HDD용 구동 및 현가 장치의 축소 진동 모델의 생성 및 해석

한정삼(Jeong Sam Han) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

In the case of mechanical control systems, it is highly useful to be able to provide a compact model of the mechanical system to control engineers using the smallest number of variables, while still providing an accurate model. The reduced mechanical model can then be inserted into the complete mechanical control system models and used for system-level dynamic simulation. In this paper, a moment-matching based model order reduction (MOR) which reduces the number of degrees of freedom of an original finite element model via the Arnoldi process is considered to study the dynamic responses of a HDD actuator and suspension system.

Krylov 부공간을 이용한 압전구조체의 모델차수축소법

한정삼(Jeong Sam Han) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

A piezoelectric device is widely used for actuation and sensing in many applications and its design often requires calculation of a frequency response which is computationally very expensive when an interesting frequency is up to a high range or when a wide range of actuating frequency should be considered. To alleviate the problem of high computation cost, this paper presents the Krylov subspace-based model order reduction (MOR) for frequency responses of a piezoelectric structure. The frequency response analysis can be performed efficiently from reduced low dimensional numerical models generated by the model order reduction which reduces the number of degrees of freedom of an original ANSYS finite element models via the Arnoldi process. A piezoelectric bimorph actuator and micro gyroscope were studied to demonstrate the feasibility of the suggested simulation method for the piezoelectric harmonic analysis.

모델차수축소기법을 이용한 초임계압 증기터빈 로터의 이상상태 진동 모사

한정삼(Jeong Sam Han),권기범(Ki Beom Kwon) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

터보분자펌프의 회전체 동해석

한정삼(Jeong Sam Han) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10

모델차수축소기법을 이용한 회전체의 동해석

한정삼(Jeong Sam Han) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.4

모델차수축소법을 이용한 너클의 효율적인 진동해석

한정삼(Jeong Sam Han),에브게니 루디니(Evgenii B. Rudnyi),얀 코빙크(Jan G. Korvink) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.4

Currently most practical vibrational and structural problems in automotive suspensions require the use of the finite element method to obtain their structural responses. When the finite element model has a very large number of degrees of freedom, the harmonic and dynamic analyses are computationally too expensive to repeat within a feasible design process time. To alleviate the computational difficulty, this paper presents a moment-matching based model order reduction (MOR) which reduces the number of degrees of freedom of the original finite element model and speeds up the necessary simulations with the reduced-size models. The moment-matching model reduction via the Arnoldi process is performed directly to ANSYS finite element models by software mor4ansys. Among automotive suspension components, a knuckle is taken as an example to demonstrate the advantages of this approach for vibrational simulation.

모드중첩법 및 최소자승법을 통한 고충격 압저항 미소가속도계의 출력전압 해석

한정삼(Jeong Sam Han),권기범(Ki Beom Kwon) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.7

본 논문에서는 여러 가지 충격하에서 압저항 고충격 미소가속도계의 과도 출력전압의 계산시 발생하는 방대한 계산 시간 문제를 모드중첩법 및 최소자승법을 이용하여 압저항 미소가속도계의 실시간 출력전압 계산이 가능하도록 효율적인 출력전압 과도해석 방법을 제안한다. 우선 정적 압저항-구조 해석을 통하여 미소가속도계의 변위와 출력전압을 계산하고 출력전압을 특정 위치의 변위에 관한 2차 다항식으로 근사화하여 그 회귀계수를 최소자승법을 통하여 결정한다. 이후에 모드중첩법을 통하여 여러 방향의 고충격하에서 미소가속도계의 과도 변위응답을 계산하고, 이 변위응답을 변위로 표현되는 출력전압 근사식에 대입하여 과도 출력전압을 예측한다. 100,000 G 고충격파, 사인파, 계단파 및 사각파 등의 여러 가지 고충격 입력에 대한 압저항 미소가속도계의 수치예제를 통하여 제안한 방법의 정확성 및 효율성을 검증하였다. The transient analysis for the output voltage of a piezoresistive microaccelerometer takes a relatively high computation time because at least two iterations are required to calculate the piezoresistive-structural coupled response at each time step. In this study, the high computational cost for calculating the transient output voltage is considerably reduced by an approach integrating the mode superposition method and the least square method. In the approach, data on static displacement and output voltage calculated by piezoresistive-structural coupled simulation for three acceleration inputs are used to develop a quadratic regression model, relating the output voltage to the displacement at a certain observation point. The transient output voltage is then approximated by a regression model using the displacement response cheaply calculated by the mode superposition method. A high-impact microaccelerometer subject to several types of acceleration inputs such as 100,000 G shock, sine, step, and square pulses are adopted as a numerical example to represent the efficiency and accuracy of the suggested approach.

전자기 로렌츠력을 이용한 다중안정성 마이크로 액추에이터의 비선형 구조 및 전기-열 해석

한정삼(Jeong Sam Han) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.8

본 논문에서는 작동 평면상의 네 위치에서 사중안정점을 가지는 신개념 전자기형 마이크로 액추에이터의 구조체와 전자기 로렌츠력을 이용하는 구동 방식을 제시하고, 이의 타당성을 비선형 구조해석 및 전기-열해석을 통하여 검증하였다. 사중안정성 액추에이터의 구현을 위해서 관련 분야에서 널리 연구되고 있는 쌍안정성 액추에이터의 개념을 확장 응용하였다. 비선형 유한요소해석을 이용하여 사중안정성 미소 구조체의 정적 해석과 과도동적 해석을 수행함으로써 액추에이터 구조체의 다중안정성 유무를 파악하고 이 결과를 분석하여 구조체 설계에 반영하였다. 사중안정성 미소 구조체를 도체화하여 자기장 내에서 구조체에 전류를 통할 때에 발생하는 로렌츠력으로 평면상의 네 안정점으로 구조체를 구동할 수 있도록 고안하고, 그 때 필요한 구동전류의 크기 및 전자기 구동에 의한 주울열에 의한 온도분포를 계산하여 전반적인 타당성을 검토하였다. 본 논문은 지금까지의 관심 대상인 쌍안정성의 이용이 아니라 더욱 확장된 다중안정성을 가진 미소 액추에이터의 구조체와 전자기 구동방법을 제안하여 향후에 다중안정성을 필요로 하는 마이크로 시스템에 활용될 수 있도록 하는데 그 의미가 있다. In this paper, the design and nonlinear simulation of a multistable electromagnetic microactuator, which provides four stable equilibrium positions within its operating range, have been discussed. Quadstable actuator motion has been made possible by using both X- and Y-directional bistable structures with snapping curved beams. Two pairs of the curved beams are attached to an inner frame in both X- and Y-directions to realize independent bistable behavior in each direction. For the actuation of the actuator at the micrometer scale, an electromagnetic actuation method in which Lorentz force is taken into consideration was used. By using this method, micrometer-stroke quadstability in a plane parallel to a substrate was possible. The feasibility of designing an actuator that can realize quadstable motion by using the electromagnetic actuation method has been thoroughly clarified by performing nonlinear static and dynamic analyses and electrothermal coupled-field analysis of the multistable microactuator.

고충격 미소가속도계의 압저항-구조 연성해석 및 최적설계

한정삼,권순재,고종수,한기호,박효환,이장우,Han, Jeong-Sam,Kwon, Soon-Jae,Ko, Jong-Soo,Han, Ki-Ho,Park, Hyo-Hwan,Lee, Jang-Woo 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.1

A micromachined silicon accelerometer capable of surviving and detecting very high accelerations(up to 200,000 times the gravitational acceleration) is necessary for a high impact accelerometer for earth-penetration weapons applications. We adopted as a reference model a piezoresistive type silicon micromachined high-shock accelerometer with a bonded hinge structure and performed structural analyses such as stress, modal, and transient dynamic responses and sensor sensitivity simulation for the selected device using piezoresistive-structural coupled-field analysis. In addition, structural optimization was introduced to improve the performances of the accelerometer against the initial design of the reference model. The design objective here was to maximize the sensor sensitivity subject to a set of design constraints on the impact endurance of the structure, dynamic characteristics, the fundamental frequency and the transverse sensitivities by changing the dimensions of the width, sensing beams, and hinges which have significant effects on the performances. Through the optimization, we could increase the sensor sensitivity by more than 70% from the initial value of $0.267{\mu}V/G$ satisfying all the imposed design constraints. The suggested simulation and optimization have been proved very successful to design high impact microaccelerometers and therefore can be easily applied to develop and improve other piezoresistive type sensors and actuators.

압전-구조해석을 이용한 볼트체결 평판의 상태 진단을 위한 CNN 생성 및 평가

한정삼(Jeong Sam Han),이수범(Soobum Lee) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11