• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.789-796
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• 2012

Radiated noise analysis from a ship structure is a challenging topic owing to difficulties in the accurate calculation of the fluid-structure interaction as well as owing to a massive degree of freedom of the problem. To reduce the severity of the problem, a new fluid-structure interaction formulation is proposed in this paper. The complex frequency-dependent added mass and damping matrices are calculated using the high-order Burton-Miller boundary integral equation formulation to obtain accurate values over all frequency bands. The calculated fluid-structure interaction effects are added to the structural matrices calculated by commercial finite element software, MSC/NASTRAN. Then, the impedance and underwater radiation noise due to an excitation of structure are calculated. The present formulation is applied to a ship to calculate the underwater radiated noise.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.59-67
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• 2009

Computer Aided Engineering(CAE) technology as well as Design(CAD) and Manufacturing(CAM) have been widely adopted in the aerospace industry in order to develop the structure of airplanes, satellites and launch vehicles. Among them, CAE softwares based on finite element methods such as NASTRAN, ABAQUS and ANSYS have gained many engineers' interest in various industries such as automobiles, civils, aircraft and spacecraft. The softwares usually consist of several modules: Static, Dynamic, Vibration, Impact etc. that make analysis specific to meet the design goals of the structure systems. Recent enhancement in the computer hardwares and numerical algorithms enables us to perform complex analysis like multi-physics, optimum design. Also, they make it possible to deal with a large scale problem easily. This paper reviews structural analysis softwares in aerospace industry and gives a summary on its recent development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.38-45
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• 2004

In this paper, a parallel visualization algorithm is proposed for efficient visualization of the massive data generated from large-scale parallel finite element analysis through investigating the characteristics of parallel rendering methods. The proposed parallel visualization algorithm is designed to be highly compatible with the characteristics of domain-wise computation in parallel finite element analysis by using the sort-last-sparse approach. In the proposed algorithm, the binary tree communication pattern is utilized to reduce the network communication time in image composition routine. Several benchmarking tests are carried out by using the developed in-house software, and the performance of the proposed algorithm is investigated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.5
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• pp.309-316
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• 2022

This study proposes a finite element analysis method that can analyze the vibration of a beam by considering the inertia effect of moving masses in a vertical direction. The proposed method is effective when a precise interaction analysis is not required. The inertial effects of the moving masses are included in the equation of motion, and the interaction forces between the masses and the beam are considered only as external loads. Time domain analyses were performed using Abaqus, a general-purpose finite element analysis software, and an implementation method using multi-point constraints wais presented to link the displacements of the beam element nodes and moving rigid masses. The proposed method was verified by comparing its solution with that obtained using an existing analytical method, and the analysis results for continuous beam vibrations under dynamic gait loadings were used to examine the mass effect of pedestrians.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.718-725
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• 2017

A liquid storage tank is one of the most important structures in industrial complexes dealing with chemicals, and its structural damage due to an earthquake may cause a disastrous event such as the leakage of hazardous materials, fire, and explosion. It is thus essential to assess the seismic fragility of liquid storage tanks and prepare for seismic events in advance. When a liquid storage tank is oscillated by a seismic load, the hydrodynamic pressure caused by the liquid-structure interaction increases the stress and causes structural damage to the tank. Meanwhile, the seismic fragility of the structure can be estimated by considering the various sources of uncertainty and calculating the failure probabilities in a given limiting state. To accurately evaluate the seismic fragility of liquid storage tanks, a sophisticated finite element analysis is required during their reliability analysis. Therefore, in this study, FERUM-ABAQUS, a recently-developed computational platform integrated with commercial finite element and reliability analysis software packages, is introduced to perform the finite element reliability analysis and calculate the failure probability of a liquid storage tank subjected to a seismic load. FERUM-ABAUS allows for automatic data exchange between these two software packages and for the efficient seismic fragility assessment of a structure. Using this computational platform, the seismic fragility curve of a liquid storage tank is successfully obtained.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.487-499
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• 2009

The postprocessing technology has been advanced diversely to accommodate the tendency of increasingly refined and complicated practices of finite element modeling in pace with enhanced capabilities of computers and improved algorithm of equation solvers. As a result of such progresses in both hardware and software, it became practically meaningful to inspect and analyze the elasto-plastic behavior using the intermediate results from the increasing number of incremental and iterative processes. This paper is concerned about the new methods of postprocessing with computer graphic visualization of elasto-plastic behavior on the basis of the theoretically reorganized analysis results. This paper proposes a new method of rendering the plastic zone, and new approaches of analyzing and interpreting the elasto-plastic behavior using the graphical information visualized in the form of the yield surface and the stress path, or in the form of the Mohr circles and the failure envelope.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.2
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• pp.81-93
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• 2020

The fatigue characteristics of glass fiber reinforced plastic (GFRP) composites were studied under repeated loads using the finite element method (FEM). To realize the material characteristics of GFRP composites, Digimat, a mean-field homogenization tool, was employed. Additionally, the micro-structures and material models of GFRP composites were defined with it to predict the fatigue behavior of composites more realistically. Specifically, the fatigue characteristics of polybutylene terephthalate with short fiber fractions of 30wt% were investigated with respect to fiber orientation, stress ratio, and thickness. The injection analysis was conducted using Moldflow software to obtain the information on fiber orientations. It was mapped over FEM concerned with fatigue specimens. LS-DYNA, a typical finite element commercial software, was used in the coupled analysis of Digimat to calculate the stress amplitude of composites. FEMFAT software consisting of various numerical material models was used to predict the fatigue life. The results of coupled analysis of linear and nonlinear material models of Digimat were analyzed to identify the fatigue characteristics of GFRP composites using FEMFAT. Neuber's rule was applied to the linear material model to analyze the fatigue behavior in LCF regimen. Additionally, to evaluate the morphological and mechanical structure of GFRP composites, the coupled and fatigue analysis were conducted in terms of thickness.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.3
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• pp.90-99
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• 1993

As the finite element method has become a considerable and effective design tool in ship structural analysis, modeling of three dimensional finite element mesh is more necessary than before. However, the unique style and complexity of a ship usually make the modeling be hard and costly. Although most pre-processor of FEM software and geometric modeler provides modeling function, the capability is quite limited for complicated structure. In order to perform FEM modeling quickly, it is necessary to extract, rearrange, and formalize data from ship design database for partially automatic mesh generation. In this paper, the process of designing relational data tables from design data is shown as a part of analysis automation with the application of engineering database concept.

• Journal of Energy Engineering
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• v.27 no.4
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• pp.13-19
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• 2018

In this study, the lightweight design of butterfly valve disc component for power plant based on topology optimization was performed. Here, commercial finite element (FE) analysis software was used. The external shape of the basic disc model was not deformed, and the internal element density was removed to make it lightweight. Optimal design was performed each other after the disc plate and two brackets attached on the surface of the disc were separated. Once the optimal shapes were selected, they were assembled to build up the 3-D lightweight valve disc model. After applying pressure to this model, FE analysis was performed to confirm the structural safety.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.947-953
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• 2019

The purpose of this study was to manufacture a wrist brace using a computerized tomography system, clinical design software (MediACE 3D Program), and 3D printer. After acquiring the Dicom file of the upper limb with a computed tomography, the wrist brace was designed using the MediACE 3D Program to create a "stereolithography" file. The designed wrist brace was printed using a 3D printer. To verify the effectiveness of wrist assistive device manufactured by 3D printing technology, the stress distribution of the pressure and orthosis applied to bone and skin is represented by finite element analysis. It is expected that the wrist brace can be manufactured by reinforcing the part where the damage caused by pressure and breakage of the brace frequently occurs with the result of finite element analysis when producing the wrist brace.