• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 추계학술대회 논문집
• /
• pp.89-92
• /
• 1996

In this paper, we mention the study on the sensing function of amorphous magneto- striction wire with about 125${\mu}{\textrm}{m}$$\Phi$ in diameter. The wire in fabricated by using injection and quenching method under the high speed rotating water flow. The wire\`s compotion is (Fe$_{75}$ $Co_{25}$)$_{77}$Si$_{8}$B$_{15}$ , and generates sharp Matteucci voltage by large Barkhausen jump effect even the weak magnetic field. In this study, we don\`t use pick-up coil. Instead, we apply external magnetic field of 3.6Oe in the direction orthogonal to the wire. Then, we detect Matteucci voltage of 1.lmV to both side of 20cm amorphous-wire. Thus, we find that the fabricated wire has the function necessary as the high sensitive sensor material.l.al.l.

• Structural Engineering and Mechanics
• /
• 제69권6호
• /
• pp.637-649
• /
• 2019

In the current research paper, a quasi-3D beam theory is developed for free vibration analysis of functionally graded microbeams. The volume fractions of metal and ceramic are assumed to be distributed through a beam thickness by three functions, power function, symmetric power function and sigmoid law distribution. The modified coupled stress theory is used to incorporate size dependency of micobeam. The equation of motion is derived by using Hamilton's principle, however, Navier type solution method is used to obtain frequencies. Numerical results show the effects of the function distribution, power index and material scale parameter on fundamental frequencies of microbeams. This model provides designers with guidance to select the proper distributions and functions.

• Structural Engineering and Mechanics
• /
• 제71권1호
• /
• pp.89-98
• /
• 2019

In this study, the mechanical bending behaviors of functionally graded porous nanobeams are investigated. Four types of porosity which are, the classical power porosity function, the symmetric with mid-plane cosine function, bottom surface distribution and top surface distribution are proposed in analysis of nanobeam for the first time. A comparison between four types of porosity are illustrated. The effect of nano-scale is described by the differential nonlocal continuum theory of Eringen by adding the length scale into the constitutive equations as a material parameter comprising information about nanoscopic forces and its interactions. The graded material is designated by a power function through the thickness of nanobeam. The beam is simply-supported and is assumed to be thin, and hence, the kinematic assumptions of Euler-Bernoulli beam theory are held. The mathematical model is solved numerically using the finite element method. Numerical results show effects of porosity type, material graduation, and nanoscale parameters on the static deflection of nanobeam.

• 한국실내디자인학회논문집
• /
• 제20권1호
• /
• pp.24-32
• /
• 2011

The study was to grasp features of new material applicable to housing space in the sustainable side by analyzing materialistic features of new material and features of sustainable material with sustainable new material. Through analysis on sustainable new material, the study deducted the below conclusion. First, through the precedent studies, the characteristics of sustainable materials have been classified into eight categories : friendly healthiness, non-toxicity, comfortableness, naturality, recycling, harmlessness of environment, separate collection, reusability. After the criteria have been brought up from new material applicable to housing space in the sustainable. Second, in materialistic Characteristics of new material, 'New Process' was mainly applied. There was no any new material applied to 'new raw material'. Therefore, it is thought that it is necessary to study on development of perfectly new material and to study on new material to apply material used in other fields to finishing material of dwelling space. Third, in Characteristics of sustainable material, 'Re-serviceability' appeared most and 'Non-toxicity' and 'Recycling' appeared in the next. 'Friendly Healthiness' and 'Separate collection' appeared only one on the other side. Therefore, it is judged that it is necessary to develop and study new material including health components considering user's health, function for health increase and function to grope comfort for humans. Finally, after researching and analysis the criteria by recently presented the new material, it has been concluded that the standard can be used as the criteria of new material for the possibility of application in housing space. On the basis of the study, the author will carry out analysis on sustainable new material minutely and utilize it as basic data to suggest a standard of sustainable new material applicable to dwelling space in the future.

• 대한조선학회논문집
• /
• 제42권3호
• /
• pp.284-289
• /
• 2005

A structural design system is developed for the optimum design of double hull tankers based on the multi-objective function method. As a multi-objective function method, Pareto optimal based random search method is adopted to find the minimum structural weight and fabrication cost. The fabrication cost model is developed by considering the welding technique, welding poses and assembly stages to manage the fabrication man-hour and process. In this study, a new structural design is investigated due to the rapidly increased material cost. Several optimum structural designs on the basis of high material cost are carried out based on the Pareto optimal set obtained by the random search method. The design results are compared with existing ship, which is designed under low material cost.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.418-421
• /
• 2003

Today, much terminologies such as noise spectrum, Sharpness, contrast, MTF had been defined for Image quality revaluation of radiation Image. Since development of Xeroradiography In the 1970s, Digital radiation detector that use amorphous selenium was developed. The aim of this research is to analyze physical phenomenon of digital radiation detector that use amorphous selenium. Result of Monte Carlo simulations on amorphous selenium based on physical properties(creation of electron-hole pairs) by induced x-ray are described. From the simulation, intrinsic point spread function(PSF) was found and used to observe modulation transfer function(MTF). We investigated how PSF and MTF changed with various x-ray energy. This result can be used to design digital x-ray detector based on a-Se.

• 대한기계학회논문집
• /
• 제16권7호
• /
• pp.1341-1350
• /
• 1992

본 연구에서는 시험 재료의 특성을 가장 잘 나타낼 수 있으며 시험 자료밖의 범위에서도 물리적 타당성을 갖는 변형 에너지 함수를 찾기 위한 방법의 일환으로 기 존의 여러 방법들을 이용하여 동일한 시험 자료에 적용함으로써, Rivlin 형태와 Ogden 형태에 대한 재 조사를 실시하였다. 그리고 비선형 대변형 재료의 실제 사용 예로서 앞에서 언급한 타이어용 고무를 들 수 있는데 이들에 대한 변형 에너지 함수를 결정하 기 위한 시험자료는 실제적 문제때문에 단순 인장과 같은 비교적 간단한 경우에 대하 여 한정되어 있으므로, 이러한 자료로부터 여러 종류의 하중 상태를 예측할 수 있는 변형 에너지 함수를 찾고자 하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.1186-1190
• /
• 1995

This paper is focused on the formulation of explicit closed-form functions describing the performance measures of the general flexible manufacturing system (FMS)according to the strategy of material handling system(MHS). the performance measures such as the production rate, the production lead-time and the utilization rate of the general FMS are expressed, respectively, as the explicit closed-form functions of the part processing time, the service rate of the material handling system (MHS) and the number of machine tools in the FMS. For this, the gensral FMS is presented as a generalized stochastic Petri net model, then, the moment generating function (MGF) based approach is applied to obtain the steady-state probabity formulation. Based on the steady-state formulation, the explicit closed-form functions for performance measures of the probability FMS can be obtained. Finally, the analytical results are compared with the Petri net simulation results to verify the validity of the suggested method. The paper is of significance in the sense that it provides a comprehensive formula for performance measures of the FMS even to the industry engineers and academic reademic resuarchers who have no background on Markov chain analysis method or Petrinet modeling

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2002년도 봄 학술발표회 논문집
• /
• pp.491-498
• /
• 2002

Dredged and reclaimed soft clays form slurry state which is very high water content and very low shear strength, experience large self-weight consolidation, nonlinear compressibility and permeability phenomenon would take place. In this case, a material functions which represent variety effective stress-void ratio-permeability relation (especially very low effective stress), are should be determined to predict nonlinear finite strain consolidation phenomenon forehand In this study, large slurry consolidometer with a 380mm diameter and a 1400mm height which is able to consolidation and permeability test, was developed to determine material function of very soft clay with a 500% initial water content clay, self-weight consolidation and low stress level consolidation (1Kpa, 3Kpa, 6Kpa, 12Kpa) was conducted and after each consolidation step permeability test also conducted. after final consolidation step, a constant rate of strain consolidation was conducted with undisturbed sample obtained from the large consolidometer. On the above result, material function was determined and laboratory test was modelled to evaluate its validity, numerical analysis on th field was compared to other method.

• 한국CDE학회논문집
• /
• 제12권3호
• /
• pp.220-232
• /
• 2007

Current geometric modeling and analysis are commonly based on B-Rep modeling and a finite elements method respectively. Furthermore, it is difficult to represent an object whose material property is heterogeneous using the B-Rep method because the B-Rep is basically used for homogeneous models. In addition, meshes are required to analyze a property of a model when the finite elements method is applied. However, the process of generating meshes from B-Rep is cumbersome and sometimes difficult especially when the model is deformed as time goes by because the topology of deforming meshes are changed. To overcome those problems in modeling and analysis including homogeneous and heterogeneous materials, we suggest a unified modeling and analysis method based on implicit representation of the model using R-function which is suggested by Rvachev. For implicit modeling of an object a distance field is approximated and blended for a complex object. Using the implicit function mesh-free analysis is possible where meshes are not necessary. Generally mesh-free analysis requires heavy computational cost compared to a finite elements method. To improve the computing time of function evaluation, we utilize GPU programming. Finally, we give an example of a simple pipe design problem and show modeling and analysis process using our unified modeling and analysis method.