• Title/Summary/Keyword: 파열 강도

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Three Dimensional Ultrasonographic Evaluation with Intra-articular Saline Injection in Rotator Cuff Tear (회전근 개 파열의 수술 전 3차원 초음파 검사에서 관절내 생리식염수 주사 후 검사의 정확도)

  • Yum, Jae-Kwang;Shin, Yong-Woon;Park, Shin-Seung
    • The Journal of Korean Orthopaedic Ultrasound Society
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    • v.2 no.2
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    • pp.62-67
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    • 2009
  • Purpose: The purpose of this study is to find out the accuracy and usability of the three dimensional ultrasonography in measuring the size of the rotator cuff tear, especially before and after the injection of normal saline into the glenohumeral joint. Materials and Methods: 14 patients of rotator cuff tear who were diagnosed and operated from August 2007 to September 2008 were included in this study and authors compared the size of rotator cuff tear measured with three dimensional ultrasonography with the real size measured intraoperatively. In preoperative ultrasonographic evaluation, horizontal and longitudinal length of rotator cuff tear before and after injection of normal saline intraarticularly. During the arthroscopic operation the size of tear was measured by passing a Kirschner wire through a spinal needle and direct measure was performed in open surgery. Results: The average difference was 8 mm in horizontal and 1.9 mm in longitudinal length of tear without saline injection between ultrasonographic and intraoperative measure. The average difference was 4.1 mm in horizontal and 1.6 mm in longitudinal length of tear after the normal saline injection. Conclusion: In three dimensional ultrasonographic evaluation in rotator cuff tear, intraarticular normal saline injection would produce more accurate results.

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Shear Resistance of CIP Anchors under Dynamic Loading: Unreinforced Anchor (선설치앵커의 동적 전단하중에 대한 저항강도: 비보강 앵커)

  • Park, Yong Myung;Kang, Moon Ki;Kim, Dong Hyun;Lee, Jong Han;Kang, Choong Hyun
    • Journal of Korean Society of Steel Construction
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    • v.26 no.1
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    • pp.11-20
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    • 2014
  • The Concrete Capacity Design(CCD) method has been used in the design of anchor since 2001 and Korean design code specify that concrete breakout capacity of CIP anchor under seismic load shall be taken as 75% of static capacity. In this study, an experimental study was performed to evaluate the concrete breakout capacity of unreinforced CIP anchors under dynamic shear force. For the purpose, three static and dynamic shear-loading tests were conducted using 20mm diameter anchors, respectively. The edge distance of 120mm was considered in the tests. In the dynamic tests, 15 cycles pulsating load with 1Hz speed was applied and the magnitude of loading step was increased until concrete breakout failure occurs. From the tests, the concrete breakout capacity under dynamic shear loading showed nearly same capacity by static loading.

Dynamic Shear Strength of Stirrup-reinforced Cast-in Anchors by Seismic Qualification Tests (스터럽 보강 선설치 앵커의 지진모의실험에 의한 동적 전단 저항강도 평가)

  • Kim, Tae Hyung;Park, Yong Myung;Kang, Choong Hyun;Lee, Jong Han
    • Journal of Korean Society of Steel Construction
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    • v.30 no.2
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    • pp.67-76
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    • 2018
  • An experimental study was conducted to evaluate the breakout strength of stirrup-reinforced cast-in anchors under dynamic shear loadings. The shear loadings were applied in the manner specified in the ACI 355.2 and ETAG 001 for the seismic qualification tests. Test specimens were fabricated with M36 anchor (edge distance, 180mm) reinforced with D10 stirrups (spacing, 100mm). The specimens reached almost the breakout strength and thereafter fracture of anchor occurred. Additional tests with M42 anchor (edge distance, 160mm) reinforced with D6 bars (spacing, 100mm) were also conducted. The experimental results showed that the dynamic shear strength was not less than the static resistance. Based on the test results, it was shown that ACI 318 and ETAG 001 specifications estimate the breakout strength of stirrup-reinforced anchors conservatively as more reinforcement is provided.

Effect of External Pressure on the Burst Strength of Steam Generator Tube (증기발생기 전열관의 파열강도에 미치는 외압의 영향)

  • Cho, Sung-Keun;Bae, Bong-Kook;Seok, Chang-Sung
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.353-358
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    • 2004
  • Tracing the study of the burst test of steam generator tube, few studies have been reported to effect of external pressure acting on secondary-side in service condition. In this study the burst tests of Inconel 690TT were conducted in order to evaluate burst strength characteristics under the effect of external pressure. We obtained the result that the burst strength of Inconel 690TT increased when external pressure increased while both total circumferential elongation and uniform burst elongation were not affected. Also, according to the increased of external pressure, the size of the burst opening became smaller and the tear was getting severe.

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A Study on the Concrete Breakout Capacity of CIP Anchor Bolts under Shear Loading (전단력을 받는 선설치 앵커볼트의 콘크리트 파열파괴강도 평가 연구)

  • Park, Yong-Myung;Jeon, Myeong-Hui;Choi, Myung-Kuk;Kim, Cheol-Hwan;Kim, In-Gi
    • Journal of Korean Society of Steel Construction
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    • v.24 no.2
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    • pp.207-215
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    • 2012
  • The 45-degree cone failure theory has been used in concrete anchor bolts design under shear loading, but the CCD (Concrete Capacity Design) method was adopted as a new design method since 2000. However, the method was allowed only for anchor diameters of less than 50mm because it is based on the experimental results of small size anchor bolts. Therefore, it is necessary to develop a rational concrete breakout capacity equation for medium-to-large size anchor bolts with large edge distance. In this study, shear tests on M56 cast-in-place single anchor bolt with edge distance of 350mm were performed using four test specimens. Based on the test results and findings of existing studies, a new equation for the breakout capacity of anchor bolts under shear loading with edge distance of up to 750mm was proposed.

손상된 파이프의 구조 안전성 평가

  • 박재학
    • Bulletin of the Korean Institute for Industrial Safety
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    • v.2 no.1
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    • pp.34-40
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    • 2002
  • 화학설비나 산업설비 또는 국가 기간 설비에서 파이프(pipe)는 중요한 위치를 차지하고 있으며 파이프의 파열은 그대로 대형 사고나 설비 가동의 중단으로 연결되는 경우가 많다. 따라서 파이프의 구조건전성을 유지하는 것은 안전의 확보와 생산 설비의 효율적 운용을 위하여 긴요하다. 파이프 재료 내부에는 재료 제작 시, 또는 파이프 제작 시 발생된 결함이나 사용 중 부식이나 피로 등의 영향으로 생성된 결함이 존재한다. 이러한 결함은 파이프의 강도를 낮추게 되고, 파이프의 잔류강도가 사용압력보다 낮아지게 되면 파이프가 파열하게 된다. 따라서 본 글에서는 파이프에 균열이 존재하거나 손상된 경우의 구조안전성 평가를 위하여 필요한 해석방법에 대하여 살펴본다.(중략)

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A Study on the Vented Gas Explosion Characteristics of Indoor Leakage of the LPG (실내 LPG 누출시 폭발특성에 관한 연구)

  • Oh Kyu-hyung;Kim Hong;Kim Sang-sub;Jo Yoong-do;Jo Jee-whan;Oh Shin-kyu
    • Journal of the Korean Institute of Gas
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    • v.3 no.3 s.8
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    • pp.51-57
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    • 1999
  • A study on the vented gas explosion characteristics were carried out with the liquified petroleum gas(LPG) which is used in domestics and industries fuel. To evaluate a damage by gas explosion and to predict a explosion hazards, a series of experiment have been performed in the regular hexahedron vessel of 270${\iota}$. A side of the vessel was made to setting a polyester diaphragm which was ruptured by explosion to simulate an accidental explosion which ruptured the window by explosion. Experimental parameters were LPG concentration, ignition position, venting area, a strength of diaphragm which was ruptured and distances from venting, Experimental results showed that vented gas explosion pressure was more affected by the diaphragm strength than the gas concentration, and the vented gas explosion pressure and blast wave pressure was increased with decreasing the venting area and increasing the strength of diaphragm. In this research we can find that a damage by vented explosion at the outside can be larger than the inside by blast wave pressure near the venting.

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A Study on the Burst Pressure of Circular Tubes (원형튜브의 파열압력에 관한 연구)

  • 이영신;강문중;조원만
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.6
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    • pp.1056-1063
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    • 1992
  • Burst pressure of right circular tube is predicted using analytic method, and asymptotic instability pressure of circular tube with roundness defect is found using FEM. Burst tests of nearly right circular tube specimens are carried out and predictions are compared with burst pressures and their accuracy is discussed. It is confirmed that FEM is useful for prediction of burst pressure.

Comparison of Cutting and Compression Tests for the Texture Measurement of Chinese Cabbage Leaves (절단시험과 압착시험에 의한 배추잎의 조직감 측정 비교)

  • Lee, Cherl-Ho;Hwang, In-Ju
    • Korean Journal of Food Science and Technology
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    • v.20 no.6
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    • pp.749-754
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    • 1988
  • The texture measurement of Chinese cabbage leaves used for Kimchi preparation were con ducted by cutting and compression test and the results were compared to the sensory evaluation. The cutting force of cabbage leaf stalk increased by blanching or salting, and a maximum cutting force was attained by salting in 15% salt solution for 5 hours. The compression force and recovered height measured by compression test of Chinese cabbage leaf stalk decreased by blanching or salting, and the breaking point disappeared. Treatment with $CaCl_2$ solution increased the cutting force compression force and breaking strength of fresh leaves, but the effect disappeared by salting or blanching. Cutting strength could be used as a parameter indicating the hardness and chewiness of salted cabbage. Compression force and breaking strength could indicate the textural changes of blanched leaves, but were not useful for the measurement of hardness and chewiness of salted leave.

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