• Title/Summary/Keyword: joint test

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An Experimental Study on the Effects of Bolted Connection Type on the Block Shear Failure (볼트이음방식의 블록전단파괴에 미치는 영향에 대한 실험적 연구)

  • Lee, Chin-Ok;Park, Gyung-Hyeon;Moon, Jiho;Lee, Hak-Eun;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5566-5571
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    • 2012
  • Block shear failure is one of limit states, and demands great caution in designing the tension member or connection joint of steel structures. From many studies and design specification, it is shown that the effect of the bolted connection type on the block shear failure was not considered. In order to investigate the effect of the bolted connection type(bearing type connection and slip critical connection) on the mode/strength of the block shear failure, tensile experiment is conducted in this study. Differences about the failure mode according to the design specification, bearing type connection, and slip critical connection are proposed from the analysis of test results. The variation of the block shear failure strength due to the frictional force in the slip critical connection is also investigated.

Progressive Filure Analysis of Composite Double Bolted Joints using Gradual Degradation Model (점진적 강성 저하 모델을 이용한 복합재 이중 볼트 체결부의 점진적 파손 해석 연구)

  • Kim, Pyunghwa;Kim, Sungmin;Doh, Sungchul;Yoon, Donghyun;Park, Jungsun
    • Journal of Aerospace System Engineering
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    • v.13 no.6
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    • pp.26-35
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    • 2019
  • In this paper, progressive failure analysis is performed on composite joints widely used in various industries such as the aerospace industry. The analysis was conducted on single bolted joints to confirm its reliability and in succession on double-bolted composite joints as well to study the characteristics of progressive failure. Hashin failure criteria and EGDM (energy based gradual degradation model) were used for the analysis. Failure variables are defined by four failure modes, respectively. According to the variables, stiffness degradation has been calculated. As a result of comparing the test and analysis results of single-bolted joints, the error was below 5% and it showed that the analytical results are rather credible. Also, the parametric analysis consequences were obtained conducting the process-progressive failure analysis on the double-bolted composite joints considering edge-distance ratio (e/d ratio) and bolt spacing.

Study on the Bearing Capacity of Helical Pile through Field Load Tests (현장재하시험을 통한 헬리컬파일의 지지력에 관한 연구)

  • Kwon, Gi-Ryeol;Jang, Jeong-Wook;Cho, Song-Hyun
    • The Journal of the Korea Contents Association
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    • v.20 no.11
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    • pp.669-675
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    • 2020
  • This research has focused on comparing the capacity predicted by the theoretical formula with the one measured by field load tests to examine characteristics of the bearing capacity of a helical pile. The helical pile is featured by a central shaft with one or more helical-shaped bearing plates. Being established by a small rotary attached to an excavator that applies toque, the helical piles can be readily constructed at narrow sites, especially in an urban area with relatively less noise than the others requiring driving and excavation. Although many cases of the helical pile constructions can be recently found, the bearing capacity of the pile has been limitedly studied. To this end, this contribution analyzes and presents comprehensive results of the ten field loading tests with an application of different parameters depending on joint condition and specification of the helical piles, and types of tests and grouting.

Is the Frozen Shoulder Classification a Reliable Assessment?

  • Gwark, Ji-Yong;Gahlot, Nitesh;Kam, Mincheol;Park, Hyung Bin
    • Clinics in Shoulder and Elbow
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    • v.21 no.2
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    • pp.82-86
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    • 2018
  • Background: Although a common shoulder disease, there are no accepted classification criteria for frozen shoulder (FS). This study therefore aimed to evaluate the accuracy of the conventionally used FS classification system. Methods: Primary FS patients (n=168) who visited our clinic from January 2010 to July 2015 were included in the study. After confirming restrictions of the glenohumeral joint motion and absence of history of systemic disease, trauma, shoulder surgery, shoulder muscle weakness, or specific x-ray abnormalities, the Zuckerman and Rokito's classification was employed for diagnosing primary FS. Following clinical diagnosis, each patient underwent a shoulder magnetic resonance imaging (MRI) and blood tests (lipid profile, glucose, hemoglobin A1c, and thyroid function). Based on the results of the blood tests and MRIs, the patients were reclassified, using the criteria proposed by Zuckerman and Rokito. Results: New diagnoses were ascertained including blood test results (16 patients with diabetes, 43 with thyroid abnormalities, and 149 with dyslipidemia), and MRI revealed intra-articular lesions in 81 patients (48.2%). After re-categorization based on the above findings, only 5 patients (3.0%) were classified having primary FS. The remaining 163 patients (97.0%) had either undiagnosed systemic or intrinsic abnormalities (89 patients), whereas 74 patients had both. Conclusions: These findings demonstrate that most patients clinically diagnosed with primary FS had undiagnosed systemic abnormalities and/or intra-articular pathologies. Therefore, a modification of the Zuckerman and Rokito's classification system for FS may be required to include the frequent combinations, rather than having a separate representation of systemic abnormalities and intrinsic causes.

Analysis of ground reinforcement effect using fracturing grouting (침투 및 할렬주입에 의한 지반보강 효과에 관한 연구)

  • Lee, J.S.;Lee, I.M.;Chung, H.S.;Lee, D.S.
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.5 no.4
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    • pp.349-360
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    • 2003
  • A practical modeling approach has been proposed in this study to better understand the behavior of penetration grouting which is normally applied to the jointed rock masses to increase the bearing capacity and to reduce the ground water flow into the tunnel. Based on Bingham model together with a steady-state flow of the grout, penetration model is simulated in the commercial package called UDEC and, injection pressure as well as joint thickness are found to be the main parameters to determine the range of grout spread. Another numerical model on fracturing grouting is also suggested and, in this case, the tensile strength as well as cohesion of the rock masses are proven to be the major factors to decide the fracturing mechanism of the rock masses. The reinforcement effect of the grout-reinforced rock masses is calculated from the suggested algorithm on orthotropic material model and it is found that the directional stiffness of reinforced rock masses is increased up to 3 to 4 times compared with original jointed rock masses. Future work will be concentrated on the water control around the tunnel by the grout injection and a model test will also be performed to verify the suggested methods developed in this study.

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Osteomyelitis following Domestic Animal Bites to the Hand: Two Case Reports and Practical Guidelines

  • Lim, Jung Soo;Byun, Jin Hwan;Min, Kyung Hee;Lee, Hye Kyung;Choi, Yun Sun
    • Archives of Plastic Surgery
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    • v.43 no.6
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    • pp.590-594
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    • 2016
  • Recently, the number of cases of animal bite wounds has increased significantly in concordance with an increase in the pet population around the world. The authors report two rare cases of osteomyelitis of the phalanx following cat and dog bites. On initial physical examination, signs of a severe infection were observed. Radiographs of both patients showed the presence of osteomyelitis, and in one of the patients, the diagnosis was confirmed with a bone biopsy. After use of empirical antibiotics, intravenous antibiotic therapy that matched the identified bacterium's sensitivity was initiated, and at the same time, secure dressing including debridement was performed to induce secondary healing. In addition, the patients were closely monitored with serial X-rays, and culture and blood test follow-up. One patient fully recovered without sequelae, but the other patient suffered a loss of distal interphalangeal joint motion. When dealing with bite wounds located on the hand, it is important to visit the hospital as soon as possible and receive the appropriate treatment early. Moreover, to prevent severe complications such as osteomyelitis, it is important to administer antibiotic therapy to which the cultured bacteria are sensitive, along with proper wound management and prophylactic antibiotic treatment.

A Study of Comparative the Chewing Ability and Oral Health Status of some Elderly People (일부 노인의 구강상태와 저작능력 비교연구)

  • Choi, Eunsil;Lee, Youngsoo
    • Journal of The Korean Society of Integrative Medicine
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    • v.6 no.1
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    • pp.25-33
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    • 2018
  • Purpose : The present study aimed to investigate the of the based on their oral health status and the study findings will provide the basic data for establishing future oral health related policies for the elderly. Methods : A total of 50 elderly participants were selected for the study. Oral examinations were performed by a single trained dental hygienist, the oral health status was classified according to the use of dentures, presence of temporo-mandibular joint (TMJ) noise, presence of TMJ pain, presence of trismus, presence of preferred chewing, and number of residual teeth. An oral health-related survey using the in-person interview method was conducted by two dental hygienists and 30 types of foods were selected for the assessment of chewing ability. For data analysis, the Mann-Whitney U test and Spearman's Rho analysis were performed to investigate the association between oral health status and chewing ability. Result : The results of the present study revealed that there was a statistically significant positive (+) correlation between the number of residual teeth and chewing abilities. In other words, as the number of residual teeth increased, chewing ability increased as well, with the differences being statistically significant. Conclusion : Improvement of oral health in the elderly is a fundamental aspect of healthy aging. Therefore, the implementation of more efficient oral health care policies for the elderly is required as We move toward a super-aged society.

Infrared Thermal Imaging in Patients with Medial Collateral Ligament Injury of the Knee - A Retrospective Study

  • Yang, HyunJung;Park, HaeIn;Lim, Chungsan;Park, SangKyun;Lee, KwangHo
    • Journal of Pharmacopuncture
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    • v.17 no.4
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    • pp.50-54
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    • 2014
  • Objectives: Digital infrared thermographic imaging (DITI) has been used widely for various inflammatory diseases, circulatory diseases, skin diseases, musculoskeletal diseases and cancers. In cases of ligament injury, obviously the temperature of the damaged area increases due to local inflammation; however, whether the temperature also increases due to DITI has not been determined. The purpose of the present study was to identify whether or not the changes of temperature in patient's with medial collateral ligament injury were really due to infrared thermography and to determine the applicability of DITI for assessing ligament injuries. Methods: Twenty patient's who underwent DITI for a medial collateral ligament injury from September 2012 to June 2014 were included in the current study. The thermographic images from the patient's knees were divided to cover seven sub-areas: the middle of the patella, and the inferomedial, the inferolateral, the superomedial, the superolateral, the medial, and the lateral regions of patella. The temperatures of the seven regions were measured, and the temperature differences between affected and unaffected regions were analyzed by using the Wilcoxon signed rank test. Results: The 20 patient's were composed of 14 women (70%) and 6 men (30%), with a mean age of $62.15{\pm}15.71$ (mean${\pm}$standard deviation (SD)) years. The temperature of the affected side, which included the middle of the patella, and the inferomedial, the superomedial, the superolateral, and the medial regions, showed a significant increase compared to that of the unaffected side (P < 0.05). The inferolateral and the lateral regions showed no significant changes. Conclusion: Our study results suggest that DITI can show temperature changes if a patient has a ligament injury and that it can be applied in the evaluation of a medial collateral ligament injury.

Development of a Height Adjustment Method of Prefabricated Individual Footing for the Leveling of Unit Modular Structural System (유닛모듈러 건축구조물의 수평 정밀도 확보를 위한 Pre-Fab 독립기초 높이조절 공법 개발)

  • Jun, Young-hun;Kim, Kyoon-Tai;Chae, Myung-Jin
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.6
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    • pp.631-639
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    • 2015
  • In the unit modular construction, the unit module prefabricated in a factory with a high level of accuracy does not fit completely onto the ground-joint junction due to the low accuracy of the ground work. This difference in the level of accuracy can cause diverse problems, such as twisting the upper unit modules and loosening the connection between the module and the footing. On this background, the aim of this study is to develop a technique for adjusting the height of the prefabricated individual footing. To accomplish the aim, a height adjustment method using bolts and nuts is proposed, and a shop drawing and the construction sequence are also presented in this study. The structural safety is verified through a structure simulation. In the future, research will be conducted on a mock-up test of the height adjustment method developed in this study, and an analysis of economic feasibility will be performed in order to verify its constructability and usability.

Effect of Diamond Taping Applied to the Elbow Joint on Wrist Extensor Muscle Activity in Healthy Subjects (팔꿉관절 부위에 적용한 다이아몬드 테이핑이 정상인의 파악력 수준별 손목 폄근의 근활성도에 미치는 영향)

  • Huang, Tian-zong;Kim, Suhn-yeop
    • Physical Therapy Korea
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    • v.27 no.2
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    • pp.118-125
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    • 2020
  • Background: Lateral epicondylitis (LE) is the most common chronic musculoskeletal pain condition of the upper extremities. LE is often related to forceful grip activities that require isometric contraction of the wrist extensors. A previous study evaluated the effect of the diamond taping technique on grip strength and pain; however, there has been no report on the change in the electromyography (EMG) findings of wrist extensors. Objects: The aim of this study was to investigate the effect of diamond taping technique, using a rigid tape, on the EMG activities of the extensor carpi radialis (ECR) during grip activities. Methods: Twenty-four healthy subjects (mean age = 21.50 ± 2.76 years) volunteered to participate in this study. The subjects were instructed to perform forceful grip activities with and without diamond-type taping on the origin area of the ECR. Grip strength tests were performed at 100%, 75%, 50%, and 25% for maximal isometric contraction force. EMG data were collected from the ECR. Repeated measure analysis of variance was used to analyze the effect of grip force and taping (with and without). Statistical significance levels were set at α = 0.05. Comparison of the results with and without taping at different grip force were analyzed using independent t-test. Statistical significance levels were set at α = 0.01. Results: Statistically significant association was observed between the taping application and forceful grip activity as revealed by the EMG data of the ECR (p < 0.05). EMG of the ECR significantly reduced for all muscle strength levels (p < 0.01) after taping. Conclusion: This study shows an impressive effect of the diamond taping technique, using rigid tape, on wrist extensors during grip activities. Decreasing muscle activity via this taping approach could be utilized to enhance pain-free grip force and reduce pain in patients with LE. Our study suggested that this taping technique could be considered as an effective management strategy of LE.