• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.309-316
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• 2004

A probabilistic structural integrity assessment is performed for a reactor pressure vessel under PTS(Pressurized Thermal Shock). A semi-elliptical finite axial crack is assumed to he in the beltline region(either base metal or weld meta)1 of the reactor vessel inside surface. The selected random variables are initial crack depth, neutron fluence on the vessel inside surface, copper, nickel, and phosphorus content of the vessel material, and RT/sub NDT/. The probabilities of crack initiation or vessel failure where the crack is propagated through vessel wall are calculated. The probabilities obtained with random crack size are compared to these obtained with deterministic us. Since the failure function cannot to explicitly by selected by selected random variables, Monte Carlo Simulation is applied to perform probabilistic analysis The influence of the amount of neutron fluence is also examined to assess the structural reliability for vessel life time.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.367-375
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• 2018

The present paper considers the contact between energy-saving device of ice-class vessel and ice block. The main objective of this study is to clarify the tendency of the ice impact force and the structural response as well as interaction effects of them. The contact analysis is performed by using LS-DYNA finite element code. The main collision scenario is based on Finnish-Swedish ice class rules and a stern duct model is used as an energy-saving device. For the contact force, two modelling approaches are adopted. One is dynamic indentation model of ice block based on the pressure-area curve. The other is numerical material modelling by LS-DYNA. The authors investigated the sensitivity of the structural response against the ice contact pressure, the interaction effect between structure and ice block, and the influence of eccentric collision. The results of these simulations are presented and discussed with respect to structural safety.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.2
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• pp.44-52
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• 2001

A modeling program was developed in Part I which represents the 3-D geometry, produces bill of material, automatically draws drawings and produces input data for structural analysis of Very High-rise Steel Artificial Reefs(VEHSAR). Model tests were carried out to measure drag forces acted on VEHSAR in the Ocean Engineering Wide Tank, the University of Ulsan and structural analyses were made to simulate structural behaviors of VEHSAR. The integrated package system is suggested to design VEHSAR with different geometries.

• Journal of KIBIM
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• v.3 no.3
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• pp.19-28
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• 2013

In Korea highway bridges, most piers are the type of one-column or multi-column ones. So, in this study, under an environment applying BIM so fast, to activate researches on two-column piers subjected to bidirectional seismic loading, a 3D parametric modeling method was selected when the model of two-column piers and one-column piers were formed. Also, interface module between input data in structural analysis and 3D model of RC pier was developed. The module can create the input data for non-linear structural analysis like material, geometric properties and additional coefficients.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.70-76
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• 2013

This study investigates structural durability through the analyses of stress, fatigue life and vibration damage at bike carrier basket. As model 2 has less stress and deformation than model 1 on static structural analysis, model 2 becomes more durable than model 1. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. The amplitude deformations become highest at maximum response frequency of 2400Hz in cases of models 1 and 2. As the values of maximum equivalent stresses become within the allowable material stresses at two holes at the upper parts on models 1 and 2, these models become safe. The structural result of this study can be effectively utilized with the design of bike carrier basket by investigating prevention and durability against fatigue or vibration damage.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.1
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• pp.144-149
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• 2007

Behaviour of a thread joint of a rocket motor case show complex structural characteristics. Pre-torque must be applied to the threads to prevent the loosening of the interface from the additional pressure load. During the pressurization of the rocket motor case, the jointing face may be opened if the pre-torque were not set properly or the structure may be failed if the local concentrated stress exceeds the strength of the material. In this paper, the structural behaviour of a thread joint of a rocket motor case were analyzed by the finite element method and the results were compared to the experimental ones. A method to set a pre-torque for a thread joint were proposed to ensure the structural safety.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.319-326
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• 1998

Structural intensity of plates experiencing bending vibration is analytically evaluated using the modal analysis based on the assumed mode method. In the analysis, material internal loss and localized damping are considered. The power obtained by structural intensity integration over the circle containing the excitation source is compared with the power injected into plates to verify the accuracy of the presented method and; to evaluate the convergence of mode superposition. The intensity integration is carried out varying the circle radius and the integral step to investigate their effects in case of the power estimation using structural intensities. In addition, the dominant component among internal forces in the energy transfer by the bending vibration of a stiffened plate is investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.155-160
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• 2003

For the weight reduction of vehicle body up to 20∼30% compared to the conventional monocoque steel body·.in-white, most automotive manufacturers have attempted to develop the aluminum intensive body-in-white using an aluminum space frame. In this paper, the crush tests and simulations for the aluminum extrusions filled with the structural from are performed to evaluate the collapse characteristics of that light weighted material. From these studies. the effectiveness of structural for is evaluated in improving automotive crashworthiness. In order to improve the improve energy absorption capability of the aluminum space frame body, safety design modifications are performed and analyzed based on the suggested collapse initiator concepts and on the application of the aluminum extrusions filled with structural foam. The effectiveness of these design concepts on the frontal and side impact characteristics of the aluminum intensive vehicle structure is investigated and summarized.

• Structural Engineering and Mechanics
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• v.52 no.6
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• pp.1121-1134
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• 2014

Structural design is usually an optimization process. Numerous parameters such as the member shapes and sizes, the elasticity modulus of material, the locations of nodes and the support constraints can be selected as design variables. These variables are progressively revised in order to obtain a satisfactory structure. Each modification requires a fresh analysis for the displacements and stresses, and reanalysis can be employed to reduce the computational cost. This paper is focused on static reanalysis problem with modification of deleting some supports. An efficient reanalysis method is proposed. The method makes full use of the initial information and preserves the ease of implementation. Numerical examples show that the calculated results of the proposed method are the identical as those of the direct analysis, while the computational time is remarkably reduced.

• Earthquakes and Structures
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• v.6 no.1
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• pp.19-43
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• 2014

A risk assessment framework for evaluating building structures is implemented in this study. This framework allows considering sources of uncertainty both on structural capacity and seismic demand. In particular randomness on seismic load, incident angle, material properties, floor mass and structural damping are considered; in addition the choice of fibre modelling versus plastic hinge model is also considered as a source of uncertainty. The main objective of this work is to study the contribution of these sources of uncertainty on the fragilities of steel and steel-reinforced concrete composite 3D building structures. The fragility curves are expressed in the form of a two-parameter lognormal distribution where vertical statistics in conjunction with metaheuristic optimization are implemented for calculating the two parameters.