• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.217-222
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• 2000

An iterative numerical computational algorithm is presented to design a plate or shell element subjected to membrance and flexural forces. Based on equilibrium consideration, equation for capacity of top and bottom reinforcements in two orthogonal directions have been derived. The amount of reinforcement is determined locally, I. e., for each integration point, from the equilibrium between applied and internal forces. Three cases of design are performed for slab element (used by Marti(1987)) and shell element (used by Kirscher and Collins(1986), by Polak and Vecchio(1993)) to verify the adequacy of the present design method for reinforced concrete shells. Based on nonlinear analyses performed, the analytically calculated ultimate load exceeded the design ultimate load. This shows the adequacy of the design method present in this study at least for slab and shell element case studied. To generalize the conclusion more design-analyses should be performed with different shell configurations.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.405-411
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• 1998

An iterative numerical computational algorithm is presented to design a plate of shell element subjected to membrane and flexural forces. Based on equilibrium consideration, equations for capacities of top and bottom reinforcements in two orthogonal directions have been derived. The amount of reinforcement is determined locally, i. e., for each sampling point, from the equilibrium between applied and internal forces. One case of design is performed for a hyperbolic paraboloid saddle shell (originally used by Lin and Scordelis) to check the design strength against a consistent design load, therefore, to verify the adequacy of design practice for reinforced concrete shells. Based on nonlinear analyses performed, the analytically calculated ultimate load exceeded the design ultimate load from 14-43% for an analysis with relatively low to high tension stiffening, ${\gamma}$ =5~20 cases. For these cases, the design method gives a lower bound on the ultimate load with respect to Lower bound theorem. This shows the adequacy of the current practice at least for this saddle shell case studied. To generalize the conclusion many more designs-analyses are performed with different shell configurations.

• Computers and Concrete
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• v.31 no.3
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• pp.223-239
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• 2023

Geometric nonlinear performance simulation and analysis of complex modern buildings and industrial products require high-performance shell elements. Balancing multiple aspects of performance in the one geometric nonlinear analysis element remains challenging. We present a new shell element, flat shell DKMGQ-CR (Co-rotational Discrete Kirchhoff-Mindlin Generalized Conforming Quadrilateral), for linear and geometric nonlinear analysis of both thick and thin shells. The DKMGQ-CR shell element was developed by combining the advantages of high-performance membrane and plate elements in a unified coordinate system and introducing the co-rotational formulation to adapt to large deformation analysis. The effectiveness of linear and geometric nonlinear analysis by DKMGQ-CR is verified through the tests of several classical numerical benchmarks. The computational results show that the proposed new element adapts to mesh distortion and effectively alleviates shear and membrane locking problems in linear and geometric nonlinear analysis. Furthermore, the DKMGQ-CR demonstrates high performance in analyzing thick and thin shells. The proposed element DKMGQ-CR is expected to provide an accurate, efficient, and convenient tool for the geometric nonlinear analysis of shells.

• Steel and Composite Structures
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• v.17 no.6
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• pp.867-890
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• 2014

This paper deals with the geometric nonlinear bending analysis of laminated composite stiffened plates subjected to uniform transverse loading. The eight-noded degenerated shell element and three-noded degenerated curved beam element with five degrees of freedom per node are adopted in the present analysis to model the plate and stiffeners respectively. The Green-Lagrange strain displacement relationship is adopted and the total Lagrangian approach is taken in the formulation. The convergence study of the present formulation is carried out first and the results are compared with the results published in the literature. The stiffener element is reformulated taking the torsional rigidity in an efficient manner. The effects of lamination angle, depth of stiffener and number of layers, on the bending response of the composite stiffened plates are considered and the results are discussed.

• Korean Institute of Interior Design Journal
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• no.13
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• pp.203-215
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• 1997

This Study typed the roof-design in analysis of structural design of the glulam architecture, developed worldwidely, nowaday. For this, it is studied the characters of glulam as the history of glulam architectures, manufacture of glulam, shapes and section of glulam, fireproof and combution of glulam. And it is studied roof-design according to structural type of glulam roof-structure. Conclusively, types of glulam roof design typied as 1)the Simple Beam str., 2)the Multi-Joints continous Beam str. 3)the Hinge str. 4)the Rahmen str. 5)the Archi str. 6)the Grid str. 7)etc str. (Folded-plate str., Radial str., Cylinder Shell str., Ring Dome str., Geodesic Dome str., Conic Coloid Shell str., H.P Shell str. Cantilever Shell str.)

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.103-118
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• 2018

When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper-Symonds model and Johnson-Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

• Journal of the Korea Safety Management & Science
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• v.10 no.2
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• pp.85-94
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• 2008

The object of this study is to investigate the penetration characteristics according to the change of stacking sequences and curvature radius in the composite laminated shell. They are staked to [02/902]S and [0/902/0]s, their interlaminar number are two and four. We are manufactured to composite laminated shells with various curvature radius. Curvature radius of composite shell is 100, 150, 200mm and ${\infty}$(it's meaning flat-plate). In general, kinetic energy after impact-kinetic energy before impact increased linearly in all specimens. Absorbed energy increased linearly as the curvature increased, and absorbed energy of [02/902]S specimen, which is small interlaminar number, was higher than [0/902/0]s specimen.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.6
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• pp.933-941
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• 1997

In the analysis of thin elastic structures such as plate and shell-like structures, classical lower-order theories like Kirchhoff and Reissner-Mindin theories are insufficient to describe the behavior of such structures in the region where the state of stresses is complex. On the other hand, the fully three dimensional theory of linear elasticity can provide desired analysis accuracy, but requires expensive computational implementation compared to the classical theories. This paper is concerned with the development of hierarchical models for elastic structures which can be used for hierarchical modeling for the analysis of such structures. Derivation and limit model analysis (when the thickness of structures tends to zero) of hierarchical models are presented together with a introduction of modeling error estimation. Also, numerical results supporting theoretical results are given.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.66-74
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• 2019

In the field of shipbuilding design, the use of 3D CAD is becoming commonplace, and most of the large shipyards are conducting 3D design. However at the production site, workers are still working on 2D drawings rather than 3D models. This tendency is even worse in small-scale shipyards and block manufacturing shops. Particularly, in a manufacturing shop that is engaged in the outsourcing of blocks, it may not be possible to provide 3D model. However, the demand for 3D models in the production field is steadily increasing. Therefore, it would be helpful if 3D model could be generated from a 2D drawing. In this paper, we propose a method to extract template and unfolded surface shape information from shell template offset drawing using computer vision technology. Also a 3D surface model was reconstructed and visualized from the extracted information. The result of this study is thought to be helpful in the work environment where 3D model information can not be obtained.

• Advances in materials Research
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• v.12 no.2
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• pp.83-100
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• 2023

In this paper, sandwich plate, constructed with orthotropic and isotropic composite materials, is analyzed to obtain the static and harmonic behavior. The analysis is done by using ANSYS APDL FEM tool. A solid-shell 190 and an 8-node solid 185 elements are employed for face and core material respectively to analyze the plate. Results was attained by using Reissner-Mindlin theory. Effect of increasing thickness ratio of face sheet to depth of the plate is presented on static, vibration and harmonic response on the sheet and the results are discussed briefly. Published work in open domain was used to validate the results and observed excellent agreement. It can be stated that proposed model presents results with remarkable accuracy. Results are obtained to reduce the weight of the plate and minimizing the vibration amplitudes.