• 제목/요약/키워드: general loading condition

검색결과 98건 처리시간 0.029초

Inelastic lateral-torsional buckling strengths of stepped I-beams subjected to general loading condition

  • Park, Jong Sup;Park, Yi Seul
    • Structural Engineering and Mechanics
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    • 제48권2호
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    • pp.275-289
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    • 2013
  • The cross sections of multi-span beams are sometimes suddenly increased at the interior support of continuous beams to resist high negative moment. An earlier study on elastic lateral torsional buckling of stepped beams was conducted to propose new design equations. This research aims to continue the earlier study by considering the effect of inelastic buckling of stepped beams subjected to pure bending and general loading condition. A three-dimensional finite element-program ABAQUS and a statistical program MINITAB were used in the development of new design equations. The inelastic lateral torsional buckling strengths of 36 and 27 models for singly and doubly stepped beams, respectively, were investigated. The general loading condition consists of 15 loading cases based on the number of inflection point within the unbraced length of the stepped beams. The combined effects of residual stresses and geometrical imperfection were also considered to evaluate the inelastic buckling strengths. The proposed equations in this study will definitely improve current design methods for the inelastic lateral-torsional buckling of stepped beams and will increase efficiency in building and bridge design.

일반 대기 네트워크에 있어서 시스템 설계애 관한 연구 (Reducing Congestion General Queuing Networks)

  • Kim, Sung-Chul
    • 한국경영과학회지
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    • 제14권2호
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    • pp.87-96
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    • 1989
  • We develop an algorithm to determine the optimal loading policy, which minimizes the congestion in general queueing networks with variable stations. Under more specified condition, majorization and arrangement ordering are established to compare, respectivity, various loading and assignment policies. Implications of results are also discussed.

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동하중조건에서의 다중격자 다중차원법을 이용한 점접촉 탄성유체윤활 유막두께연구 (Study of the Film Thickness in the Elastohydrodynamic Lubrication of Circular Contact under the Dynamic Loading Condition with Multigrid Multilevel Method)

  • 장시열
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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    • pp.218-223
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    • 2001
  • Many research of elastohydrodynamic lubrication (EHL) has been performed under the condition of steady state loding. However, mechanical elements undergo severe high loads that are fluctuating in general. Conventional numerical method for the circular contact of EHL study has a difficulty in converging the film pressure and thickness especially in high load of steady state. In this work, multigrid multilevel method expels the convergence problem under the condition of high load and very stable convergence is obtained under the dynamic loading condition over 1.0GPa. Several results of dynamic loading condition are shown and compared with those of steady state condition.

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Adaptive 방법을 이용한 관재액압성형조건 도출 (Derivation of Loading Conditions for Tube Hydroforming Process using Adaptive Method)

  • 허성찬;김정;강범수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회A
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    • pp.642-647
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    • 2007
  • Determination of loading conditions for tube hydroforming(THF) process that implies an amount of the increment in axial feeding and internal pressure for each step is one of the most important constituents at the process design level. On account of the fact that those design factors mentioned above are imposed simultaneously during the process, suitable loading conditions are required to obtain robust products without any failure such as buckling, necking, bursting and so on. In which, especially, bursting is well known as the most frequently occurred failure in general THF process. In this study, therefore, determination of the loading condition based on the adaptive method was carried out to obtain safe loading paths. In addition, forming limit curves are applied to evaluate the derived loading conditions by using the simulation results. Consequently, it is found that described method in this study for THF process design is useful and has a feasibility.

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복수의 서버를 갖는 작업장으로 구성된 일반대기네트워크에 있어서 균형과 불균형부하 (Balancing / Unbalancing in General Queueing Networks with Multi-Server Stations)

  • 김성철
    • 대한산업공학회지
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    • 제21권2호
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    • pp.289-298
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    • 1995
  • We consider a general queueing network with multi-server stations. The stations are under heavy traffics or moderate variable conditions. We develope an algorithm to determine the optimal loading policy, which minimizes the congestion in a network. Under more specified condition, majorization and arrangement orderings are established to compare, respectively, various loading and assignment policies. Implications of results are also discussed.

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Multiple-loading condition을 고려한 구조체의 위상학적 최적화 (Topological Structural Optimization under Multiple-Loading Conditions)

  • 박재형;홍순조;이리형
    • 전산구조공학
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    • 제9권3호
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    • pp.179-186
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    • 1996
  • 본 연구에서는 구조체의 위상학적 최적화를 위한 비선형 formulation(NLP)가 개발, 검토되었다. 이 NLP는 multiple-loading하에서 임의의 오브젝티브 함수, 응력, 변위 제약조건들을 쉽게 다룰 수가 있다. 또한 이 NLP는 해석과 최적화 디자인을 동시에 실시함으로써 요소 사이즈가 영으로 접근함에 따른 강성 매트릭스의 singularity를 피할 수 있다. 즉, 평형 방정식을 등제약조건으로 치환함으로써 강성 매트릭스 그 자체나 그의 역매트릭스를 구할 필요도 없어진다. 이 NLP는 multiple-loading conditon하에서 테스트되었으며, 이를 통해 이 NLP가 다양한 제약조건하에서 강력하게 작용함이 입증되었다.

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에너지 등고선을 이용한 고주파 가진 조건들에 따른 선형 시스템의 피로 손상도 분석 (Analysis of Spectral Fatigue Damage of Linear Elastic Systems with Different High Cyclic Loading Cases using Energy Isocline)

  • 신성영;김찬중
    • 한국소음진동공학회논문집
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    • 제24권11호
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    • pp.840-845
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    • 2014
  • Vibration profiles consist of two kinds of pattern, random and harmonic, at general engineering problems and the detailed vibration test mode of a target system is decided by the spectral condition that is exposed under operation. In moving mobility, random responses come generally from road source; whereas the harmonic responses are triggered from rotating machinery parts, such as combustion engine or drive shaft. Different spectral input may accumulate different damage in frequency domain since the accumulated fatigue damage dependent on the pattern of input spectrum in high cyclic loading condition. To evaluate the sensitivity of spectral damage according to different loading conditions, a linear elastic system is introduced to conduct a uniaxial vibration testing. Measured data, acceleration and strain, is analyzed using energy isocline function and then, the calculated fatigue damage is compared by different loading cases, random and harmonic.

임의 경계조건을 가진 원통셸 구조의 유체영향계수 해석 (An Analysis on the Fluid-Loading Coefficients of Cylindrical Shell Structure With Arbitrary end Conditions)

  • 전재진;정우진
    • 소음진동
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    • 제6권3호
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    • pp.297-303
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    • 1996
  • The general approach using sine series expansions was represented to evaluate the radiation loading from a vibrating surface on a simply supported cylinder. In this paper, the fluid-loading coefficients (radiation impedance) for a submerged finite cylindrical shell with an arbitrary end condition are defined and evaluated. The vibrations of cylindrical shell are expressed by using cosine series expansions to analyze the radiation impedance for a finite cylindrical shell. It is possible to represent the displacements at both ends of cylindrical shell in comparison with sine series. The direct and cross modal components of fluid-loading coefficients are shown and the validity of cosine series expansions are verified from the results of numerical computations. This approach and results are directly applicable in the analysis of sound radiation from subemerged finite cylindrical shell with arbitrary end conditions.

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항공기 시뮬레이터 조종력 제어시스템의 견실 $\mu$-제어기 설계 (Robust $\mu$-Controller design for Control Loading System of Flight Simulator)

  • 방경호
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 1998년도 추계종합학술대회 논문집
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    • pp.405-408
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    • 1998
  • Generally, the principle function of simulator control loading system is to provide the pilot or student with the "feel" of the actual aircraft flight control systems during flight, taxing, and in malfunction. Flight control "feel" is the resistance felt by the pilot when moving a control stick or pedal, coupled with the amount of control surface deflection, and hence aircraft response, resulting from the input. Therefore, the control loading servo must be capable of performing to some general list of requirements derived from real aircraft control forces. In this paper, we deal with a $\mu-controller$ design for a control loading system of the flight simulator. For this, we derive a frequency response of the hydraulic system from the identification data and then design a controller using a $\mu-synthesis$ method. Under the same condition of simulation, $\mu-controller$ provides the superior performance than PID controller.than PID controller.

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Buckling of thin-walled members analyzed by Mindlin-Reissner finite strip

  • Cuong, Bui H.
    • Structural Engineering and Mechanics
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    • 제48권1호
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    • pp.77-91
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    • 2013
  • The paper presents the formulation of 3-nodal line semi-analytical Mindlin-Reissner finite strip in the buckling analysis of thin-walled members, which are subjected to arbitrary loads. The finite strip is simply supported in two opposite edges. The general loading and in-plane rotation techniques are used to develop this finite strip. The linear stiffness matrix and the geometric stiffness matrix of the finite strip are given in explicit forms. To validate the proposed model and study its performance, numerical examples of some thin-walled sections have been performed and the results obtained have been compared with finite element models and the published ones.