• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.128-134
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• 2021

A press-fitted shaft is an essential part used in industrial machines, and it is generally used to transmit large quantities of power. Very high contact pressure occurs at the end parts of the contact between the shaft and boss, which are press-fitted shaft components. Such contact pressure not only damages the contact surface of a press-fitted shaft but also reduces its fatigue strength. To improve a press-fitted shaft's fatigue strength, the contact pressure on the contact surface, which directly affects the fatigue strength, should be minimized. Thus, in this study, the design configuration optimization of the end part of the boss was based on the approximate optimization method and was aimed at minimizing the contact pressure at the end of a press-fitted shaft. Comparison of the contact pressure and the contact stress of a conventional press-fitted shaft with those of the optimized press-fitted shaft showed that the boss design of the optimized press-fitted shaft effectively improved the fatigue life.

• Bulletin of the Society of Naval Architects of Korea
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• v.22 no.1
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• pp.31-37
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• 1985

In ship's structure, deck and bottom plate are main strength member subjected to the inplane load due to longitudinal bending, i.e. tensile and/or compressive load. The deck and bottom plate are subdivided into many plate members by stiffeners and girders longitudinally and transversely. Since the plate members are thin, it is likely to be collapsed under compressive load, and when we consider the local strength of deck and bottom, the plate members play an important role in the longitudinal strength. Therefore the precise analysis of their compressive ultimate strength is required for the optimal design of ship's structures. In this paper, the modified analytical method using the incremental form of principle of virtual displacement is introduced to determine the compressive ultimate load of plate members. The results by the present method is satisfactory, and the present method is more effective and economical than the finite element method.

• Computers and Concrete
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• v.28 no.6
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• pp.621-634
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• 2021

For the reliable strut-and-tie model (STM) design of disturbed regions of concrete members, structural designers must accurately determine the strength of concrete struts to check the strength conditions of a selected STM el and the anchorage of reinforcing bars in nodal zones. In this study, the author proposed a consistent numerical method for strut strength, applicable to all two-dimensional STMs. The proposed method includes the effects of a biaxial stress state associated with tensile strains in reinforcing bars crossing a strut, deviation angle between strut orientation and compressive principal stress flow, and degree of confinement provided by reinforcement. The author examined the method's validity through the STM prediction of the ultimate strengths of 517 reinforced concrete (RC) deep beams, 24 RC panels, and 258 RC corbels, all tested to failure.

• Korean Journal of Metals and Materials
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• v.49 no.9
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• pp.739-745
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• 2011

Beta-type alloys are the most versatile class of titanium alloys. They offer the highest strength to weight ratios and very attractive combinations of strength, toughness, and fatigue resistance inlarge cross sections [1]. The present study was made to obtain useful information for the design of ${\beta}$-type titanium alloys with high-strength properties by using the $DV-X{\alpha}$ method. Employing two calculated parameters, the bond order (Bo) and the d-orbital energy level (Md) of alloying elements in ${\beta}$-type titanium alloy was introduced and used for prediction of mechanical properties. Thus, high-strength titanium alloys were designed by calculating the Md and Bo values of the previous and present titanium alloys.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.3
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• pp.183-190
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• 2019

Recent changes in the construction method of piles to minimize noise, along with the development of high-strength reinforcement, have provided an economical high performance RC pile development to compensate for the disadvantages of existing PHC piles. In this study, a methodology for the development of cross - section details of high performance RC piles of various performances is presented by freely applying high strength steel and concrete. This study suggested a technique for calculating bending moments for a given axial force corresponding to the allowable crack widths and this can be used for serviceablity check. In calculating the design shear force, the existing design equation applicable to the rectangular or the I section was modified to be applicable to the hollow circular section. In particular, in the limit state design method, the shear force is calculated in proportion to the axial force, and the procedure for calculating PV diagram is established. Last, the section details are determined through PM diagrams that they have the similar flexural and axial-flexural performances of the PHC pile A, B and C types with a diameter of 500 mm. To facilitate the application of the selected standard sections to the practical tasks, the design PM diagram and design shear forces are proposed in accordance with the strength design method and limit state design method.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.171-181
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• 2003

This study concerns the prediction of shear capacity, as governed by concrete breakout failure, concrete pryout failure and steel failure, of single anchors located close to free edge and located far from a free edge and installed in uncracked, unreinforced concrete. For this purpose, the methods to evaluate the shear capacity of the single anchors in concrete are summarized and the experimental data are compared with capacities by the two present methods: the method of ACI 349-90 and concrete capacity design (CCD) method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.172-177
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• 2004

A planetary gear trains has characteristics in compactness, power transformation ability and constant meshing. Usability is increased in applications of auto transmission and industrial gearbox. Study on optimum design of planetary gear train has been progressed on minimization of weight, miniaturization of planetary gear train and improvement of high strength. There are demands of study for the planetary gear train required long lift estimation In this wort being considered life, strength, intereference, contact ratio and aspect ratio, the optimum design algorithm is proposed to reduce the volume of planetary gear train with transferring the same amount of power. In the design of algorithm for planetary gear train, the determination of teeth number is separated to achieve simplicity and the simulated annealing method as a global optimal technique is used for optimal design method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.58-65
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• 2005

A planetary gear trains has characteristics in compactness, power transformation ability and constant meshing. Usability is increased in applications of auto transmission and industrial gearbox. Study on optimum design of planetary gear train has been progressed on miniaturization of weight, miniaturization of planetary gear train and improvement of high strength. There are demands of study f3r the planetary gear train required long life estimation. In this work being considered life, strength, interference, contact ratio and aspect ratio, the optimum design algorithm is proposed to reduce the volume of planetary gear train with transferring the same amount of power. In the design of algerian for planetary gear train, the determination of teeth number is separated to achieve simplicity and the simulated annealing method as a global optimal technique is used far optimal design method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.10
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• pp.950-955
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• 2005

For the insulation design of a high temperature superconducting(HTS) cable, three kinds of design method were proposed, which used AC and impulse withstand voltage and partial discharge inception strength. However, the designed insulation thickness by AC and impulse could not be applied to cable fabrication process due to much low electrical breakdown strength. The effect of the multi-layered insulation paper was not considered on the previous insulation design and the insulation thickness by partial discharge inception strength could be applied only. In this paper, the electrical breakdown characteristic, which considered the effect of multi-layered of LPP, was investigated to design the insulation thickness.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.479-484
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• 2000

In this study, optimal design of reinforced concrete piers under seismic load is numerically investigated. Object function is the area of the concreate-section. Design variables are the total area of reinforcement and concrete-section dimension(Circular section diameter). Constraints of the design strength of the column, longitudinal reinforcement ratio and lower and upper bounds on the design variables are imposed. The reinforcement concrete column is analysed and designed by the Ultimated Strength Design method and load combination involving dead, live, wind and seismic load is used. For numerical optimization, ADS(Garret N, Vanderplaats_ routine is used. From the result of numerical examples, the concrete-section dimension was reduced, but longitudinal reinforcement was not changed. The results show that confinement reinforcement was reduced and confinement reinforcement spacing is increased. The higher strength of reinforcement used, the more concrete-section area was reduced.