• Title/Summary/Keyword: Beam-on-spring model

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A Study on the Flexibility of Semi-Rigid Steel Frames under Lateral Loadings( II ) (횡하중을 받는 반강접 철골 골조의 유연도에 관한 연구( II ) -골조 해석모형을 중심으로-)

  • Kang, Cheol Kyu;Han, Young Cheol;Lee, Gab Jo
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4 s.29
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    • pp.121-131
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    • 1996
  • Semi-rigid frames are frames for whcih the connections joining the beam and column are neither fully rigid nor perfectly pinned. In reality, all steel frames are semi-rigid in nature as all connections exhibit a certain degree of flexibility under loads. For semi-rigid frmaed structures, it is tended to reduce more rigidity of the member for the nonlinear behavior of connections and the P-delta effects of framed structure. To predict the actual behavior of semi-rigid steel frames, a more realistic analysis methods which explicitly takes into account the effect of connection flexibility should be used. In this research, the effect of connection flexibility in the semi-rigid structure has been investigated. To predict the response of flexibility connected frames, the algorithm of semi-rigid steel frame is developed using connection model having nonlinear spring on end of beam.

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PID Force Control of a miniature robot Gripper (PID 제어기에 의한 소형 로봇용 그리퍼의 힘 제어)

  • 홍동표
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.2
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    • pp.44-49
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    • 1999
  • This paper is concerned with the theoretical and experimental study on the force conrtrol of a miniature robotic gripper. The gripper is an uniform flexible cantilever equipped with a distributed set of compact force sensor. As an actuator piezoelectric acturator, piezoelectric acturator is fixed with cupper plate at which the beam is clamped. The mathematical model of the assembled electro-mechaincal system is developed. The force sensor is described by a set of concentrated mass-spring system. The formulated equations of motion are applied to he study of a control problem where the gripper is commanded to grip an object The usefulness of the PID control technique is verified by experiment.

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Buckling Loads of Column with Rotation End Restricted by Rotational Spring (단부회전이 회전스프링으로 제약받는 기둥의 좌굴하중)

  • 김종웅;이태은;박광규;이병구
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.369-374
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    • 2001
  • This paper deals with the buckling loads of column with rotation end restricted by rotational spring. The ordinary differential equations governing the buckling loads of such column is derived as nondimensional forms, and also its boundary conditions are derived. The buckled column model is based on the classical Bemoulli-Euler beam theory. The Runge-Kutta method and Regula-Falsi method are used to perform the integration of the differential equations and to determine the eigenvalue. The numerical methods developed herein for the buckling loads of the such column are found to be efficient and reliable. It is expected that the results obtained herein can be practically utilized in the structural engineering field.

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Flutter Analysis Model Tuning of KC-100 Aircraft with the Ground Vibration Test Results (지상진동시험결과를 이용한 KC-100 항공기의 플러터 해석모델 보정)

  • Paek, Seung-Kil;Choi, Yong-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.191-195
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    • 2011
  • The airframe ground vibration tests were conducted on the KC-100 aircraft according to the regulation requirement, KAS 23.629(a)(2) and the modal characteristics for the target modes were measured. To make FE model tuning, a design sensitivity approach with engineering judgment was implemented using MSC/Nastran and Attune, a genetic algorithm based parameter optimization software. Based on the comparison between initial prediction and test results, design variables such as beam cross-sectional properties and spring stiffnesses were devised. As the results, the correlation of the FE model to the GVT results was made appropriately, meeting the goal of matching the target frequencies within 5%.

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Identification of Substructure Model by Measured Acceleration and Analysis of Its Problem (가속도계측에 의한 부분구조 모델의 설정 및 문제점 분석)

  • 신수봉;오성호;이상민
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.589-594
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    • 2003
  • The paper proposes a methodology of identifying a substructure model of an existing structure when correct sectional and material properties of the structure are not known. A substructure model is identified by estimating boundary spring constants and stiffness properties of the substructure. Both of static and modal system identification methods have been applied using responses measured at limited locations within the substructure. In defining a substructure model it is required that computed structural responses be consistent with the actual behavior of the part of the structure. Simulation studies on a continuous beam structure and an application to an actual bridge have been carried with static and modal responses. The results and associated problems are discussed in the paper

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A Study on Crashworthiness for Underframe of Motorized Trailer of High Speed Train (고속전철 동력객차 언더프레임에 대한 충돌특성 연구)

  • 김헌영;김상범;한재형
    • Proceedings of the KSR Conference
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    • 1998.05a
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    • pp.385-392
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    • 1998
  • Train crashes involve complex interaction between deformable bodies in multiple collisions. The purpose of this study is to suggest the effective analytical procedure using simple model for the crashworthiness of motorized trailer of high speed train. The simple model, with very short modeling time and reduced computation time was adopted to extract the global behaviour and to perform a pre-optimization of the considered structure. Firstly, various types of crash events are investigated and the conditions for numerical simulation are defined. The simple model, using the beam and non-linear spring element, and shell element model are used to evaluated energy absorption and deformation mechanism in analyses. And aluminum is applied to real model after verification with square tube analyses. Finally, loading path and energy absorption of main components are evaluated. The analyses are aimed to ensure the crashworthiness design of high speed train.

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Free Vibrations of Tapered Beams with General Boundary Condition at One End and Mass at the Other End (일단은 일반적인 지지조건을 갖고 타단은 집중질량을 갖는 변단면 보의 자유진동)

  • 오상진;이병구;이태은
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.493-500
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    • 2001
  • The purpose of this paper is to investigate the natural frequencies and mode shapes of tapered beams with general boundary condition(translational and rotational elastic support) at one end and carrying a tip mass with translational elastic support at the other end. The beam model is based on the classical Bernoulli-Euler beam theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibrations of linearly tapered beams is solved numerically using the corresponding boundary conditions. Numerical results are compared with existing solutions by other methods for cases in which they are available. The lowest three natural frequencies and the corresponding mode shapes are calculated over a wide range of section ratio, dimensionless spring constant, and mass ratio.

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Dynamic Behaviour of Pile Foundation with Scour (세굴을 고려한 말뚝기초의 동적 거동분석)

  • 김정환;허택영;박용명
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.55-62
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    • 2003
  • This study considered the effect of scour depth on the behaviour of pile foundation of bridge structure under seismic excitation. The numerical model was composed of the superstructure, pile foundation and soil. The superstructure and pile was modeled by beam elements and soil was by spring elements. The pile head and concrete footing was considered as hinge and rigid connected situation, respectively. A toro-gap element was used to model the expansion joint of superstructure. Nonlinear dynamic analysis was carried out on the constructed model. It was acknowledged that the steel pile become to yield after the scour depth reached about 2.0m.

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Experimental and analytical investigation of steel beams rehabilitated using GFRP sheets

  • El Damatty, A.A.;Abushagur, M.;Youssef, M.A.
    • Steel and Composite Structures
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    • v.3 no.6
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    • pp.421-438
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    • 2003
  • Aging and deterioration of existing steel structures necessitate the development of simple and efficient rehabilitation techniques. The current study investigates a methodology to enhance the flexural capacity of steel beams by bonding Glass Fibre Reinforced Plastic (GFRP) sheets to their flanges. A heavy duty adhesive, tested in a previous study is used to bond the steel and the GFRP sheet. In addition to its ease of application, the GFRP sheet provides a protective layer that prevents future corrosion of the steel section. The study reports the results of bending tests conducted on a W-shaped steel beam before and after rehabilitation using GFRP sheets. Enhancement in the moment capacity of the beam due to bonding GFRP sheet is determined from the test results. A closed form analytical model that can predict the yield moment as well as the stresses induced in the adhesive and the GFRP sheets of rehabilitated steel beam is developed. A detailed finite element analysis for the tested specimens is also conducted in this paper. The steel web and flanges as well as the GFRP sheets are simulated using three-dimensional brick elements. The shear and peel stiffness of the adhesive are modeled as equivalent linear spring systems. The analytical and experimental results indicate that a significant enhancement in the ultimate capacity of the steel beam is achieved using the proposed technique. The finite element analysis is employed to describe in detail the profile of stresses and strains that develop in the rehabilitated steel beam.

Seismic Performance Evaluation of Existing Low-rise RC Frames with Non-seismic Detail (비내진상세를 가지는 기존 저층 철근콘크리트 골조의 내진거동평가)

  • Kim, Kyung Min;Lee, Sang Ho;Oh, Sang Hoon
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.3
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    • pp.97-105
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    • 2013
  • In this paper, the a static experiment of on two reinforced concrete (RC) frame sub-assemblages was conducted to evaluate the seismic behaviors of existing RC frames that were not designed to support a seismic load. The specimens were a one span and actual-sized. One of them had two columns with the same stiffness, but the other had two columns with different stiffness values. As Regarding the test results, lots of many cracks occurred on the surfaces of the columns and beam-column joints for the two specimens, but the cover concrete splitting hardly occurred was minimal until the test ends. In the case of the specimen with the same stiffness offor the two columns, the flexural collapse of the left-side column occurred. However, in the case of the specimen with different stiffness values for of the two columns, the beam-column joint finally collapsed, even though the shear strength of the joint was designed to be strong enough to support the lateral collapse load. The nonlinear Nonlinear static analysis of the two specimens was also conducted using the uniaxial spring model, and the analytical results successfully simulated the nonlinear behaviour of the specimens in accordance with the test results.