• The Korean Journal of Pain
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• v.21 no.1
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• pp.1-10
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• 2008

Spinal joint pain syndrome is composed of atlanto-occipital, atlanto-axial, facet, and sacro-iliac joints pain. The syndrome is characterized as referred pain which is originated from deep somatic tissues, which is quietly different from radicular pain with dermatomal distribution originated from nerve root ganglion. The prevalence of facet joint pain in patients with chronic spinal pain of cervical, thoracic, and lumbar regions has been known 56%, 42%, and 31% as in order. It is generally accepted in clinical practice that diagnostic blocks are the most reliable means for diagnosing spinal joints as pain generators. The sacroiliac joint has been shown to be a source of 10% to 27% of suspected cases with chronic low back pain utilizing controlled comparative local anesthetic blocks. The treatment of spinal joints ideally consists of a multimodal approach comprising conservative therapy, medical management, procedural interventions, and if indicated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10b
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• pp.107-114
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• 2003

Although cross rolling process has many advantages in forging a joint shaft, an automotive component of front axle unit, subsequent process is necessary to straighten its bending during forging process. In this paper the bending minimization of the joint shaft was studied to eliminate such an additional process. First of all, a characteristic diagram was used to find out factors affecting the bending of the shaft. Also design of experiments was utilized for estimating the influence of those factors. It was found that the phase angle, which is the difference in starting positions between upper and lower dies, was important to minimize the bending of joint shaft and die cooling is necessary to diminish the distribution of bending.

• International Journal of Concrete Structures and Materials
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• v.5 no.1
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• pp.11-18
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• 2011

Carbonation in RC (reinforced concrete) structure is considered as one of the most critical deteriorations in urban cities. Although RC column has one mix condition, carbonation depth is measured spatially differently due to its various environmental and internal conditions such as sound, cracked, and joint concrete. In this paper, field investigation was performed for 27 RC columns subjected to carbonation for eighteen years. Through this investigation, carbonation distribution in sound, cracked, and joint concrete were derived with crack mappings. Considering each related area and calculated PDF (probability of durability failure) of sound, cracked, and joint concrete through Monte Carlo Simulation (MCS), repairing timings for RC columns are derived based on several IPDF (intended probability of durability failure) of 1, 3, and 5%. The technique of equivalent probability including carbonation behaviors which are obtained from different conditions can provide the reasonable repairing strategy and the priority order for repairing in a given traffic service area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.11 s.242
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• pp.1488-1493
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• 2005

In this study, fatigue tests to obtain S-N curves and FE analyses to obtain structural stress concentration factors were conducted for the two types of cruciform fillet welded joints, that is, load-carrying and non load-carrying types. Then we changed the obtained S-N curve of load carrying joint to that based on hot spot stress. As a result, the S-N curve of load carrying joint based on hot-spot stress was almost exactly coincided with that of non load-carrying joint based on nominal stress. So we have conducted that the fatigue strength of a welded joint with different geometry from the non stress distribution along the expected crack path.

• Advances in aircraft and spacecraft science
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• v.5 no.3
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• pp.401-410
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• 2018

The aim of this work is to optimize the geometrical parameters as the adhesive thickness and the beveled angle to reduce the edge effect of the scarf and V bounded joint. A finite element analysis is done to define the generated stresses in the bounded joint. The geometrical optimum is obtained using the Experimental Design Method. Results show that the double scarf (V) joint is better than the simple scarf bounded joint.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.59-69
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• 2015

This study examined the magnitude and distribution of earth pressure on the support system in a jointed rock mass due to the different joint sets as well as varying the rock type and joint condition (joint shear strength and joint inclination angle). Based on a physical model test and its numerical simulation, a series of numerical parametric analyses were conducted using a discrete element method. The results showed that the induced earth pressure was affected significantly by a joint set depending on the inclusion of the joint inclination angle, which induces a joint sliding condition, but the number of joint sets alone was not important, even though the earth pressure could be increased slightly as the number of joint sets is increased. In addition, the study results were compared with Peck's earth pressure for soil ground, which indicated that the earth pressure in a jointed rock mass could be considerably different from that in soil ground. The study suggests that the effects of joint sets as well as rock type and joint condition are important factors affecting the earth pressure in a jointed rock mass and they should be considered when designing a support system in a jointed rock mass.

• Journal of Distribution Science
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• v.14 no.10
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• pp.137-146
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• 2016

Purpose - Korean agriculture is facing internal and external environmental changes and the need for secure stable outlets. Active participation and mutually beneficial cooperation between enterprises and agricultural is necessary for a win-win situation. This study investigates the case for distribution cooperation and a cooperative system. To respond to the diverse needs of consumers and market reclamation, there is a need to analyze and categorize distribution cooperation. Research design, data, and methodology - A literature study, relevant interviews with enterprises, and meetings with local government practices were conducted. A survey frame was derived through the participation of agricultural enterprises and distribution cooperation models were categorized identifying win-win cooperation and best practices. It was organized on the basis of six best practice examples of distribution cooperation between industry and agricultural sectors, divided into three types: opening distribution channels, exporting cooperation, and developing new products. Results - An innovation management system that can adapt to environmental changes and problems of agriculture is necessary. A company has to supply high-quality agricultural products reliably to meet the preferences of consumers by introducing products that promote domestic market differentiation. In addition, consumers are choosing a variety of products that may include not only high quality products but also local products and safe products. The main areas of cooperation are the direct provision of agrifood raw materials to consumers. Next, would be to help agricultural sectors distribute and pioneer international markets. The ideal step for distribution cooperation is the joint investment in new products by business and agriculture. Conclusions - Agriculture and win-win cooperation with enterprises is in an early stage of social contribution. To implement a distribution cooperation model between business and agricultural sectors, it is crucial to establish a structured support system including joint councils. Additional requirements include strengthening agricultural capacities, creating a legal basis for provision, and producing a win-win cooperation environment. The promotion of win-win cooperation and agricultural enterprises needs to exist in various forms in order to establish a different type of incentive system.

• Journal of Ocean Engineering and Technology
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• v.17 no.2
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• pp.34-39
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• 2003

Recent deepwater offshore structures in the Gulf of Mexico utilize butt welded tubular joints. Application of a welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical, as the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimation of the fatigue behavior of these tubular members in the design stage is generally condrcted by using S-N curves, as specified in the codeds and standards. Applying the stress concentration factor of the welded structure to the S-N approach often results in a very conservative assessment, because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fatigue life analysis using fracture mechanics has been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. Still, there is inconsistency when designing tubular joints using a conventional S-N approach and when specifying weld flaw acceptance criteria using fracture mechanics approach. This study developed fatigue curves that are consistent with both the S-N approach and the fracture mechanics approach. Accounting for non-uniform stress distribution and threshold stress intensity factor were key parameters in relating both approaches. A series of S-N curves, generated from the fracture mechanics approach, were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02 ). The new curves for tubular joint agree very well with the experimental results. The comparison also indicated the degree of conservatism built into the API X design curve.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.214-221
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• 1999

Spot welding is very important and useful technology in fabriaction of the thin sheet structure such as the automobile, train and air craft, Because fatigue strength of the spot welding point is however considerably lower than base metal due to stress concentration at the nugget edge, reasonable fatigue strength evaluation of spot welded lap joint is very important to estimate the reliability and durability of th spot welded structure and to establish a criterion of ling life fatigue design. For reasonalbe fatigue strength evaluation, it is necessary to estimate the fatigue strength of spot welded lap joints, systematically. So far, many investigators have numerically and experimentally studied on the systematic fatigue strength estimation for various spot welded lap joints, and the methods suggested has been considerably accumulated. By the way, for applying them in practical fatigue design of the thin sheet structure fabricated by spot welding ,it is also necessary to verify their efficiency and reliability on the predicted results, Therefore, in this study, a statistical fatigue strength estimation method for spot welded lap joints was developed by using the Weibull probability distribution function. From the result, it was found that fatigue strength and fatigue life of the spot welded lap joints having various dimension were able to be statically predicted . And also, a reliable criterion for long life fatigue design of the spot welded lap joint could be established.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.69-74
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• 2003

Recent deepwater offshore structures in the Gulf of Mexico utilize butt welded tubular joints. Application of a welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical, as the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimation of the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves, as specified in the codes and standards. Applying the stress concentration factor of the welded structure to the S-N approach often results in a very conservative assessment, because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fatigue life analysis using fracture mechanics has been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. Still, there is inconsistency when designing tubular joints using a conventional S-N approach and when specifying weld flaw acceptance criteria using fracture mechanics approach. This study developed fatigue curves that are consistent with both the S-N approach and the fracture mechanics approach. Accounting for non-uniform stress distribution and threshold stress intensity factor were key parameters in relating both approaches. A series of S-N curves, generated from the fracture mechanics approach, were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02). The new curves for tubular joint agree very well with the experimental results. The comparison also indicated the degree of conservatism built into the API X design curve.