• Structural Engineering and Mechanics
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• 제5권5호
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• pp.565-576
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• 1997

The material-based homogenization design method generates arbitrary topologies of initial structural design as well as reinforcement structural design by controlling the amount of material available. However, if a small volume constraint is specified in the design of Lightweight structures, thin and slender structures are usually obtained. For these structures stability becomes one of the most important requirements. Thus, to prevent overall buckling (that is, to increase stability), the objective of the design is to maximize the buckling load of a structure. In this paper, the buckling analysis is restricted to the linear buckling behavior of a structure. The global stability requirement is defined as a stiffness constraint, and determined by solving the eigenvalue problem. The optimality conditions to update the design variables are derived based on the sequential convex approximation method and the dual method. Illustrated examples are presented to validate the feasibility of this method in the design of structures.

• 항공우주시스템공학회지
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• 제2권2호
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• pp.35-41
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• 2008

The structural stability for preliminary model of supersonic rocket which has large L/D ratio is investigated. Large L/D ratio can cause a critical problem on the structural stability by the increase of bending-moment. By using the ANSYS and the CFX codes, we inspected the structural stability for Ma=2 and angle of attack for $20^{\circ}$. The optimum number of bolts and their joints required on the rocket surface are predicted.

• International Journal of Aerospace System Engineering
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• 제8권2호
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• pp.1-3
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• 2021

This study proposed a specific preliminary structural design procedure of the main wing for a small scale WIG vehicle to meet the target weight of the system requirement. The high stiffness and strength Carbon-Epoxy material was used for lightness, and the foam sandwich type structure at the upper skin and the spar webs was adopted for improvement of structural stability. After structural design, wing joint part was designed. Through investigation on structural design result, design modification was performed. After design modification, even thought the designed wing weight was a little bit heavier than the target wing weight, the structural safety and stability of the final design feature was confirmed.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 봄 학술발표회논문집
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• pp.45-52
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• 1993

Evaluation of structural stability of aged wharf structure of pier type is of great importance for both safety and rehabilitation, Series of field dynamic experiments were performed for berthing impact and the results were used to calibrate analysis model. Through dynamic analysis for design, berthing impact safety of old wharf structure were evaluated. In this paper the procedure and results of experiments and analysis are presented.

• 한국기계가공학회지
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• 제13권1호
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• pp.39-44
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• 2014

Techniques of tool posts are developing such that variable machining is possible using only one machine for the complication of a product's shape and to reduce the machining time. In order to develop a mill turret with a variable machining function with the mounting of mill turret units on a B-axis tilting table, we determine the static/dynamic stability of the structure of the mill turret. To this end, a static structural analysis and a modal analysis were conducted. From the results of the static structural analysis, the maximum stress was found to be less than the allowable stress. By the comparing the results of the modal analysis of the excitation frequencies of the mill turret, there were no resonance regions found. Therefore, the mill turret with the B-axis tilting facility is shown to have good structural integrity.

• Design & Manufacturing
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• 제14권4호
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• pp.58-64
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• 2020

Lately, the development of the semiconductor industry has led to the miniaturization of electronic devices. Therefore, semiconductor wafers of very thin thickness that can be used in Multi-Chip Packages are required. There is active research on the backgrinding process to reduce the thickness of the wafer. The backgrinding process polishes the backside of the wafer, reducing the thickness of the wafer to tens of ㎛. The equipment that performs the backgrinding process requires ultra-precision. Currently, there is no full auto backgrinding equipment in Korea. Therefore, in this study, ultra-precision backgrinding equipment was designed. In addition, finite element analysis was conducted to verify the equipment design validity. The deflection and structural stability of the backgrinding equipment were analyzed using finite element analysis.

• 한국산업융합학회 논문집
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• 제26권6_3호
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• pp.1341-1347
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• 2023

This study proposes to ensure the seismic stability of an existing switchboard for emergency diesel generator by applying mode analysis, static analysis and dynamic analysis. First, a three dimensional model for the swithboard was made with simplification for mode analysis. Next, The mode analysis for the finite element model of the existing switchboard was performed. The 1st natural frequency below 33 Hz, the seismic safety cutoff frequency, was calculated to be 21.943 Hz. Finally, based on the seismic stability theory, the von-Mises equivalent stresses derived by structural analysis and response spectrum analysis under the normal and faulted conditions were 74.179 MPa and 49.769 MPa, respectively. These are less than specified allowable stresses. So seismic stability was confirmed.

• International Journal of Aerospace System Engineering
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• 제2권1호
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• pp.38-42
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• 2015

This work is to propose a structural design and analysis procedure for development of the low noise 1kW class small wind turbine system which will be applicable to relatively low speed region like Korea and for the domestic use. The proposed structural configuration has a sandwich composite structure with the E-glass/Epoxy face sheets and the Urethane foam core for lightness, structural stability, low manufacturing cost and easy manufacturing process. Structural analysis including load cases, stress, deformation, buckling, vibration and fatigue life was performed using the Finite Element Method, the load spectrum analysis and Miner rule. In order to evaluate the designed structure, the structural test was carried out and its test results were compared with the estimated results. Moreover Investigation on structural safety of tower was verified through structural analysis by FEM.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.490-494
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• 2008

U-Channel Bridge is effective bridge type, because its edge beam performs role of barrier and enables to reduce additional dead loads. Although it is effective to reduce additional dead loads, there is possibility of bridge collapse under impact load due to car crash. Also, edge beam must have ability to induce safe driving and prevent falling accidents. Therefore, it requires behavior analysis and property investigation through the vehicle impact crashing edge beam. This study presents method of structural analysis of U-channel bridge and investigates design specifications for the effect of the edge beam under the vehicle impact. Also, it carries out stability investigation of behavior of edge beam and slab, based on Korean Highway Bridge Design Specifications and AASHTO LRFD Bridge Design Specification.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1524-1533
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• 2021

The structural stability of a waste package is essential for containing radioactive waste for the long term in a repository. A silo-type disposal facility would require more severe verification for the structural integrity, because of radioactive waste packages staked with several tens of meters and overburdens of crushed rocks and shotcretes. In this study, structural safety was analyzed for a silo-type repository, located approximately 100 m below sea level in Gyeongju, Korea. Finite element simulation was performed to investigate the influence of the loads from the backfilling materials and waste package stacks on the mechanical stress of the disposed of wastes and containers. It was identified that the current design of the waste package and the compressive strength criterion for the solidified waste would not be enough to maintain structural stability. Therefore, an enhanced criterion for the compressive strength of the solidified waste and several reinforced structural designs for the disposal concrete container were proposed to prevent failure of the waste package based on the results of parametric studies.