A direct modification method for strains due to non-conforming modes

Choi, Chang Koon; Chung, Keun-Young; lee, tae-yeol

doi:10.12989/sem.2001.11.3.325

Cited by 13 publications

(8 citation statements)

References 12 publications

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“…2 Modeling of track-bridge system with various finite elements beam elements on a two-parameter elastic foundation which is capable of representing the characteristics of practical foundations. The bridge deck is modeled by variable-node nonconforming flat shell (NFS) elements with drilling DOF, which shows high performance in the numerical examples of general plate/shell structures and folded plate structures in the previous study [26]. The nonconforming flat shell element is formulated by a linear combination of the nonconforming membrane element with drilling DOF and the nonconforming plate bending element.…”

Section: Analytical Modeling Approach For a Railway Bridgementioning

confidence: 99%

Reliability analysis for the uncertainties in vehicle and high-speed railway bridge system based on an improved response surface method for nonlinear limit states

2009

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The paper deals with the reliability analysis for the high-speed railway bridge systems. Although the bridge-vehicle interactive system has much more uncertainties in the resistance and loads of trains moving at very high speed compared with static structural analysis, little concern has been engaged to identify which random variable has to be considered in the probabilistic analysis, or what criteria should be selected to determine the probabilistic safety or serviceability. The considered design parameters thus involve uncertainties in stiffness, moment of inertia, damping ratio of primary suspension in terms of load, geometry of girders and slabs, and the mechanical properties of girders in terms of resistance. The considered limit states embrace the safety of trains and comfort of passengers, and the acceptability criteria are based on UIC code. For evaluating the reliability of the timedependent nonlinear behavior of complex structures, an improved Response Surface Method (RSM) is developed. An adaptive technique and a weight matrix are utilized as an optimizing technique that accelerates the convergence in the reliability analysis. The results of improved RSM, compared with the basic and adaptive RSM, are verified with the improved convergence to the exact solution. The bridge response is analyzed using a new three-dimensional finite element model of high-speed train-bridge interactions. The track structures are idealized using beam elements with the offset of beam nodes and beams on a twoparameter elastic foundation. The vehicle model developed for a 300 km/h train is employed. The calculated reliabilities for performance of the considered bridges and the passenger comfort on board of highspeed trains are compared to the conventional safety indices. The results of this study allow identifying the quantification of uncertainties that can control quality of the high-speed train service.Keywords Reliability analysis · High-speed railway bridge · Vehicle-bridge interaction analysis · Variable-node finite element · Improved response surface method 2 T. Cho et al.

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Section: Analytical Modeling Approach For a Railway Bridgementioning

confidence: 99%

Reliability analysis for the uncertainties in vehicle and high-speed railway bridge system based on an improved response surface method for nonlinear limit states

2009

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“…To solve this problem, Choi et al [16] used a direct modiÿcation method. This method not only satisÿes the requirement for an element with general non-conforming modes to pass the patch test, but also requires less computational time comparing to B-bar method [15].…”

Section: Direct Modiÿcation For Strains Due To Non-conforming Modesmentioning

confidence: 99%

“…This remedy guarantees that the element always pass the patch test for various types of non-conforming modes, but the correction matrix needs to be computed at every integration points. Recently, Choi et al [16] suggested direct modiÿcation method with the correction constants calculated analytically which set the non-conforming modes free from patch test failure. Choi et al [16] showed that in addition to the basic non-conforming modes, the use of additional higher order non-conforming modes is favorable for further improvement of behaviours of the distorted 8-node hexahedral elements.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Choi et al [16] suggested direct modiÿcation method with the correction constants calculated analytically which set the non-conforming modes free from patch test failure. Choi et al [16] showed that in addition to the basic non-conforming modes, the use of additional higher order non-conforming modes is favorable for further improvement of behaviours of the distorted 8-node hexahedral elements. Their elements, however, did not have the rotational degrees of freedom at nodes.…”

Section: Introductionmentioning

confidence: 99%

“…The main objective of this paper is to show the e ectiveness of the direct modiÿcation method in a uniÿed framework to formulate both membrane and hexahedral elements with drilling (or rotational) degrees of freedom. To improve the element behaviours, the non-conforming modes are added to the original displacement ÿelds and the direct modiÿcation method [16] is incorporated in the formulation. Also, the selective and modiÿed integration scheme is used in the element formulation.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Direct modification for non‐conforming elements with drilling DOF

Choi

lee

Chung

2002

Numerical Meth Engineering

Self Cite

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SUMMARYA uniÿed approach to eliminate the undesirable lockings in distorted meshes for both non-conforming quadrilateral membrane and hexahedral elements with drilling (or rotational) degrees of freedom is presented. The direct modiÿcation scheme is utilized in the formulation of non-conforming modes to improve the general behaviour of isoparametric-based elements. It is shown that the direct modiÿcation is very e ective in eliminating the locking and this improvement of element behaviour may be doubled if the selective integration scheme is used simultaneously. To verify the validity of elements formulated by the proposed schemes and to evaluate their e ectiveness, several numerical tests are carried out. The combined use of additional non-conforming modes with the direct modiÿcation method and the selective integration technique plays an important role to improve the behaviour of elements, especially for distorted mesh cases. Test results also show that the results for both non-conforming quadrilateral membrane and hexahedral elements obtained by the proposed schemes are equally satisfactory.

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A Review on Membrane Finite Elements with Drilling Degree of Freedom

Boutagouga

2020

Arch Computat Methods Eng

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A direct modification method for strains due to non-conforming modes

Cited by 13 publications

References 12 publications

Reliability analysis for the uncertainties in vehicle and high-speed railway bridge system based on an improved response surface method for nonlinear limit states

Reliability analysis for the uncertainties in vehicle and high-speed railway bridge system based on an improved response surface method for nonlinear limit states

Direct modification for non‐conforming elements with drilling DOF

A Review on Membrane Finite Elements with Drilling Degree of Freedom

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