• Title/Summary/Keyword: modified CFM

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Simplified sequential construction analysis of buildings with the new proposed method

  • Afshari, Mohammad Jalilzadeh;Kheyroddin, Ali;Gholhaki, Majid
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.77-88
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    • 2017
  • Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

A Study on Application and Validation of the Coherent Flamelet Model in Counterflow Turbulent Premixed Combustion (대향류 예혼합 난류 연소 유동에서의 Coherent Flamelet Model 적용 및 검증에 관한 연구)

  • Choi, C.R.;Huh, K.Y.
    • Journal of the Korean Society of Combustion
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    • v.1 no.2
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    • pp.51-58
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    • 1996
  • The coherent flamelet model(CFM) is applied to symmetric counterflow turbulent premixed flames. The flame source term is set proportional to the turbulence intensity to reproduce the experimental correlation of Abdel-Gayed et al. for the turbulent burning velocity. Flame quenching by the turbulent rate of strain is modeled by an additional multiplication factor to the flame source term. A modified form of CFM is employed to consider coexistence of burned and unburned premixture with ambient air. The predicted flame position and turbulent flow field coincide well with the experimental data of Kostiuk et al., although there is some discrepancy in the radial rms velocity component and integral length scale near the symmetric plane.

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