• Tribology and Lubricants
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• v.11 no.2
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• pp.24-33
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• 1995

This paper presents the contact stress distributions between the multi-contact bodies and the total reaction forces for various types of contact geometry for multi-load slewing ring bearings. The FEM results indicate that the slope of the roller type of slewing ring bearing has slightly steeper than that of the ball type. This is because the roller type wire race bearings is stiffer than the ball type bearing. The total reaction force of ball type slewing bearing shows much higher than that of wire race slewing bearings.

• Tribology and Lubricants
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• v.5 no.2
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• pp.42-47
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• 1989

The thermal behaviour of layerd solids, typified in practice by surface coated materials, is evaluated for the specific case of a fast moving heat source. This is intended to represent the particular instance of solids in sliding contact and the consequences of friction. The finite difference method has been utilised to establish the temperature distributions at the surface and also the sub-surface region for coating materials which are either less conductive or more conductive than the substrate to which they are attached. The effects of variation in layer thickness, and also the load, speed and friction coefficient, are evaluated.

• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.921-929
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• 2014

A bivariate exponential distribution with a location parameter is proposed as a model for a two-component shared load system with a guarantee time. Some statistical properties of the proposed model are investigated. The maximum likelihood estimators and uniformly minimum variance unbiased estimators of the parameters, mean time to failure, and the reliability function of system are obtained with unknown guarantee time. Simulation studies are given to illustrate the results.

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.385-396
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• 2012

Thermal shock test methods and thermal shock parameters for ceramics were reviewed from the following viewpoints: (1) The test methods should be based on the precise estimation of both temperature and thermal stress distributions in a specimen taking into account the temperature-dependent thermo-mechanical properties; (2) The thermal shock parameters must be defined as a physical property of the materials and described as a function of temperature at the fracture point of the specimen; (3) The relation between the strength and fracture toughness of brittle ceramics under a thermal shock load must be the same as the relation under a mechanical load. In addition, appropriate thermal shock parameters should be defined by the thermal shock strength and thermal shock fracture toughness based on stress and energy criteria, respectively. A constant heat flux method is introduced as a testing technique suitable for estimating these thermal shock parameters directly from the electric power charged.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.618-623
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• 2008

Due to recent trends of the atypical plan shapes and the zoning construction in high-rise buildings, the building stability under construction is arising as an important issue for design and construction plan. To ensure the stability under construction, the differential column shortening and the lateral movements with unbalanced distributions of self-weight of structure members and the load flows before completion of member connections and lateral load resisting system should be checked by construction sequence analysis. This paper presents the scheme of zone-based construction sequence analysis, to check the stability of high-rise building under construction. This scheme is applied to the construction sequence analysis for real high-rise building under construction.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.807-812
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• 2001

The effects of casing shapes on the interaction of the impeller and volute in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuser, and casing, calculations with a multiple frame of reference method between the rotating and stationery parts of the domain are carried out. For incompressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To predict the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1772-1777
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• 2007

This paper provides plastic limit loads of pipes with constant-depth, circumferential part-through surface cracks under combined pressure and bending. A key issue is to postulate discontinuous hoop stress distributions in the net-section. Validity of the proposed limit load solutions is checked against the results from three-dimensional (3-D) finite element (FE) limit analyses using elastic-perfectly plastic material behavior.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.161-165
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• 2004

Safety and efficiency in the construction of RC structures mainly depends on optimal operation of shore-slat systems. The disasters in RC construction are mainly due to excessive load applied to falsework and premature removal of supports. Development of sufficient compressive strength of early-age connote is essential for the safety of structures during construction. Most of studies on shore-slab interaction have focused on flat slab structures. In this study, load distributions in floor slabs and supports during the construction of shear wall-type RC apartment building structures is investigated using finite element analysis.

• Structural Engineering and Mechanics
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• v.28 no.2
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• pp.189-206
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• 2008

In several design codes and specifications, simplified formulae and charts are given for determining the effective lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of braced frames is developed. The procedure utilises a fictitious load analysis of frames and yields errors less than 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range.

• Structural Engineering and Mechanics
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• v.19 no.1
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• pp.55-71
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• 2005

In several design codes and specifications, simplified formulae and diagrams are given for determining the buckling lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of multi-storey frames is developed. The procedure utilises lateral load analysis of frames and yields errors in the order of 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range and on the safe side.