• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.195-204
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• 2000

The finite element analysis (FEA) is widely used in modern structural dynamics because the performance of structure can be predicted in early stage. However, due to the difficulty in determination of various uncertain parameters, it is not easy to obtain a reliable finite element model. To overcome these difficulties, a updating program of FE model is developed by consisting of pretest, correlation and update. In correlation, it calculates modal assurance criteria, cross orthogonality, mixed orthogonality and coordinate modal assurance criteria. For the model updating, the continuum sensitivity analysis and design optimization tool(DOT) are used. The SENSUP program is developed for model updating giving physical parameter sensitivity. The developed program is applied to practical examples such as the BLDC spindle motor of HDD, and upper housing of induction motor. And the sensor placement for the square plate is compared using several methods.

• Transactions of Materials Processing
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• v.15 no.3 s.84
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• pp.206-212
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• 2006

Design programs of tube-sheet for heat exchanger based on the related engineering society codes have been widely used. But it is not easy fer beginners to use the design programs. So we need to develop an easy program for design of tube-sheet for heat exchanger. This paper describes a developed design-program of tube-sheet fur heat exchanger. The developed program was coded on boiler theory and pressure vessel codes, provided by TEMA(Tubular Exchanger Manufactures Association) and ASME(American Society of Mechanical Engineers). Visual Basic, which is convenient for beginners to deal with, was used in the programming. Also a finite element analysis of tube-sheet for heat exchanger was carried to verify this developed program by using a commercial software, ANSYS. In the finite element analysis, tube and tube-sheet of heat exchanger were substituted by solid plate having equivalent properties for convenience of calculation. The thickness of tube-sheet obtained by the developed design-program was in good agreement with that of tube-sheet by FEA.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.154-159
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• 1998

In this paper, BLDC spindle motor is designed using CAE/CAT to reduce structural vibration. Motor is modeled and analyzed using a finite element analysis (FEA) program and correlated to the results of modal test. Design sensitivity analysis (DSA) of frequency is carried out and validated by the modal test of modified motor manufactured. This study shows that simulation-based design can improve quality with reduced development time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.290-301
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• 2013

The docking analysis of a global ship structure is requested to evaluate its structural safety against the reaction forces at supports during docking works inside a dry dock. That problem becomes more important recently as the size of ships is getting larger and larger. The docking supports are appropriately arranged in a dock to avoid their excessive reaction forces which primarily cause the structural damages in docking a ship and, up to now, the structural safety has been assessed against the support arrangement by the finite element analysis (FEA) of a global ship structure. However, it is complicated to establish the finite element model of the ship in the current structural design environment of a shipyard and it takes over a month to finish the work. This paper investigates a simple and fast approach to carry out a ship docking analysis by a simplified grillage model and to assign the docking supports position on the model. The grillage analysis was considered from the motivation that only the reaction forces at supports are sufficient to assess their arrangement. Since the simplified grillage model of the ship cannot guarantee its accuracy quantitatively, modeling strategies are proposed to improve the accuracy. In this paper, comparisons between the proposed approach and three-dimensional FEA for typical types of ships show that the results from the present grillage model have reasonably good agreement with the FEA model. Finally, an integrated program developed for docking supports planning and its evaluation by the proposed approach is briefly described.

• Journal of Korean Society of Steel Construction
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• v.23 no.3
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• pp.305-316
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• 2011

As the building structures are higher and bigger, the high-performance steels of high strength, toughness, and low yield ratio had been required and developed. In this paper the behavior of the moment connection with bolted web and high strength steel was studied by using the finite-element analysis computer program of ABAQUS. The analysis model is based on the test results and the same cyclic load history was applied at the FE(Finite Element) model until it failed in the test. Through the FEA, several indicators hardly measured from the test were acquired. These indicators related to stress and strain were selected from three plastic rotation stages: 0.003 rad, 0.03 rad, and final failure rotation. Specifically, at the final failure stage, the strain indicators producing the full plastic behavior were suggested as a mechanical property for steel.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.4
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• pp.35-41
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• 2001

In this paper, several methods to predict the solder joint shape are studied. Although there are various methods to predict the solder joint shape, such as truncated sphere method. force-balanced analytical solution, and energy-based methods like surface evolver developed by Ken Brakke, we calculate solder joint shape of $\mu$BGA by two solder joint shape prediction methods(truncated sphere method and surfaceevolver) and then compare results of each method. The results indicate that two methods can accurately predict the solder Joint shape in an accurate range. After that, we calculate reliability solder joint shape under thermal cycle test by FEA program ANSYS(version 5.62). As a result, it could be found that optimal solder joint shape calculated by solder joint prediction method has best reliability in thermal cycle test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.20-27
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• 2021

The present study presents a nonlinear finite element analysis (FEA) approach using the general program of Abaqus to evaluate the seismic response of unreinforced masonry walls strengthened with the steel bar truss system developed in the previous investigation. For finite element models of masonry walls, the concrete damaged plasticity (CDP) and meso-scale methods were considered on the basis of the stress-strain relationships under compression and tension and shear friction-slip relationship of masonry prisms proposed by Yang et al. in order to formulate the interface characteristics between brick elements and mortars. The predictions obtained from the FEA approach were compared with test results under different design parameters; as a result, a good agreement could be observed with respect to the crack propagation, failure mode, rocking strength, peak strength, and lateral load-displacement relationship of masonry walls. Thus, it can be stated that the proposed FEA approach shows a good potential for designing the seismic strengthening of masonry walls.

• Journal of Electrical Engineering and Technology
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• v.3 no.1
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• pp.88-93
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• 2008

The electromagnetic parameters of a permanent magnet synchronous motor (PMSM) such as the open load permanent magnet flux, d axis reactance $X_d$, and q axis reactance $X_q$, are most essential to the performance analysis and optimization design of the motor. Based on the numerical analysis of the 3D electromagnetic field, the three electromagnetic parameters of permanent magnet synchronous motors with U form interior rotor structures are calculated by FEA. The rules of the leakage coefficient and reactance parameters changing with the air gap length, permanent magnet magnetism length, and isolation magnetic bridge dimensions in the rotor are given. The calculated values agree well with the measured values. The FEA results are integrated with the self compiled electromagnetic design program to optimize the prototype motor. The tested performances of the prototype motor prove that the method is suitable for the optimization of motor structure.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.179-184
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• 2004

Each year, new technological advancements for repair-purpose are being introduced to overlay the old deterioration of RC bridge deck at highway by latex-modified concrete. The days may come when this old problem will be successfully resolved. While the experimental works and researches are very active at both laboratory and field, only a few theoretical studies were performed on interfacial problems, especially on stress distribution and concentration of RC beam overlayed by latex-modified concrete. The repaired and strengthened structures would induce a premature failure due to the stress concentration at the adhesive layer of different material before the design expected failure. This paper investigated and proposed an analytical model for predicting interfacial shear and normal stresses of RC beam repair-purpose overlayed by latex-modified concrete. This would be used for predicting interfacial stresses and preventing premature failure at interfaces. This study modified Smith-Teng method for applying to cementitious repairing material, which was based on a direct governing equation and linear-elastic approach for interfacial normal and shear stresses. The proposed theoretical model was verified using commercial FEA program, LUSAS, in terms of interfacial stresses predicted by the proposed model and calculated by LUSAS.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1840-1848
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• 2003

This paper presents the structural analysis and optimum design of a vertical micro-gyroscope with decoupled 2 degrees of freedom (DOF), driven by electrostatic force. Simplified beam models were presented to derive the structural stiffness of the driving spring of the U shape and the sensing spring of I shape. A finite element analysis (FEA) was performed to validate each derivation. A total mass and a polar mass moment of inertia were also obtained and used in calculating the resonance frequency at each mode of the 2 DOF. The resonance frequencies of the total system were calculated using the proposed models and it has been found that they were in excellent agreement with those of the FEA. Finally, the developed analysis program was then linked to an optimum design module, and an optimum design of the micro-gyroscope was successfully performed.