• 대한기계학회논문집A
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• 제25권1호
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• pp.106-114
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• 2001

In this study, a shape optimization of stiffener was conducted to increase buckling load or failure load in each case with a different design value and a different objective function for stiffened laminated composite panel of I-type under compression loading. Regarding each of buckling load or failure load as objective function, optimum design was carried out. In respect of optimum design, the effects of relative length of web and cab of stiffener on buckling load or failure load of postbuckling were investigated.

• Journal of Mechanical Science and Technology
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• 제14권12호
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• pp.1358-1364
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• 2000

• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1211-1221
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• 2002

A shape optimization of stiffener was conducted to increase buckling load or failure load with stiffened laminated composite panel of I-type under compression loading. Design variables are cap length, web length, and/or thickness under the constraint of volume constancy. The objective function is buckling load and failure load of post-buckling based on Tsai-Hill theory using ABAQUS 5.8 for analysis and Optimizer on Broydon-Fletcher Goldfarb-Sharno Method and Augmented Lagrange Multiplier Method. The effects of relative length of a web and a cap of stiffener on buckling load and failure load of post-buckling were investigated with the results of optimum design.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.18-25
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• 2020

This study investigated the structural behaviors and safety of an electro-mechanical linear actuator and a load simulator with a plate spring. The material and dimensions of the plate spring were determined by theoretically calculating the stress and torsional angle for the rating load of the actuator. Thereafter, a flexible multibody dynamics (FMBD) analysis was conducted on the linear actuator and load simulator to confirm the performance of the load simulator and acquire the reaction forces acting on the actuator and simulator. The structural safety of the linear actuator and load simulator was evaluated via finite element analysis using the aforementioned reaction forces. Consequently, the proposed linear actuator and load simulator were determined to be structurally safe; however, the safety factors for the actuation rod and the housing on the actuator were excessively high. Therefore, the weight and cost must be reduced to improve their design parameters in the future.

• 한국건축친환경설비학회 논문집
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• 제12권6호
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• pp.606-617
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• 2018

Increased density of racks has resulted in increased use of data center cooling energy and the needs for energy efficient cooling systems has increased. In response to these needs, ASHRAE presented a performance indicator, which is Mechanical Load Component (MLC), for the purpose of evaluating systems at the design stage. However, the MLC metrics presented in the current standard can only be determined for system compliance and compared alternative systems with the system configuration completed. Therefore, there are limitations to considering MLC from the early stages of design. In this study, to extend the scope of application of MLC in the design phase, the design factors of the main equipment comprising the cooling system are classified by the MLC load component and interrelations between design factors were identified.

• Journal of Mechanical Science and Technology
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• 제18권6호
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• pp.946-954
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• 2004

A model in the form of a Bearing Load Distribution (BLD) matrix in the Multi Bearing Rotor System (MBRS) is established by a transfer matrix equation with the consideration of a bearing load, elevation and uniform load distribution. The concept of Bearing Load Sensitivity (BLS) is proposed and matrices for load and elevation sensitivity are obtained. In order to share MBRS design resources on the Internet with remote customers, the basic principle of Remote Computing (RC) based on the Internet is introduced ; the RC of the BLD and BLS is achieved by Microsoft Active Server Pages (ASP) technology.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.121-126
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• 2014

The accurate determination of induction motor efficiency depends on the estimation of the five losses of stator and rotor copper loss, iron loss, mechanical loss and stray load loss. As the mechanical and stray load losses are not calculated by electro-magnetic analysis, the values of these two losses are very important in induction motor design. In this paper, the values of mechanical loss and stray load loss are proposed through investigating testing data from commercial products of three phase induction motors under 37kW. If the values of this paper are applied to motor design, the accuracy of design and analysis can be improved. The losses of motors are obtained by using load and no-load test results following IEC 60034-2-1 standard.

• 산업기술연구
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• 제27권A호
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• pp.163-168
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• 2007

For an accurate computer simulation to motor drive systems, the target mechanical load system driven by a motor needs to be model its characteristics accurately. In general, a load system is modeled simply with system parameters such as approximated system inertia and friction. So, simulation results have some errors compared with experimental results for a real load system. RecurDyn is a mechanics simulation program for 3-dimension analysis to mechanical load systems. From this program, parameters such as a load torque, a system inertia and a viscous friction can be obtained accurately which are required to model a mechanical system. Also, this program operates together Matlab/Simulink which is used to simulate electrical motor drive systems. So, an accurate simulation for the whole system with a motor drive system and a mechanical load is possible. This paper introduces an application of RecurDyn program to an electric forklift drive system using IPMSM(Interior Permanent Magnet Synchronous Motor) and examines the feasibility of co-simulation it with Matlab/Simulink.

• 대한기계학회논문집A
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• 제30권5호
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• pp.560-567
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• 2006

The exact load measurements for the mechanical parts of a wind turbine are important step both fur the evaluation of a specific wind turbine design and for a certification process. A common method for a mechanical load measurement is using a strain gauge sensing. Two main problems ought to be answered in order for this method to be applied to the wind turbine project. These are strain gauge calibration and non-contact signal transmission from the strain gauge output to a load monitoring system. This paper suggests reliable solutions fer these two problems. A Bluetooth, a short range wireless data communication technology, is used to solve the second problem. The first one, the strain gauge calibration methodology for a load measurement in a wind turbine application, is fully explained in this paper. Various mechanical loadings for a strain gauge calibration in a wind turbine load measurement are introduced and analyzed. Initial experimental results which are obtained from a 1 kW small size wind turbine are analyzed, and the uncertainty problem in estimating mechanical loads using a calibration matrix is fully covered in this paper.

• 대한기계학회논문집A
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• 제33권9호
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• pp.949-956
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• 2009

The C(t)-integral describes amplitude of stress and strain rate field near a tip of stationary crack under transient creep condition. Thus the C(t)-integral is a key parameter for the high-temperature crack assessment. Estimation formulae for C(t)-integral of the cracked component operating under mechanical load alone have been provided for decades. However, high temperature structures usually work under combined mechanical and thermal load. And no investigation has provided quantitative estimates for the C(t)-integral under combined mechanical and thermal load. In this study, 3-dimensional finite element analyses were conducted to calculate the C(t)-integral of elastic-creep material under combined mechanical and thermal load. As a result, redistribution time for the crack under combined mechanical and thermal load is re-defined through FE analyses to quantify the C(t)-integral. Estimates of C(t)-integral using this proposed redistribution time agree well with FE analyses results.