Dynamic Failure Characteristics of Metallic Sandwich Plate with Repeated Metallic Truss Cores Subjected to a Plane Strain Drop Impact Condition

안동규,선향선 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.1

Dynamic failure characteristics of a metallic sandwich plate with repeated metallic cores considerably affect the dynamic property and the functionality of the plate. The objective of this paper is to examine dynamic failure characteristics of a metallic sandwich plate with repeated metallic truss cores subjected to plane strain drop impact conditions via a three-dimensional finite element analysis. Dynamic failure modes of the metallic sandwich plate have been estimated using the residual deformed shape of the plate. Nondimensional impact parameters have been adopted to generalize the dynamic failure map (DFM). Limit curves for different dynamic failure modes have been estimated via a regression analysis using the limit impact conditions in dynamic failure plots (DFPs). DFMs of the metallic sandwich plate have been created using the limit curves and the DFPs. The effects of the non-dimensional impact parameters on dynamic failure characteristics of the metallic sandwich plate have been discussed. The relationship between nondimensional impact energy and non-dimensional absorbed energy has been estimated to investigate the energy absorption characteristics of the plate. Finally, it has been revealed that the initiation of the instability mode is prevented to obtain the desired performance of the metallic sandwich plate with repeated metallic truss cores.

백제토기 반(盤)의 출현 과정과 성격

우진영(Woo, Jinyoung) 한국고고학회 2021 한국고고학보 Vol.- No.121

본고에서는 백제 반(盤) 자료를 집성하고, 이를 바탕으로 속성 검토 및 형식 분류를 통해 백제 반의 변천양상을 살펴보았다. 더불어 주변 국가 자료와 비교를 통해 백제 반의 기원 및 출현 과정을 파악하고, 출토맥락을통해 백제 사회 내에서 반의 성격을 파악해 보았다. 먼저 백제 반의 속성 분석을 통해 태토, 굽 유무, 심도가 시간적 특성을 보이는 속성임을 파악하고 이를조합하여 6개의 형식으로 분류하였다. 그리고 선후관계를 파악할 수 있는 자료를 검토하여 4단계를 설정하였다.Ⅰ단계는 반이 등장하는 단계로 무굽(원저·평저)의 조질 및 중질의 태토로 제작된 심도Ⅰ형의 반 가1 형식만 확인된다. Ⅱ단계는 가1 형식이 이어지면서 새로운 유굽(B형식)의 반과 심도 Ⅱ형의 가2와 나1 형식이등장한다. Ⅲ단계에는 가1 형식은 점차 소멸되고, 가2·나1 형식이 이어지면서 새로운 가3 형식이 등장한다. 가3 형식은 기존과 달리 정질의 태토를 사용하여 제작된 반이다. Ⅳ단계는 기존의 형식이 이어지면서 가4, 나2 형식이 새롭게 등장한다. 가4, 나2 형식의 태토는 매우 정선되었으며 물레성형을 통해 제작되었고, 심도가낮아진다. 이를 바탕으로 백제 반의 등장과 성격을 살펴본 결과 반은 백제 한성기부터 등장하였으며, 고구려 토기제작의 기술적인 면과 중국 문화에 일부 영향을 받았음을 알 수 있었다. 또한 백제 내에서 반은 일상생활 용기로서 보편적인 사용이 이루어졌다고 보기는 어려웠다. This paper presents the results of research in which Baekje plate data were collected, its properties analyzed, and typological changes over time were identified. In addition, the origin and appearance of Baekje plates were identified through comparisons with examples from neighboring countries, and the characteristics of plates within Baekje society were identified through an examination of the excavated context. Firstly, an analysis of the properties of plates revealed that the base clay, presence of a foot, and plate depth were the properties demonstrating temporal characteristics. Based on this, the plates were classified into six types by combining the corresponding properties. In addition, by comparing sequence when possible (for both the plates and associated artifacts), four temporal stages were established. Stage I was when the plate first appeared, and only the ‘Ga 1-type’, a footless plate (rounded-bottom and flat bottom) with a type I depth and made of fine-grained and coarsegrained base clay, was identified. In Stage II, plates of the ‘Ga 1-type’ made of coarsegrained and medium-grained base clay continued to be manufactured, as in Stage I. However, unlike Stage I, footed plates (B type) were newly identified, and plates with a type II depth (lower than the type I depth) were also manufactured. In Stage III the ‘Ga 1-type’ plate gradually disappeared, and as the ‘Ga 2-type’ and ‘Na 1-type’ plates continued to be used, a new ‘Ga 3-type’ appeared. The newly introduced ‘Ga 3-type’ at this time was a plate made using fine-grained base clay, unlike previous examples. In Stage IV, the existing ‘Ga 2-type’, ‘Ga 3-type’, and ‘Na 1-type’ continued to be used, and the new ‘Ga 4-type’ and ‘Na 2-type’ plates, which were different from the previous examples, appeared. Very carefully selected base clay was used for the ‘Ga 4-type’ and ‘Na 2-type’ plates, which were manufactured using the throwing technique, and the depth of the plates became shallower. As a result of the examinination of the appearance and characteristics of Baekje plates, it was established that plates appeared from Baekje’s Hanseong period and were partially influenced by the technical aspects of Goguryeo pottery production and Chinese culture. In addition, plates were used as ritual equipment in Baekje, and it is unlikely that they were universally used as containers in everyday life.

Characteristics of noise generated by axial excitation of helical gears in shaft-bearing-plate system

박찬일 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.4

This work investigated the noise characteristics of a simplified gear system through the axial excitation of helical gears. The simplifiedgear system was modeled as a shaft-bearing-plate with helical gears. Four pole parameters of the shaft-bearing-plate system were used todetermine the longitudinal behavior of the system. The noise was modeled by sound radiation from the vibration of a circular platemounted in an infinite baffle. The shaft-bearing-plate model was validated by finite element and acoustic analyses. Using the validatedmodel, the noise characteristics of the system were investigated. According to the results, doubling the input torque increased the soundpressure level. An increase in plate thickness reduced the plate displacement, but did not reduce the noise. The noise level was lower foraluminum and magnesium plates than steel plates. An increase in the shaft diameter decreased the sound pressure level. Finally, a shortershaft led to higher natural frequencies and sound pressure levels.

사판식 액셜 피스톤 펌프의 사판 모멘트를 이용한 제어 특성 연구

주승원 한국산학기술학회 2024 한국산학기술학회논문지 Vol.25 No.6

본 연구에서는 사판식 액셜 피스톤 펌프에 레귤레이터를 적용하지 않고 펌프의 피스톤에 의해 발생하는 사판 모멘트를 이용하여 사판각을 제어하기 위한 관련 이론 분석 및 해석을 진행하였다. 해석을 위해 AMESim 소프트웨어를 이용하여 밸브 플레이트의 형상에 따른 실린더 내부 압력 변화와 사판의 회전 중심축의 오프셋을 통한 사판 모멘트를 분석하였다. 또한, 사판에 적용되는 스프링 개수, 스프링 상수, 스프링 초기하중 그리고 스프링 간 간격 특성을 이용하여 사판의 제어 특성에 대해 분석하였다. 본 연구의 핵심은 제어 변수를 조절하여 피스톤에 의해 발생하는 사판 모멘트를 이용하여 사판식 액셜 피스톤 펌프에 일정 마력 제어 기능을 구현할 수 있는 가능성을 확인한 것이다. In this study, theoretical analysis and simulations were conducted to control the Swash plate angle using the swash plate moment generated by the piston of the pump without applying a Regulator to the Swash plate type axial piston pump. For this simulation, AMESim software was used to analyze the swash plate moment through the offset of the rotational central axis of the swash plate and the change in cylinder internal pressure according to the shape of the valve plate. In addition, the control characteristics of the swash plate were analyzed using the number of springs, spring rate, spring preload, and spring gap characteristics. The key aim of this study was to confirm the possibility of implementing a constant horsepower control function on a swashplate-type axial piston pump using the swash plate moment generated by the piston by adjusting the control variables.

무전해 구리도금 된 흑연 섬유의 발열 특성

이경민 ( Kyeong Min Lee ),김민지 ( Min-ji Kim ),이상민 ( Sangmin Lee ),여상영 ( Sang Young Yeo ),이영석 ( Young-seak Lee ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.2

To improve heating characteristics of graphite fibers, graphite fibers were copper-plated by electroless plating. The Cu-plated graphite fibers were investigated by thermos-gravimetric analysis in air to calculate quantities of copper on surface of graphite fiber according to plating time. Also, the surface temperature with applied voltage was observed by thermos-graphic camera using a strand of graphite fiber. According to the increment of plating time, the higher quantities of plated copper on graphite fiber were obtained. The electric conductivity of plated graphite fiber for 20 minutes was resulted in 1594.3 S/cm, and surface temperature of this sample showed the maximum temperature 57.2 ℃. These result could be attributed that copper having great electric conductivity are growing on graphite fiber and followed improving heating characteristics.

게이트 필드플레이트 구조 최적화를 통한 AlGaN/GaN HEMT의 항복전압 특성 향상

손성훈(Sung Hun Son),김태근(Tae Geun Kim) 大韓電子工學會 2011 電子工學會論文誌-SD (Semiconductor and devices) Vol.48 No.5

본 논문에서는 AlGaN/GaN HEMT의 항복 전압 특성 향상을 위해 2차원 소자 시뮬레이터를 통하여 게이트 필드 플레이트 구조를 최적화하였다. 필드플레이트 길이, 절연체 종류, 절연체 두께 변화 등의 세가지 변수를 이용하여 시뮬레이션을 진행하였으며 그에따른 전기장 분포의 변화와 항복전압 특성을 확인하였다. 필드플레이트 구조를 최적화 시킴으로서 게이트 에지부분과 필드플레이트 에지부분에 집중 되어있던 전기장이 효과적으로 분산된다. 그에 따라 애벌런치 효과가 줄어들게 되어 항복전압 특성이 향상된다. 결론적으로 최적화된 게이트 필드플레이트 구조는 일반적인 구조에 비해 항복특성을 약 300% 이상 향상시킬 수 있다. In this paper, we optimize the gate field plate structure to improve breakdown characteristics of AlGaN/GaN HEMT by two-dimensional device simulator. We have simulated using three parameters such as field-plate length, types of insulator, and insulator thickness and thereby we checked change of the electric field distribution and breakdown voltage characteristics. As optimizing field-plate structure, electric fields concentrated near the gate edge and field-plate edge are effectively dispersed. Therefore, avalanche effect is decresed, so breakdown voltage characteristic is increased. As a result breakdown characteristics of optimized gate field-plate structure are increased by about 300% compared to those of the standard structure.

SOI LDMOS에서 선형 Field Plate 의 항복전압 특성에 관한 연구

배동건 거제전문대학 1997 論文集 Vol.5 No.-

An SOI LDMOS(Silicon-On-Insulator Laterally Double diffused MOS) with tapered field plate which has more superior breakdown characteristics in comparison with conventional SOI LDMOS with stepped field plate is proposed. Comparing two structures using 2-D simulator, MEDICI, the proposed structure shows that the surface electric field can be decreased more effectively and has wider range of drift region thickness and of field plate length. The two structures are fabricated and compared in terms of breakdown characteristics. The enhanced breakdown voltage of LDMOS with tapered field plate is verified by 143V of breakdown voltage in excess of 74%.

Simulation of an X-ray Fresnel Zone Plate with Nonideal Factors

Chen, Jie,Fan, Quanping,Wang, Junhua,Yuan, Dengpeng,Wei, Lai,Zhang, Qiangqiang,Liao, Junsheng,Xu, Min Optical Society of Korea 2020 Current Optics and Photonics Vol.4 No.1

Fresnel zone plates have been widely used in many applications, such as x-ray telescopes, microfluorescence, and microimaging. To obtain an x-ray Fresnel zone plate, many fabrication methods, such as electron-beam etching, ion-beam etching and chemical etching, have been developed. Fresnel zone plates fabricated by these methods will inevitably lead to some nonideal factors, which have an impact on the focusing characteristics of the zone plate. In this paper, the influences of these nonideal factors on the focusing characteristics of the zone plate are studied systematically, by numerical simulations based on scalar diffraction theory. The influence of the thickness of a Fresnel zone plate on the absolute focusing efficiency is calculated for a given incident x-ray's wavelength. The diffraction efficiency and size of the focal spot are calculated for different incline angles of the groove. The simulations of zone plates without struts, with regular struts, and with random struts are carried out, to study the effects of struts on the focusing characteristics of a zone plate. When a Fresnel zone plate is used to focus an ultrashort x-ray pulse, the effect of zone-plate structure on the final pulse duration is also discussed.

Simulation of an X-ray Fresnel Zone Plate with Nonideal Factors

Jie Chen,Quanping Fan,Junhua Wang,Dengpeng Yuan,Lai Wei,Qiangqiang Zhang,Junsheng Liao,Min Xu 한국광학회 2020 Current Optics and Photonics Vol.4 No.1

Fresnel zone plates have been widely used in many applications, such as x-ray telescopes, microfluorescence, and microimaging. To obtain an x-ray Fresnel zone plate, many fabrication methods, such as electron-beam etching, ion-beam etching and chemical etching, have been developed. Fresnel zone plates fabricated by these methods will inevitably lead to some nonideal factors, which have an impact on the focusing characteristics of the zone plate. In this paper, the influences of these nonideal factors on the focusing characteristics of the zone plate are studied systematically, by numerical simulations based on scalar diffraction theory. The influence of the thickness of a Fresnel zone plate on the absolute focusing efficiency is calculated for a given incident x-ray’s wavelength. The diffraction efficiency and size of the focal spot are calculated for different incline angles of the groove. The simulations of zone plates without struts, with regular struts, and with random struts are carried out, to study the effects of struts on the focusing characteristics of a zone plate. When a Fresnel zone plate is used to focus an ultrashort x-ray pulse, the effect of zone-plate structure on the final pulse duration is also discussed.

A comprehensive analysis of horizontally polarized shear waves in a thin microstructural plate

Vikas Sharma,Satish Kumar 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.4

Horizontally polarized shear waves (SH) have numerous applications in various scientific, engineering, and medical fields. The study deals with an investigation of SH-waves in a thin microstructural plate. The plate has been mathematically modelled by employing size dependent consistent couple stress theory, which involves a length parameter, known as characteristic length. Characteristic length is assumed to be of the order of internal microstructures of the material. Dispersion relations have been calculated for the propagation of SH-waves using different set of boundary conditions. Group velocity of the SH-waves has been calculated by using an analytical approach. The mathematical results obtained in the problem are discussed in detail and the impacts of characteristic length parameter and thickness of plate are presented on phase velocity of SH-waves through graphical illustrations.