• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.25-29
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• 2017

This paper presents a unique pressure sensor design for environmental applications. The design uses a new geometry for a multi bossed beam-membrane structure with a SOI (silicon-on-insulator) substrate and a mechanical transducer. The Intellisuite MEMS CAD design tool was used to build and analyze the structure with FEM (finite element modeling). The working principle of the multi bossed beam structure is explained. FEM calculations show that a sensing diaphragm with Mises stress can provide superior linear response compared to a stress-free diaphragm. These simulation results are validated by comparing the estimated deflection response. The results show that, the sensitivity is enhanced by using both the novel geometry and the SOI substrate.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1665-1674
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• 1995

An optimum design has been performed to maximize specific energy (SED) of composite flywheel rotor for energy storage system. The flywheel rotor is assumed to be an axisymmetric thick laminated shell with a plane strain state for structural analysis. For the structural analysis the centrifugal force is considered and the stiffness matrix equation was derived for each ring considering the interferences between the rings. The global stiffness matrix was derived by integrating the local stiffness matrix satisfying the conditions of force and displacement compatibilities. Displacements are then calculated from the global stiffness matrix and the stresses in each ring are also calculated. 3-D intra-laminar quadratic Tsai-Wu criterion is then used for the strength analysis. An optimum procedure is also developed to find the optimal interferences and lay up angle to maximize SED using the sensitivity analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.7 s.238
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• pp.955-963
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• 2005

This research investigates dynamic characteristics of a linear motion (LM) guide through a experimental result and theoretical analysis. The stiffness in the LM guide is determined by the preloading due to the minus clearance between the ball bearing and the contact surface and it can be derived by Hertzian contact theory and the nonlinear motion of equation. The vibration analysis is performed using Lagrange equations and its result agrees with the experiment result. Using the sensitivity analysis on design parameters such as the contact angles of ball bearings and the eccentricity of mass center, the variation of the natural frequencies can be predicted.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.12
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• pp.1055-1062
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• 2008

Engineering materials have been studied and developed remarkably for a long time. But, few reports about marine propeller materials are presented. Recently, some researchers have studied the material strength of marine propellers. However, studies on parametric sensitivity and probabilistic distribution of fatigue life of propeller materials have not been made yet. In this study, a method to predict the probabilistic distributions of fatigue life of propeller materials is presented, and the influence of several parameters on the life distribution is discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1201-1208
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• 2001

Variable temperature anemometer(VTA) has greater sensitivity than a conventional constant temperature anemometer(CTA). In order to design a reliable VTA system, however, an elaborate photoconductive cell stabilizing circuit which plays a key role in setting wire-overheat ratio should be firstly developed. In this study, a stabilizing circuit which adopts proportional-integral analog controller was proposed and thoroughly tested for its accuracy and reproducibility. In contrast to the available circuit suggested by Takagi, the present circuit has characteristic that the resistance of a photoconductive cell increases with the increase of input voltage, which makes the current circuit very suitable for the design of VTA. Finally, VTA adopting stabilizing circuit was made and the enhanced sensitivity of the VTA was validated experimentally by comparing the calibration curves of VTA and CTA.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.135-142
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• 2002

Input shaping is a method for reducing residual vibration in computer controlled machines. Vibration is eliminated by convolving a sequence of impulses, an input shaper, with a desired system command to produce a shaped input. This paper shows the shape of sensitivity curve of input shaper as impulse interval T and analysis of robustness for input shaper on the z-plane. And a method is presented for designing equivalent input shaper considering sampling time $T_s$. And then we applied equivalent input shaper to crane system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1030-1036
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• 2001

A new mathematical model to determine the optimal gas temperatures in reheating furnace was proposed for the good quality of products. This model employs sensitivity method to calculate the optimal gas temperatures in each zone for heating the slab up to its discharging target temperature and for heating it uniformly. This method was validated by showing that the calculated discharging temperature of the slab was in a good agreement with its prescribed discharging target one through an off-line simulation.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.12-23
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• 1994

This paper proposes an optimal design software for the open-chain dynamic systems whose governing equations are expressed as differential equation. In this software, an input module and an automatic creation module of the equation of motion are developed to contrive the user's convenience. To analyze the equation of motion of the dynamic systems, variable-order and variable-stepsize Adams-Bashforth-Moulton predictor-corrector method is used to improve the efficiency. For the optimization and the design sensitivity analysis, ALM(augmented lagrange multiplier)method and adjoint variable method are adopted respectively. An output module with which the user can compare and investigate the analysis and the optimization results through tables and graphs is also provided. The developed software is applied to three typical dynamic response optimization problems, and the results compare very well with those available in the literature, demonstrating its effectiveness.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.931-935
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• 1991

본 연구에서는 유효응력확대계수로서 피로크랙 진전수명을 평가할 수 이용되 는 크랙열림비(본 논문에서는 후술하는 최대응력에 대한 크랙 열림응력의 비를 크랙 열림비로 하다)가 진전수명에 미치는 영향을 평가하기 위한것으로서, 제1보에서는 실 험에 의하여 크랙 열림점을 실측한 결과 측정입치에 따라 다른 값을 나타내며 수명평 가법 크랙 선단으로부터 떨어진 곳(크립게이지를 이용한 크랙마우스등)에서 측정한 크 랙 열림점 값을 이용함이 보다 정확함을 밝혔다.본 제2보에서는 크랙열림비가 수명 평가에 미치는 영향을 상기의 파라미터 영향도 평가수법을 이용하여 평가하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.270-277
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• 2006

Inverse radiation problems were solved for estimating boundary temperature distribution in a way of function estimation approach in an axisymmetric absorbing, emitting and scattering medium, given the measured radiative data. In order to reduce the computational time fur the calculation of sensitivity matrix, automatic differentiation and Broyden combined method were adopted, and their computational precision and efficiency were compared with the result obtained by finite difference approximation.. In inverse analysis, the effects of the precision of sensitivity matrix, the number of measurement points and measurement error on the estimation accuracy had been inspected using quasi-Newton method as an inverse method. Inverse solutions were validated with the result acquired by additional inverse methods of conjugate-gradient method or Levenberg-Marquardt method.