• Title/Summary/Keyword: transverse forces

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Ice forces acting on towed ship in level ice with straight drift. Part II: Numerical simulation

  • Zhou, Li;Chuang, Zhenju;Bai, Xu
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.10 no.2
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    • pp.119-128
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    • 2018
  • A numerical method is proposed to simulate level ice interaction with ship in transverse and longitudinal directions in time domain. A novel method is proposed to simulate non-symmetric transverse force in a stochastic way. On the basis of observations from the model tests, the simulation of longitudinal force combines the ice bending force acting on the waterline, submersion force below the waterline and ice friction forces caused by transverse force and ice floes rotation amidships. In the simulations the ship was fixed and towed through an intact ice sheet at a certain speed. The setup of the numerical simulation is similar to the ice tank setup as much as possible. The simulated results are compared with model tests data and the results show good agreement with the measurement.

Mechanical Integrity Evaluation on the Degraded Cladding Tube of Spent Nuclear Fuel Under Axial and Bending Loads During Transportation

  • Lee, Seong-Ki;Lee, Dong-Hyo;Park, Joon-Kyoo;Kim, Jae-Hoon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.4
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    • pp.491-501
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    • 2021
  • This paper aims to evaluate the mechanical integrity for Spent Nuclear Fuel (SNF) cladding under lateral loads during transportation. The evaluation process requires a conservative consideration of the degradation conditions of SNF cladding, especially the hydride effect, which reduces the ductility of the cladding. The dynamic forces occurring during the drop event are pinch force, axial force and bending moment. Among those forces, axial force and bending moment can induce transverse tearing of cladding. Our assessment of 14 × 14 PWR SNF was performed using finite element analysis considering SNF characteristics. We also considered the probabilistic procedures with a Monte Carlo method and a reliability evaluation. The evaluation results revealed that there was no probability of damage under normal conditions, and that under accident conditions the probability was small for transverse failure mode.

Transverse and longitudinal partial interaction in composite bolted side-plated reinforced-concrete beams

  • Oehlers, D.J.;Nguyen, N.T.;Ahmed, M.;Bradford, M.A.
    • Structural Engineering and Mechanics
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    • v.5 no.5
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    • pp.553-563
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    • 1997
  • A procedure is being developed for bolting plates to the sides of existing reinforced concrete beams to strengthen and stiffen them. Unlike standard composite steel and concrete beams in which there is longitudinal-partial-interaction at the steel/concrete interface (that is slip along the length of the beam), composite bolted side-plated reinforced-concrete beams are unique in that they also exhibit transverse-partial-interaction, that is slip transverse to the length of the beam. In this work, the fundamental mathematical models for transverse-partial-interaction and its interaction with longitudinal-partial-interaction are developed. The fundamental models are then further developed to determine the number of connectors required to resist the transverse forces and to limit the degree of transverse-partial-interaction in bolted side-plated reinforced concrete beams.

Study on the Structural Reinforcements for the Transverse Vibration of Ship's Main Engine (선박 주기관 횡진동 구조보강 검토)

  • Im, Hong-Il;Shin, Sang-Hoon
    • Special Issue of the Society of Naval Architects of Korea
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    • 2013.12a
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    • pp.55-59
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    • 2013
  • Transverse vibrations of ship's aft end and deckhouse among the various modes of hull structures are induced mainly by transverse exciting forces and moments of main engine such as ${\times}$ and h-moment. Avoidance of resonance should be made in a intial design stage in case there is a prediction for resonance between main engine and transverse modes of deckhouse. This study shows a case of change in type of main engine from 12 cylinders to 10 without modification of hull structures in engine room requested by a shipowner of 8,600 TEU class container carrier and proposes a guide to the effective ways of structural arrangement for avoiding resonance between transverse exciting force and surrounding structures of main engine in engine room through case studies.

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Evaluation of the delamination strengths in differently processed practical Ag-stabilized REBCO CC tapes under transverse loading

  • Diaz, Mark A.;Shin, Hyung-Seop;Ha, Hongsoo;Oh, Sang-Soo
    • Progress in Superconductivity and Cryogenics
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    • v.21 no.4
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    • pp.34-38
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    • 2019
  • Multilayered high-temperature superconductor coated conductor (CC) tapes are used in an extensive range of applications and are exposed to many stresses such as hoop stress, radial/transverse tensile stress under large Lorentz forces, and thermal stress while cooling if thermal expansion properties differ. Loads induced transversely at the tape surface inevitably create delamination phenomena in the multilayered CC tapes. Thus, delamination behaviors of CC tapes along the c-axis under transverse loading conditions, which can vary based on manufacturing process and constituent layers, must be characterized for applications. The anvil test method was used to mechanically investigate the delamination characteristics of various commercially available Ag-stabilized CC tapes at room temperature and 77 K, finding superior strength at the latter. The wide variations found depended on tape structure and fabrication technique. Fractographic morphologies of delaminated tapes supported the findings under transverse loading conditions.

The assessment of Safe Navigation Regarding Hydrodynamic forces between ships in Restricted Waterways

  • Lee, Chun-Ki;Yun, Jong-Hwui;Yoon, Jeom-Dong
    • Proceedings of KOSOMES biannual meeting
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    • 2006.11a
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    • pp.143-149
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    • 2006
  • This paper is primarily focused on the safe navigation between overtaking and overtaken vesselsin restricted waterways under the external forces, such as wind and current. The maneuvering simulation between two ships was conducted to find an appropriate safe speed and distance, which is required to avoid collision. From the viewpoint of marine safety, a greater transversedistance between two ships is more needed for the smaller vessel. Regardless of external forces, the smaller vessel will get a greater effect of hydrodynamic forces than the higher one. In the case of close navigation between ships under the forces of wind and current, the vessel moving at a lower speed is potentially hazardous because the rudder force of the lower speed vessel is not sufficient for steady-state course-keeping, compared to that of the higher speed vessel.

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Numerical Simulations for Suppressing Transverse Vibration of a very Flexible Rotating Disk using Air Bearing Concept (고속 회전 유연 디스크의 진동 저감용 공기 베어링 해석)

  • Lee Sung-ho;Rhim Yoon-chul
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2004.11a
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    • pp.175-185
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    • 2004
  • Rotating disks are used in various machines such as data storage device, gyroscope, circular saw, etc. Transverse vibration of a rotating disk is very important for the performance of these machines. This work proposes a method to suppress transverse vibration of a very flexible rotating disk in non-contacting manner. A system considered in this study is a very flexible rotating disk with a thrust bearing pad which is located underneath the rotating disk. The pressure force generated in the gap between the rotating disk and the thrust pad pushes the rotating disk in the direction of axis of rotation while the centrifugal force and the elastic recovery force push the rotating disk in reverse direction. The balance between these forces suppresses the transverse vibration of the rotating disk. A coupled disk-fluid system is analyzed numerically. The finite element method is used to compute the pressure distribution between the thrust pad and the rotating disk while the finite difference method is used to compute the transverse vibration of a rotating disk. Results show that the transverse vibration of the rotating disk can be suppressed effectively for certain combination of air bearing and operating parameters.

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Calculation of a reference force for feedrate scheduling using the FEM analysis of a tool (엔드밀링 공구의 유한요소해석을 통한 이송속도 스케줄링의 기준 절삭력 산출)

  • 이한울;조동우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.10a
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    • pp.416-421
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    • 2004
  • Off-line feedrate scheduling is presented as the advanced technology to regulate cutting forces at the desired level through change of feedrates. In rough cutting, the feedrate scheduling aims at reducing the machining time, which is the most important factor for better productivity. Thus, the largest force which can avoid breakage of tool shank and tooth is a reference force for feedrate scheduling in rough cutting. In this paper, a calculation method of the reference cutting force for feedrate scheduling is developed. This model calculates rupture plane of tooth using the FEM analysis of a tool and computes the reference force using the transverse rupture strength of a tool. Experiments validate that the presented feedrate scheduling model reduced machining time drastically and regulate cutting forces at the reference cutting force.

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Nonlinear vibration of Mindlin plate subjected to moving forces including the effect of weight of the plate

  • Wang, Rong-Tyai;Kuo, Nai-Yi
    • Structural Engineering and Mechanics
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    • v.8 no.2
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    • pp.151-164
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    • 1999
  • The large deflection theory of the Mindlin plate and Galerkin's method are employed to examine the static responses of a plate produced by the weight of the plate, and the dynamic responses of the plate caused by the coupling effect of these static responses with a set of moving forces. Results obtained by the large deflection theory are compared with those by the small deflection theory. The results indicate that the effect of weight of the plate increases the modal frequencies of the structure. The deviations of dynamic transverse deflection and of dynamic bending moment produced by a moving concentrated force between the two theories are significant for a thin plate with a large area. Both dynamic transverse deflection and dynamic bending moment obtained by the Mindlin plate theory are greater than those by the classical plate.

Design of PM Excited Transverse Flux Linear Motor of Inner Mover Type

  • Kang Do-Hyun;Ahn Jong-Bo;Kim Ji-Won;Chang Jung-Hwan;Jung Soo-Jin
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • v.5B no.2
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    • pp.137-141
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    • 2005
  • A transverse flux, PM-exited linear motor (TFM-LM) with inner mover was designed and built. Its output power density is higher and its weight is lower than those of the conventional PM exited linear synchronous motors (PM LSM). To obtain the maximum thrust force under the given volume, the thrust force density with respect to the ratio of the slot width and the length of pole pitch is analyzed by the 3-dimension finite element method (FEM). Finally, calculated static thrust forces was compared with the experimental values. The calculated and measured performance of the transverse flux, PM-exited linear motor with inner mover revealed great potential for system improvements by reducing the mass of the linear motor. For examples, when this motor was applied to a ropeless elevator, it was possible to increase the power density by more than 400% over the conventional PM-LSM. The results of this study recommend this type of motor for the ropeless elevator or gearless direct linear driving system.