• Composites Research
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• v.29 no.2
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• pp.53-59
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• 2016

Aircraft wing structure is used as a fuel tank containing the fluid. Fuel tank and joint parts are consists of composite structure. Hydrodynamic Ram(HRAM) effect occurs when the high speed object pass through the aircraft wing or explosion and the high pressure are generated in the fuel tank by HRAM effect. High pressure can cause failure of the fuel tank and the joint parts as well as the aircraft wing structure. To ensure the aircraft survivability design, we shall examine the behavior of the joint parts in HRAM effect. In this study, static tensile tests were conducted on four kind of the composite T-Joints. The failure behavior of the composite T-joint was examined by strain gauges and high speed camera. We examine the validity of the Finite Element Modeling by comparing the results of FEA and static tensile tests. The failure stresses and failure pressure of the composite T-Joint were calculated by FEA.

• Steel and Composite Structures
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• v.18 no.4
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• pp.1045-1062
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• 2015

Concrete-filled circular t steel tubular joints (CFSTJs) in practice are frequently subjected to fluctuated loadings caused by wind, earthquake and so on. As fatigue crack is sensitive to such cyclic loadings, assessment on performance of CFSTJs with crack-like defect attracts more concerns because both high stress concentration at the brace/chord intersection and welding residual stresses along weld toe cause the materials in the region around the intersection to be more brittle. Once crack initiates and propagates along the weld toe, tri-axial stresses in high gradient around the crack front exist, which may bring brittle fracture failure. Additionally, the stiffness and the load carrying capacity of the CFSTJs with crack may decrease due to the weakened connection at the intersection. To study the behaviour of CFSTJs with initial crack, experimental tests have been carried out on three full-scale CFCST T-joints with same configuration. The three specimens include one uncracked joint and two corresponding cracked joints. Load-displacement and load-deformation curves, failure mode and crack propagation are obtained from the experiment measurement. According to the experimental results, it can be found that he load carrying capacity of the cracked joints is decreased by more than 10% compared with the uncracked joint. The effect of crack depth on the load carrying capacity of CFCST T-joints seems to be slight. The failure mode of the cracked CFCST T-joints represents as plastic yielding rather than brittle fracture through experimental observation.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.35-44
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• 2009

The purpose of this paper is to describe experimental results about the T-joint welding of the high power continuous wave (CW) fiber laser for SAPH steel plate for seat frame of car. The seat rail is a part of seat frame of cars. The assembling method is mostly fix up using a bolt and nut. But this assembling method has many demerits in productivity such as increasing work process and material cost. This paper presents an experimental study about Laser T-Joint weldability of seat rail. Laser welding has many advantages in lightness and saving material costs of seat frame. The laser beam was moved along the work pieces by six axis robot with process optical fiber. The laser beam is focused with a welding head within incident angle $15{\sim}45^{\circ}$ for the purpose of the T-joint welding through two side full penetration. The range of the root gap size is less than ${\leq}0.4mm$. Optical microscopy SEM were performed to observe the micro structures and determine the structures of welded zone.

• International Journal of Concrete Structures and Materials
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• v.5 no.1
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• pp.57-64
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• 2011

An extensive database has been constructed of reinforced concrete (RC) beam-column connection tests subjected to cyclic lateral loading. All cases within the database experienced joint shear failure, either in conjunction with or without yielding of longitudinal beam reinforcement. Using the experimental database, envelope curves of joint shear stress vs. joint shear strain behavior have been created by connecting key points such as cracking, yielding, and peak loading. Various prediction approaches for RC joint shear behavior are discussed using the constructed experimental database. RC joint shear strength and deformation models are first presented using the database in conjunction with a Bayesian parameter estimation method, and then a complete model applicable to the full range of RC joint shear behavior is suggested. An RC joint shear prediction model following a U.S. standard is next summarized and evaluated. Finally, a particular joint shear prediction model using basic joint shear resistance mechanisms is described and for the first time critically assessed.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.79-89
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• 2007

Purpose: The purpose of this study was to identify the effects of a physical exercise program using elastic bands in rural area women. Method: This study adopted a pre-post test design. The subjects were 89 rural area women who were selected from four community health care centers. The physical exercise program was executed 30 times for 10 weeks (3 times a week) from August 23 to October 31, 2003. Results: There was a significant difference in the attitude of physical exercise (t=-5.517, p=.000). In the degree of joint pain, there were significant differences in the flextion and extension of the shoulder joint (t=2.557, p=.020; t=5.625, p=.000), and there was a significant difference in the flextion of the knee joint (t=4.747, 0=.000) but there was no significant difference in the extension of the knee joint (t=1.795, p=.083). Conclusion: Physical exercise programs need to be implemented and spread continuously.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1058-1062
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• 1996

The assessments of weld defects by fracture mechanics are performed for design of welded Joints. In general, butt, T-type, and L-type welded joint are useful for welding structure. When linear weld defects are in welded joint, stress intensity factors for each joints are calculated by finite element method. Analysis results are shown for the fracture modes and characteristics of joint types. And they are founded for the weaken order of welded joints being T-type, butt, L-type.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.166-173
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• 1998

The evaluation of joint fatigue strength of light weight materials for an electrical vehicle body has been performed through T-peel joint tests with the design parameters such as joint style, adherend type, adherend thickness, adhesive thickness, and various adhesives. Fatigue strength was evaluated through 5-Hz, tension-tension, load controlled test with the zero stress ratio. It was observed that the fatigue strength of the joint increases with the increase of the adherend thickness. With the increase of the adhesive thickness, however, the fatigue strength of the joint increases insignificantly. An aluminum-FRP adherend combination shows much higher fatigue strength than an aluminum-aluminum adherend combination. The results of fatigue tests were found to be consistent with those of static tests.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.223-225
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• 2005

In order to demonstrate the friction stir weldability of the Al 6061 T-6 unequal thickness joint and determine optimum welding parameters, the relations between welding parameters and properties of the joints have been studied in this paper. The experimental results showed that the tensile properties of the joints are affected by the welding heat inputs and tool shape. In this study, the maximum ultimate strength of the as-welded joint is equivalent to 78% and 18hour aged joint is equivalent to 93% that of the base metal. Though the voids-free joints are fractured at the thermally affected zone on the advancing side, the fracture occurs at the weld center when the void defects exist in the joints.

• Investigative Magnetic Resonance Imaging
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• v.23 no.3
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• pp.228-240
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• 2019

Purpose: The aim of this study is to evaluate the T2 value of the articular cartilage of the glenohumeral joint in rotator cuff disease displayed on 3.0T MRI and to apply it in clinical practice. Materials and Methods: This study involved sixty-two patients who underwent shoulder MRI containing T2 mapping. The mean T2 value was measured by placing a free hand ROI over the glenoid or humeral cartilage from the bone-cartilage interface to the articular surface on three consecutive, oblique coronal images. The drawn ROI was subsequently divided into superior and inferior segments. The assessed mean T2 values of the articular cartilage of the glenohumeral joint were compared and evaluated based on the degree of rotator cuff tear, the degree of fatty atrophy of the rotator cuff, and the acromiohumeral distance. Results: ICC values between two readers indicated moderate or good reproducibility. The mean T2 value for the articular cartilage of the glenoid and humeral head cartilage failed to show any significant difference based on the degree of rotator cuff tear. However, the mean T2 values of articular cartilage, based on fatty atrophy, tended to be higher in fatty atrophy 3 or fatty atrophy 4 groups while some subregions displayed significantly higher mean T2 values. There was no correlation between the acromiohumeral distance and the mean T2 values of the articular cartilage of the glenoid and humeral head. Conclusion: T2 mapping of the glenohumeral joint failed to show any significant difference in quantitative analysis of the degenerative change of the articular cartilage based on the degree of rotator cuff tear. However, it also offers quantitative information on the degenerative change of cartilage of the glenohumeral joint in patients with rotator cuff tear and severe fatty atrophy of the rotator cuff.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.53-61
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• 2015

The tension type joint is a mechanically very efficient connection method, as it directly uses the load capacity of base metal or high tension bolt, the reduction of the number of drilling hole and fastening and the fatigue resistance. It is applied to the joint of girder and cross beam, horizontal joints of towers, beam to column joints, the secondary member joints of deck floor ends, and brackets. In this paper, static load tests for the T-type tension joint were conducted to investigate the structural behavior of the joint. The parameters were bolt diameter, flange thickness, and the reduction of clamping force of the joint. The failure modes and load capacity of joints and the effects of flange thickness, bolt diameter and clamping force were investigated.