논문 : 비물질적 표현특성을 이용한 미디어 벽체의 동적 회화 구성

고경진 ( Kyung Jin Ko ),이현수 ( Hyun Soo Lee ) 디자인융복합학회 2003 디자인융복합연구 Vol.2 No.1

비물질적 표현특성은 투명성, 일시성, 상호 관입성, 콜라주 등과 같은 표현특성으로 대표될 수 있다. 이러한 비물질적 표현특성은 정보화의 가속화에 따라 더욱 확산될 것으로 예상되며, 앞으로의 디자인 방향에 많은 영향을 미칠 것이다. 디자인 분야에 비물질적 표현특성을 보다 효과적으로 반영하기 위해서는 그 개념을 중문하게 이해하고 있어야 한다. 따라서, 본 논문에서는 비물질적 표현특성을 체계적으로 분석하고 분석의 결과를 바탕으로 미디어 스크린의 동적 회화 구성 방법을 제안하는데 연구의 목적을 두고 있다. 이를 위해 비물질적 표현특성을 크게 반영하고 있는 디자인 사례와 관련문헌을 이용하여 비물질적 표현특성을 도출해내고, 이를 표피적 특성, 공간적 특성, 매체적 특성 등의 세 가지로 나누어 설명한다. 그러고 이와 같은 비물질적 표현 특성을 반영한 미디어 스크린의 동적 회화 구성방법을 제안하고 있다. 미디어 스크린의 동적 회화 구성 방법을 보여 주기 위해 본 연구에서 사용하고 있는 사례는 몬드리안의 회화이다. 몬드리안의 회화를 사용한 이유는 회화의 구성 형태가 기하학적으로 구성되어 있기 때문에 회화의 구성에 대한 수정이 용이할 것이라고 생각하였기 때문이다. 이와 같은 미디어 스크린의 동적 회화 구성은 여러 분야에서 관림자의 심미적 욕구를 만족시키기 위해 활용될 수 있을 것이다. Dematerial Characteristics can be representative of many characteristics, such as Transparency, Simultaneity, Fluidity, Collage, etc... It is forecasted that these Dematerial Characteristics will be spreaded by the acceleration of the digital information wave. This study aims to interpret Dematerial Characteristics and develop methods for dynamic composition of painting in a media screen reflecting demateriality. In this study, Dematerial Characteristics are derived from building cases and related researches retlecting demateriality. And Dematerial Characteristics extracted from 6 papers related to demateriality are classified from the perspective of 3 types, such as surface characteristic, spacious characteristic and media characteristic. Dynamic composition of painting in a media screen means to transform an image in a media screen continuously or make a picture corresponding to a dweller`s requirements. This study describes 4 methods for dynamic composition of painting in a media screen. Those are methods for composition of painting by color changeability, transparency changeability, picture changeability, pattern changeability. To show Dynamic Composition of Painting in a media screen, this study has used Mondrian`s painting as a case. Because Mondrian`s painting is composed of geometrical composition. it is ease to modify composition of painting. As we know it, Dynamic Composition of Painting in a media screen can be applied to satisfy dweller`s aesthetic desires.

EXPERIMENTAL INVESTIGATION OF CHARACTERISTICS OF PRESSURE MODULATION IN A FUEL INJECTION SYSTEM

D. HUANG,M.-C. LAI 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.1

A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future. A piezoelectric atomization device achieves fuel pressure modulation through vibration of a piezoelectric pressure modulator. As a consequence, the fast alternating and slow moving streams collide with each other and further break up the fuel drop. In this paper, an experimental investigation was carried out to study the fluid dynamic characteristics of the spray atomization process of automotive port fuel injectors with a piezoelectric pressure modulator. The investigation mainly focuses on: (a) the coupling characteristics between the piezoelectric stack and the hydraulic as well as the transfer characteristics of pressure modulation from the piezoelectric modulator to the point above the orifice; (b) the time history of the pressure dynamic response at the point above the orifice under a typical modulation frequency, which reflects the variation of pressure modulation while the fuel injector is working; and (c) the time-variation characteristics related to mechanical structure and fluid dynamics. The experimental results expose some important dynamic characteristics of pressure modulation, which will be very significant and lead us to greatly improve the fuel injection system, optimize the control parameters and implement spray atomization with a high quality performance in the near future.

Effect of clearances in rolling element bearings on their dynamic performance, quality and operating life

Mostafa Yakout,M. G. A. Nassef,Soheir Backar 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.5

The performance of rolling element bearings is one of the machine quality measures in industry. The fatigue life and performance of rolling element bearings depends mainly on the dynamic characteristics of those bearings. This paper studied the effect of the internal radial clearance on the damping characteristics, natural modes of vibration, and fatigue life of rolling element bearings. Vibration modal analysis was performed on rolling bearings of the same size and type to measure their dynamic characteristics. These dynamic characteristics include the natural frequency of the first mode of vibration, damping, and amplitude of frequency response function at resonance. The internal radial clearances of these bearings were measured. A statistical analysis was performed to study the correlation between the internal radial clearance and the dynamic characteristics of rolling bearings. It was found that the damping ratio of the bearing assembly increased by reducing the internal radial clearance of the bearing. Similarly, rolling bearings that have large internal clearances showed short predicted fatigue life. It is concluded that the dynamic characteristics, and consequently the dynamic performance, of rolling bearings are significantly affected by the internal radial clearance.

Dynamic Characteristics of the Multistage Planetary Gear Transmission System Based on a Stochastic Load

Congfang Hu,Gaode Geng,Xianxian Liu,Shiping Yang,Xinzi Tang 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.4

Multistage planetary gear transmission has a large speed ratio, compact structure and large load capacity in engineering practice. However, its vibration affects the performance and reliability of the transmission, especially under a stochastic load condition with different dynamic characteristics. In this context, the dynamic behavior of a four-stage planetary gear transmission system is investigated using the lumped-parameter model. First, the translation-torsion dynamics model of the multistage planetary gear transmission system is established. Then, the natural frequency and the effect of meshing stiffness and component mass on the natural frequency are investigated. Further, the dynamics equation of the planetary gear transmission system is solved by the Runge–Kutta method, and the damped dynamic response with an equivalent load and the dynamic responses with stochastic loads are analyzed. Notably, the displacement amplitude increases with the increment of the stochastic load. In addition, the frequency domain response under 50%, 75%, 100% and 120% of the equivalent torque are studied. Lastly, a test rig is built for a yaw drive in a wind turbine with the four-stage planetary gear transmission system, and the vibration of the ring gear of the second stage and output shaft are tested with 50%, 75%, 100% and 120% of equivalent load. The experiment results verify the correctness of the theoretical dynamic model of the multistage planetary gear transmission system.

Investigation on large turbo-generator stator end winding dynamic characteristics based on response surface method

Zhao, Yang,Xiao, Yang,Lu, Sheng,Sun, Hao,Huo, Wenhao,Liao, Yong The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10

The natural frequencies corresponding to the particular mode shapes of a large turbo-generator must not be in the resonance region before delivery. Different parameters may clearly affect these dynamic characteristics. Different from other studies, this paper introduces a method for obtaining the inherent characteristics of end winding in a short period of time under multiple simultaneously changing parameters. The proposed process is based on the response surface method (RSM). In this method, the main concerned natural frequencies were taken as the critical index to describe the dynamic behaviors of the end winding, with which the mathematical relationship between the dynamic characteristics and design variables was analyzed. First, the stiffness of the rings, stiffness of the radial braces and number of pins bonded to the radial braces were used as samples for orthogonal experimental design. Then, the natural modes and frequencies of 25 different samples were acquired by conducting modal analysis with ABAQUS software. Utilizing these dynamic results, a second-order polynomial response surface model was established to describe the relationships between natural frequencies and these three different parameters. Then, the quality of this model was verified by calculating the valuating indexes for comparison with support vector regression (SVR). With the response surface model, the variation regularities of the natural frequencies and modes due to the above parameters were discussed. The method proposed in this paper can enable natural frequencies in the whole design space to be quickly determined without finite-element analysis, greatly improving the development efficiency and laying a foundation for dynamic response prediction during normal operation with different parameters and additional large turbo-generator stator end winding optimization.

Dynamic axial and radial temperature prediction of multi-plate frictional wet clutches in vehicle transmissions with the thermal resistance network method

Tianyan Liu,Xiangyang Xu,Minghui Zhang,Runbo Zhang,Yue Wu,Hongzhi Ji,Yanfang Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Under the engaging process, excessive temperature of clutch plates may lead to thermal failure. Existing research has failed to find the hot spot and the radial temperature difference real-timely. They also neglected the influence of dynamic sliding process and hydraulic characteristics. Thus, a multi-domain dynamic model of the whole clutch was proposed, involving the mechanical dynamics, the hydraulic dynamics and thermics. With the thermal resistance network method, the real-time axial and radial temperature prediction of clutch plates was realized. The highest temperature occurs on the friction pairs of axial middle and the maximum value occurs on the radial 5th mass. Compared with the results by FEM, the deviation is about 6.5 %, but the time duration is reduced significantly. Furthermore, the influence of the outer hub vibration (160 Hz, 0.2 Hz) on the dynamic characteristics was discussed. This work was tested to be an effective and good basis for the health prediction of wet clutches.

Dynamic Characteristics Simulation for a Simplex Swirl Injector

박홍복(Hongbok Park) 한국항공우주학회 2006 韓國航空宇宙學會誌 Vol.34 No.9

스월 인젝터의 비선형 동적특성을 모사할 수 있는 수치해석 모델을 개발하여 인젝터내의 정적/동적 특성을 분석하였다. Boundary Element Methods (BEMs)을 적용한 수치모델은 유체 경계면 산출에 매우 유리한 장점이 있어 표면의 불안정성 해석에 유용하게 적용되어 왔다. 이전의 연구 결과에서는 스월효과를 고려할 수 있도록 확장된 수치모델을 이용하여 인젝터의 형상을 고려한 정적특성을 보여주었다. 본 논문에서는 유입 흐름에 교란이 발생했을 때 인젝터의 각 구성요소에서의 동적응답을 분석하였고, 이론적 결과와 비교하여 수치모델에 대한 타당성을 검증하였다. 본 수치해석 결과는 입력류에서의 교란이 각 인젝터 구성품을 지나면서 감쇠/증폭되고 위상차를 만들게 되는 과정을 잘 모사하고 있다. 개발된 수치모델은 인젝터의 다양한 설계변수들이 유동특성에 미치는 효과 분석과 이론적 모델로는 예측이 어려운 비선형 영역에서의 동적 응답특성 분석에 유용하게 적용될 수 있을 것이다. A fully nonlinear model accounting for swirling effect has been applied in analyzing the dynamic response for a classical swirl injector. The current work applied highly accurate Boundary Element Methods (BEMs) in assessing its static and dynamic characteristics. On the basis of moving surface treatment method and surface instability study, which are obtained from the previous static characteristics analysis in pressure-swirl injectors, this work was expanded for analyzing the dynamics of a classical swirl injector. The dynamic response through injector components for disturbed inflow condition was investigated. The modified code was validated from comparison with the theoretical result for a typical swirl injector. Clearly the simulated result shows the interesting characteristics of swirl injectors to provide either amplification or damping of the input disturbance through each component. These results give promise in applying the current model to nonlinear dynamic characteristics of swirl injectors.

Vibration characteristic analysis of gearbox based on dynamic excitation with eccentricity error

Wen Liu,Hang Zhao,Tengjiao Lin,Biao Gao,Yun Yang 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

In this study, the vibration characteristics of gearbox considering the eccentricity error and the friction excitation of helical gear pair were evaluated theoretically and experimentally. A geometric model of a single-stage helical gear pair with eccentricity error was established to obtain the calculation formula of the length of the dynamic contact line and the friction excitation. The multi-degree-of-freedom dynamic model of the transmission system was established considering the influences of tooth friction, support stiffness and damping, meshing stiffness and damping, static error, and dynamic tooth backlash. Then, the dynamic meshing forces of the system were obtained and applied to the gearbox for vibration response analysis using mode superposition method. A correlation test rig was developed to measure vibration under different operating conditions for verifying the correctness of the simulation models. Comparison between simulation and test was performed to demonstrate the accuracy of the proposed model in predicting vibrations. Results showed that eccentricity greatly influenced the overall vibration characteristics. The relative error between measurement and prediction can be significantly reduced by considering the eccentricity error in the dynamic model of transmission system.

Elevated Temperature Effect on the Dynamic Characteristics of Steel Columns and Frames

Yunus Emrahan Akbulut,Ahmet Can Altunişik,Hasan Basri Başağa,Sara Mostofi,Ayman Mosallam,Louai F. Wafa 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.3

Fire performance of load bearing elements in steel buildings such as columns and frames has major importance for structural designers. This study aims to assess the elevated temperature eff ect on dynamic characteristics of steel columns and frames by conducting sequential heat transfer and modal analyses. A series of fi nite element analyses including heat transfer analysis aere performed on 62 diff erent steel columns and frames. Three-hour part of ISO 834 fi re curve is taken into consideration in the analysis. Modal analyses are conducted for the purpose of providing a more comprehensive image of dynamic characteristics in specifi c duration of elevated temperature. The presented study accommodates the eff ect of various steel profi le types, cross-sectional dimensions and exposure durations on changes in dynamic characteristics. The outcomes of the performed parametric study revealed the decrease in natural frequencies with the temperature growth. The research has also shown the existence of a correlation between temperature variations and changes in mode shapes. The change in mode shapes depends on the profi le type. Mode shapes do not change depending on the temperature in some profi le types, while in some profi le types they change after a certain temperature. The obtained results of the performed sequential analyses are presented in forms of tabulated data and approximate formulas. They can facilitate the damage detection process and contribute in required structural health monitoring measurements while enhance the accuracy of damage assessment for fi re exposed steel structures.

젠더특성에 따라 조직문화가 동적역량을 매개로 조직유효성에 미치는 영향

곽효근 ( Kwag Hyo Keun ),서철승 ( Seo Cheol Seung ),이상진 ( Lee Sang Jin ) 한국경영공학회 2019 한국경영공학회지 Vol.24 No.1

Many companies attempt to transform themselves into creative organizations to create high performance. Organizational culture and dynamic capabilities are essential to make a creative organization. As the participation of women in society is more prevalent than ever, enterprises should have more concern on creating an environment that maximizes the capability of women as a way of improving the business performance. The purpose of this study is to verify the mediating effect of dynamic capabilities that affects creativity for the organizational culture to influence organizational effectiveness in a rapidly changing environment, the fourth Industrial Revolution. Furthermore, this research investigates differences in organizational culture and dynamic capabilities according to gender characteristics. The result of this research is as followings. Rational culture affected to organizational effectiveness, however, Hierarchical culture affected only to creativity as a sub-factor of organizational effectiveness. Absorptive transformation capabilities as a sub-factor of dynamic capabilities mediated organizational culture and organizational effectiveness. And absorptive transformation capabilities positively affected to the organizational effectiveness in hierarchical culture as well. Rational culture positively affected to both dynamic capabilities and organizational effectiveness regardless of gender. In the rational culture, women are more involved to their job than men, and their performance is more than twice as high. Hierarchical culture influenced men's dynamic capabilities, but did not affect women's dynamic capabilities. Thus, this study represents that enterprises should build rational culture to business performance by utilizing the competence of female workers and have more concern on making environment for employees to exercise their dynamic capabilities.