• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2634-2645
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• 1993

Dome structures of pressure vessels subjected to internal pressure are usually analyzed by linear elastic theory assuming small deformation. Geometric and material nonlinear behaviors appear in actual dome structures because of large deformation and loads exceeding yield strength. In this paper, linear and nonlinear analyses were performed for various hemispherical and torispherical domes to check the effects of geometric and material nonliearity on the stress and displacement by the finite element method. The effect of the geometric nonlinearity decreased the stress levels a lot for very thin general torispherical domes, which enables more realistic and effective design. The material nonlinear effects are negligible for hemispherical and optimum torispherical domes, and those are large for most of the general torispherical domes.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.04a
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• pp.295-302
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• 1999

This paper is the experimental and analytic of reinforced concrete hemisphere dome under vertical load. It is described that when the reinforced concrete hemispherical dome supported on cylindrical wall is loaded vertically, how the opening part of dome will behave mechanically The experimental and analytic model is a Hemispherical dome with opening and the meridian angle of opening is 76$^{\circ}$at the center of sphere under concentrated load around the opening, but this is reinforced by a ring is sufficient stiffness. The diagrams of crack development are represented to understand the behavior of the reinforced concrete hemispherical dome. The method of crack analysis will be applied the rigid element spring model. The rigid element spring model is a new discrete element analysis, each divided element is assumed by rigid elements without deformation which is interconnected with elasto-plastic spring system.

• Journal of Korean Association for Spatial Structures
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• v.16 no.1
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• pp.53-64
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• 2016

Solar power is being spotlighted recently as a new energy source due to environmental problems and applications of solar power to curved structures are increasing. Solar panels installed on curved surfaces have different efficiencies depending on its position and the efficient positioning of solar panels plays a critical role in the design of solar power generation systems. In this study, the changing characteristics of solar irradiance were analyzed for hemispherical dome with a large curvature and the positioning of solar panels that can efficiently utilize solar energy was investigated. With an icosahedron-based hemispherical dome consisting of triangular elements as target model, a program for calculating solar irradiance using a normal vector of the solar module on each face was developed. Furthermore, the change of solar irradiance according to the sun's path was analyzed by time and season, and its effects on shades were also examined. From the analysis results, the effective positioning could be determined on the basis of the efficiency of the solar panels installed on the dome surfaces on solar irradiance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.72-75
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• 1997

In this paper, the forming limits of laser welded blank sheets are introduced, obtained from a tensile test and a hemispherical dome punch test. Especially, the forming limit diagram(FLD) on the heat affected zone with a width 2.54mm is emphasized. Also, the experimental experiences in finding specific strain conditions are discussed.

• Journal of Korean Association for Spatial Structures
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• v.15 no.2
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• pp.51-59
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• 2015

In this study, a shape design and an analysis considering structural stability were investigated to develop an icosahedron-based hemispherical modular dome. To design this modular dome, a program that can perform icosahedron shape modeling, modularization of joint connection members, and the analysis of structural stability was developed. Furthermore, based on the adopted numerical model, the eigen buckling mode, unstable behavior characteristics according to load vector, and the critical buckling load of the modular dome under uniformly distributed load and concentrated load were analyzed, and the resistance capacities of the structure according to different load vectors were compared. The analysis results for the modular dome suggest that the developed program can perform joint modeling for shape design as well as modular member design, and adequately expressed the nonlinear behaviors of structured according to load conditions. The critical buckling load results also correctly reflected the characteristics of the load conditions. The uniformly distributed load was more advantageous to the structural stability than concentrated load.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.379-388
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• 2000

This study aims to examine the influence of experimental and numerical factors on the results of the test and finite element simulation to evaluate the formability of sheet metals. The stretch-forming test with a hemispherical punch is carried out to obtain the limiting dome height (LDH) and forming limit diagram (FLD) for several kinds of aluminium and steel sheet. The results of the LDH and FLD tests are analysed to find any correlation with the uniaxial tensile properties. It proves that the size of the prescribed grid has great influence on the measured value of strain. The finite element analysis of the punch stretching process is also carried out and the result is compared with the experimental data. The influence of the numerical parameters such as friction coefficient, element size and anisotropy model on the simulation results tms out to be very considerable.

• Transactions of Materials Processing
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• v.9 no.1
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• pp.3-9
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• 2000

The new FLD of the laser welded blank, which includes FLCs of welded zone and base metals, is introduced. For the forming limits of welded zone, the hemispherical dome punch tests were performed with various widths of asymmetric specimen. The FLC0 as well as the dome height at fracture associated with various specimen widths in the same and different thickness combinations were found to see the formability depending on thickness combinations. In order to show the application of the new FLD, the measured strains of squared cup drawing and simulated strains of door inner panel stamping were compared with those of FLCs. The successful prediction of fracture in the applications reveals that the forming limits of welded zone and base metals should be separately found for more accurate evaluation of the formability and workability of the laser welded blank.

• Journal of architectural history
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• v.2 no.2 s.4
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• pp.89-106
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• 1993

Wherever Buddhism has flourished, there were stupas in the form of monuments which have their origin in the tumulm of prehistoric times. After the death of Buddha, his body was cremated following the Indian funeral custom. His ashes, which long reserved for the remains of nobles and holymen, were enshrined under such artificial hills of earth and brick. The Stupa was in origin a simple burial-mound. The form of the burial-mound was a symbolical or magic reconstruction of the imagined shape of the sky, like a dome covering the earth. The domical form of the earliest tumuli may have been concious replicas of the shape of the Vedic hut. There are relationships which may have originally existed between the stupa and West Asiatic monuments. Buddhist Stupa originally cosisted of an almost hemispherical tumulus(anda) and an altar-like structure (harmika) on its top, surmounted by one or several superimposed honorific umbrellas (hti, catta). This hemispherical form is associated with centralisation, lunar worship, mother earth, and Siva. Anda means a symbol of latent creative power, the harmika symbolizes the sanctuary enthroned aboved the world. The honorific umbrella, as an abstract imitation of the shade-giving tree is one of the chief solar symbols and that of enlightenment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1132-1137
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• 1993

A simple simulative test was developed to evaluate stamping formability in plane strain stretching mode. The stamping formability was evaluated by limit punch height(LPH) in plane strain punch stretching test(PSST) compared to limit dome height(LDH) in hemispherical punch stretching test. PSST shows stable plane strain condition and good reproducibility with minimum scatter. Moreover LPH-value in PSST well ranks the stamping formability of various material and correlates with press performance.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03a
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• pp.14-17
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• 1999

The finite element formulation is developed for predicting strain distributions and weld line movements in the forming processes of laser welded blank. The welded zone(WZ) is modelled with several narrow finite elements whose material characteristics are analytically obtained from those of base metals based on the tensile tests. In order to show the reliability and effectiveness of weld element the forming process of hemispherical dome stretching and auto-body door inner panel stamping are simulated FEM predictions show good agreements with experimental observations.