horizontal displacement following ability of structure by comparing their responses to earthquake load. We made the 2m-high framework to examine the responses of the actually constructed building hardwares, and analyzed the displacement responses of the welded-typed, non-welded-typed, and cruciform bracket building hardwares. We conducted the test by increasing acceleration rate until displacement reached 40mm corresponding to allowable relative story displacement II. The result of the test showed that the building hardware using welding work made cracking and breakage on welded connections of welded building hardware, but non-welded building hardware with no use of welding work and cruciform bracket building hardware make no problem, and that non-welded building hardware is superior to that of the welded building hardware in the horizontal displacement following ability due to earthquake or wind load.

• Journal of Welding and Joining
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• 제13권3호
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• pp.8-17
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• 1995

LNG를 저장할 수 있는 탱크는 주로 지상식이거나 반지하식이며 그 용량은 매우 다양하다. 우리나라에서는 지상식 탱크가 평택 인수기지에 10만m$^{3}$급 Membrane Type 6기가 건설되었고 1기는 거의 완성단계이며, 현재 추가로 건설 중인 3기를 포함하면 총 10기의 탱크를 확보하게 된다. 또한 제2인수기지인 인천에도 동급 으로서 9%Ni강을 사용하는 Double Wall Type LNG 탱크 3기를 건설 중이다. 전세계적 으로 볼 때 LNG 저장 탱크의 78%는 지상식으로 Double Wall Type 또는 Membrane 저장 탱크 형식을 취하고 있으나, 최근에는 안전성 측면, 토지 가격의 상승, 토지의 합리적 이용 측면 등을 감안하여 LNG 탱크를 지하화, 대형화하는 추세이다. 본고에서는 Fig. 1과 같은 구조의 Double Wall Type LNG 저장탱크 중 초저온의 LNG에 직접 접하는 저 온용 재료(9%니켈강)로 만들어지는 내조 용접에 대해서 중점적으로 논하기로 하며, 특히 9% 니켈강 Shell Plate Horizontal Joint에 채용되는 Automatic Submerged ARC 용접에 대해 실제 현장 용접 시공상태를 나타내고자 한다.

• Interaction and multiscale mechanics
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• 제4권1호
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• pp.65-83
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• 2011

In this study, two extreme cases of compatibility of the horizontal displacements between the foundation and soil are considered, for which the pressure and settlements of the isolated footings and member end actions in structural elements are obtained using the three dimensional models and numerical experiments. The first case considered is complete slip between foundation and soil, termed as the un-coupled analysis. In the second case of analysis, termed as the coupled analysis, complete welding is assumed of joints between the foundation and soil elements. The model and the corresponding computer program developed simulate these two extreme states of compatibility giving insight into the variation of horizontal displacements and horizontal stresses and their intricacies, for evaluation of the influence of using the interface elements in soil-structure interaction analysis of three dimensional multiscale structures supported by isolated footings.

• Journal of Welding and Joining
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• 제16권5호
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• pp.134-141
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• 1998

In this study, a fillet size for bending fatigue strength of one side fillet welded T-joint, used in box type girder and other welding structure, was investigated by bending fatigue test with or without edge preparation and burn through, with variation of joint shape. As a result, the following conclusions were obtained. (1) In one side fillet welded T-joint, the larger the leg length, the greater the bending fatigue strength. The increase in bending fatigue strength. (2) One side filet welded T-joint with edge preparation showed higher bending fatigue strength than that with twofold-large leg length and without edge preparation. (3) In one side fillet welded T-joint without edge preparation, both manual welding and automatic welding were carried out with same condition. In this case, automatic welding shoed deeper penetration and more increased horizontal leg length than manual welding, so that automatic welding offers grater bending fatigue strength. (4) For one side fillet welded T-joint without edge preparation, the ratio(h/t) of the leg length (h) and the main plate thickness (t) in which toe crack can occur was 1.2 over. (5) In one side fillet welded T-joint with edge preparation, the burn through led to reduced bending fatigue strength. However, this bending fatigue strength was higher than that of one side fillet welded T-joint without edge preparation and with a larger leg length.

• 한국기계가공학회지
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• 제12권6호
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• pp.37-44
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• 2013

Friction stir welding (FSW) is a solid state joining technique that has expanded rapidly since its development in 1991 and has numerous applications in a wide variety of industries. This paper introduces the basic principles of friction stir welding (FSW) and presents a survey of the latest technologies and applications in the field. The basic principles that are discussed include the terminology, tool/workpiece processes, FSW merits and process variants. In particular, the process variants including the rotation speed and traveling speed are discussed, which include the defect-free zone in an oxygen free copper and Al alloy, respectively. Multiple aspects of the FSW machine are developed, including a horizontal 2D FSW machine and a hybrid complex FSW machine. The latest applications are introduced, with an emphasis on the recent advances in the aerospace, automotive, and IT display industries. Finally, the direction for future research and potential applications are examined.

• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.39-45
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• 2014

PURPOSE. The aim of the present study was to evaluate the accuracy of three techniques for correction of cast implant bars. MATERIALS AND METHODS. Thirty cast implant bars were fabricated on a metal master model. All cast implant bars were sectioned at 5 mm from the left gold cylinder using a disk of 0.3 mm thickness, and then each group of ten specimens was corrected by gas-air torch soldering, laser welding, and additional casting technique. Three dimensional evaluation including horizontal, vertical, and twisting measurements was based on measurement and comparison of (1) gap distances of the right abutment replica-gold cylinder interface at buccal, distal, lingual side, (2) changes of bar length, and (3) axis angle changes of the right gold cylinders at the step of the post-correction measurements on the three groups with a contact and non-contact coordinate measuring machine. One-way analysis of variance (ANOVA) and paired t-test were performed at the significance level of 5%. RESULTS. Gap distances of the cast implant bars after correction procedure showed no statistically significant difference among groups. Changes in bar length between pre-casting and post-correction measurement were statistically significance among groups. Axis angle changes of the right gold cylinders were not statistically significance among groups. CONCLUSION. There was no statistical significance among three techniques in horizontal, vertical and axial errors. But, gas-air torch soldering technique showed the most consistent and accurate trend in the correction of implant bar error. However, Laser welding technique, showed a large mean and standard deviation in vertical and twisting measurement and might be technique-sensitive method.