• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.1
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• pp.31-36
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• 2014

This paper shows the feasibility of using carbon-fiber-reinforced polymer (CFRP) composite materials for manufacturing automotive coil springs. For achieving weight reduction by replacing steel with composite materials, it is essential to optimize the material parameters and design variables of the coil spring. First, the shear modulus of a CFRP beam model, which has $45^{\circ}$ ply angles for maximum torsional stiffness, was calculated and compared with the test results. The diameter of the composite spring was predicted to be 17.5 mm for ensuring a spring rate equal to that when using steel material. Finally, a finite element model of the composite coil spring with $45^{\circ}$ ply angles and 17.5 mm wire diameter was constructed and analyzed for obtaining the static spring rate, which was then compared with experimental results.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.118-124
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• 2006

SThe rigidities of bridge substructures are the important data in the rail-bridge interaction analysis in Korean High -Speed Railway. This experimental study is being performed because of followings. 1) More correct longitudinal stiffness of the structure including substructure should be considered in the calculation of stresses in rails. 2) There are many uncertainties in the design and construction of the piers and foundations. 3) Actual guideline for the rigidities of piers and foundations in the design is necessary. 4) Measurement on the rigidity of pier according to the types of piers, foundations and soil-conditions is needed. Curve for estimating the total rigidity of substructure will be obtained through this and further experimental studies. It may be used in the analysis of Korean High-Speed Railway bridge and then, longitudinal stresses in the rails can be estimated more accurately. One pair of piers, which consist of pot-bearing for fixed support and pad-bearing for movable support, are loaded by steel frame devices with steel wire ropes and hydraulic jack. The responses which are measured at each loading stages in those field tests are displacements and tilted angles on the top and bottom of piers. This study is being performed testing and analysis about several piers in the construction field.

• Journal of the Korean Arthroscopy Society
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• v.12 no.3
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• pp.211-216
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• 2008

Purpose: The frequency of foreign body in the knee joint is not as high, but it sometimes required wide or multiple arthrotomy in order to remove, which can baffle the surgeon in some ways. Our study is to evaluate for effectiveness of arthroscopic retrieval for intra-articular foreign body in the knee joint. Materials and Methods: The 22 patients(16 males, 6 females) had received arthroscopic foreign body retrieval in the knee joint from March 1983 to September 2006. The causes of foreign bodies of the knee joint were 7 of trauma (31.9%) related cases, 13 of surgery related cases (59.0%), 2 found during follow up after operation (8.1%) in pathologies of foreign body. Results: There were 15 of metal showed the most percentage (68.1%), 7 of non-metal (31.9%) in types of foreign bodies, and others included bullet, suture material, pencil lead, broken wire etc. All cases were used by arthroscopic techniques. All foreign bodies were removed easily and were showed no complication such as postoperative joint stiffness. Conclusion: Arthroscopic foreign body retrieval in the knee joint is effective surgery in terms of easy access to foreign body and less postoperative complication.