• Title/Summary/Keyword: Free body diagram

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Robot Dynamic Analysis using Free-body-diagram (자동물체도를 이용한 로봇 동력학 해석)

  • O, Se-Hun
    • 연구논문집
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    • s.22
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    • pp.21-26
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    • 1992
  • Dynamic analysis is important in structural design of SCARA or articulated type industrial robots and is' usually done to main three axes. In this paper, robot arm dynamics was analyzed using FBD(free body diagram). Though the proposed scheme becomes complex as DOF(degree of freedom)increases, it allows to see types and directions of forces and moments acting on the body. Therefore, the strength analysis of robot arm can be done relatively easy in a case of either closed or open loop chain. This method can be used for obtaining dynamic simulation at off-line programming system and calculating required torques at joints at on-line system.

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A Theoretical Investigation on the Generation of Strength in Staple Yarns

  • Ghosh Anindya
    • Fibers and Polymers
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    • v.7 no.3
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    • pp.310-316
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    • 2006
  • In this article, an attempt has been made to explain the failure mechanism of spun yams. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yam, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yam rupture in its weakest link. A simple mathematical model for the tenacity of spun yams has been proposed. The model is based on the translation of fibre bundle tenacity into the yam tenacity.

Exploring the Movements of Chinese Free Independent Travelers in the U.S.: A Social Network Analysis Approach

  • Lin Li;Yoonjae Nam;Sung-Byung Yang
    • Asia pacific journal of information systems
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    • v.29 no.3
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    • pp.448-467
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    • 2019
  • In a new age of smart tourism, free independent travelers (FITs) choose their travel routes in a more diversified and less predictable way with the aid of smart services. This paper focuses on the movements of Chinese outbound FITs in the U.S. in the year of 2018. 110 places to visit (destinations) extracted from 122 travel routes recommendations on Qyer.com, a major online travel community in China, are analyzed with social network analysis (SNA). Based on the results of SNA, employing degree centrality, eigenvector centrality, betweenness centrality, network visualization, and cluster diagram methods, some preferred cities and natural attractions outside city centers (i.e., New York City (NYC), Los Angeles, San Francisco, Washington D.C., and Niagara Falls) are identified. Moreover, it is found that NYC in the East and Los Angeles in the West play a major role in the movements of Chinese FITs. This study contributes to the body of knowledge on tourist destination movements and provides valuable implications for smart service development in the tourism and hospitality industry.

Issey Miyake fashion's fold characteristics through fold architecture (Fold 건축 특성 분석에 따른 Issey Miyake 패션의 Fold 특성)

  • Seo, Meehee;Yoon, Jung-A;Lee, Younhee
    • The Research Journal of the Costume Culture
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    • v.23 no.5
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    • pp.861-875
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    • 2015
  • This study examines the formative characteristics of Fold architecture and how its properties are shown in the fashion of the modern work of Issey Miyake through analysis. In this research, the Fold classification criteria for analysis features that appeared in Issey Miyake fashion features were established through research literature on Fold architecture and leading research. Empirical data collection was conducted for Issey Miyake's work and collection by collecting photo materials, and design concepts and the results are analyzed in terms of features. Study ranges of Issey Miyake's creative design development are Pleats Please, A-POC, 132.5 project, and collections from 2000 to 2014. The conclusion is as follows. First, design concepts presented in the Issey Miyake fashion features of Fold are Hybrid, topology, and uncertainty. Hybrid look for the meaning of fashion, which is the interaction between the wearer and garments. The concept of topology designs clothing, focusing on interrelationship of the body and clothing, and pays no attention to absolute size or the form of the clothing. The concept of uncertainty is an uncertain form that is infinitely expandable because all the elements have openness and uncertainty due to the determined incomplete state by the creator. Second, in the results presented in the Issey Miyake fashion features is the destruction of the boundary and diagram form. The destruction of the boundary is free from traditional clothing. The diagram form is a geometric form which does not create a Dart or Princess line.

Obtaining Design Characteristics of Lever-linked Roberval Mechanism through Weighing Method (무게측정방식에 따른 Lever-linked Roberval Mechanism의 설계특성)

  • An, Ji Yun;Ahn, Jung Hwan;Lee, Gil Seung;Kim, Hwa Young
    • Journal of Sensor Science and Technology
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    • v.29 no.5
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    • pp.336-341
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    • 2020
  • The deflection and null balance methods are used for precision force measurement in the precision industry. Since both methods are based on deformation, the performance of the load cell mechanism is important. In this study, the design variables were obtained via the free body diagram of a lever-linked Roberval mechanism (combined with a flexible hinge link and a Roberval mechanism), and the design characteristics were analyzed according to the weight method. Based on the design characteristics, the optimal design was conducted according to the weight method and FEM was used to verify its reliability.

Geometrical Analysis on Parts of Load Limit Valve for Static Structural Test of Aerospace Flight Vehicles (항공우주 비행체 정적구조시험용 하중제한밸브 부품 형상 분석)

  • Shim, Jae-Yeul
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.9
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    • pp.607-616
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    • 2019
  • Free body diagram analysis is done for key parts of pilot stage of LLV (Load Limit Valve) which is used to protect overload for static structural test of aerospace flight vehicle. It is shown through the analysis that diameter ratio($D_2)^{ten}/D_2)^{comp}$) of two poppets in a pilot stage must be equal to piston area ratio($A_{comp}/A_{ten}$) of a hydraulic actuator for making a poppet open consistently at constant force applied by an actuator. The result of the analysis is verified by measuring geometries of the poppets in the four different LLVs which are corresponding to four actuators with different capacity and have been used after being imported in this laboratory. Results of "Adjuster resolution tests" with two different pilot stages show the max. deviation of Fi(actuator force in instant of opening poppet) from average Fi obtained for each turn of adjuster is 0.3KN and max. deviation of the Fi normalized by average Fi of each turn of adjuster is 3.7%. From the results, it is verified that the two pilot stages with same poppet diameter ratio make a poppet consistently open at Fis within ${\pm}3.7%$ deviation from the average Fi. The deviation is shown to be caused from frictional force of O-ring in the poppet. Additionally, design factors for poppet spring and adjuster, which are also key parts of the pilot stage, are distinguished and procedure for deciding the factors are also shown in this study.

Study on the Prediction of Lateral and Yawing Behaviors of a Leading Vehicle in a Train Collision (철도차량 충돌 시 선두차량의 횡 및 요잉 거동 예측 연구)

  • Kim, Jun Woo;Jeong, Eui Cheol;Koo, Jeong Seo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.2
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    • pp.95-101
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    • 2017
  • In this study, we derived theoretical equations for the zigzag movement of a leading vehicle, which is the most frequent behavior in train accidents, by using a simplified spring-mass model for the rolling stock. In order to solve the equations of motion, we applied the Runge-Kutta method, which is the typical numerical analysis method used for differential equations. Furthermore, the lateral displacement of the wheel-set at the wheel-rail interface was estimated using kinetic energy. In order to verify the derived equations, we compared the theoretical and simulated results under various collision conditions. The maximum relative deviations of the lateral displacements were 0.8 [%] ~ 4.7 [%] in light collisions and 0.6 [%] ~ 5.1 [%] under derailment conditions. When an accident is simulated, these theoretical equations can be used to predict the overall behavior and obtain the offset of the body-to-body link as the initial perturbation.

A Study of Iris Van Herpen Fashion from the Perspective of Deleuze's Sensory Theory (들뢰즈의 감각론의 관점으로 본 아이리스 반 헤르펜 패션에 관한 연구)

  • Song, Haein;Kim, Jinyoung
    • Journal of Fashion Business
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    • v.24 no.4
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    • pp.117-129
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    • 2020
  • Just as the name 'aesthetics' implies, the meaning of 'aisthesis' or 'sense' in Greek, is perceived as an important element in modern social design. Gilles Deleuze emphasized sensory expression over the rational side of the body, and argued for sensory theory, which is the theory of how painting produces new senses. The purpose of this study was to theoretically examine the sensory theory of Deleuze, which has given new value to the senses, apply it to analyze the body expression method shown in the Iris van Herpen collection, and derive its aesthetic characteristics. In his sensory theory, Deleuze argued that the senses can be expressed by the embodiment of force and rhythm, and one can only create art through the senses. To develop one's philosophical logic through Bacon's painting, we divided it into Hysteria, Cops sans organs, Diagram, Becoming, and Paired figures. Based on these analyses, the visualization of the senses in Iris van Herpen fashion resulted in hysteria, organ-free body, diagrams, and heterogeneity combinations. Analysis of the method of expression revealed rhythmicity, atypicality, scalability, and reproducibility as expression characteristics. Applying Deleuze's sensory theory to access experimental Iris van Herpen's fashion could confirm that there was an open system's accessibility. Deleuze's sensory theory, which has given a new value to the senses, will further help to understand modern fashion design in a wide and diverse way and discover the intrinsic value within it.

The Incipient Deformation Analysis for Plane Strain Open-Die Forging Processes with V-shaped Dies Using the Force Balance Method (힘평형법을 이용한 V-형다이 평면변형 자유형 단조공정의 초기변형 해석)

  • Lee, J.H.;Kim, B.M.
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.4
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    • pp.109-117
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    • 1993
  • Force balance method is employed to predict forging information such as forging load, tool pressure and normal stress at the surface of tangential velocity discontinuity. The incipient stages of deformation for the plane strain forging of rectangular billets in V-shaped dies of different semi-angles are analysed. To construct an approximate model for the analysis of deformation by the force balance method in the incipient deformation stages, slip-line field is used. When the deformation mode by slip-line method is the same as that by force balance method, the slip-line method and the force balance method give identical solutions. The effects of die angle, coefficient of friction, billet geometries and deforma- tion characteristics are also investigated. In order to verify the validity of force balance analysis, the rigid-plastic finite element simulation for the various forgig parameters are performed and performed and find to be in good agreement.

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A Study on Prediction of Overriding Behavior Leading Vehicle in Train Collision (철도차량 충돌시 선두차량의 타고오름량 예측 연구)

  • Kim, Jun Woo;Koo, Jeong Seo;Kim, Geo Young;Park, Jeong Pil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.8
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    • pp.711-719
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    • 2016
  • In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.