• Title/Summary/Keyword: variable.elastic foundation

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Size-dependent free vibration of coated functionally graded graphene reinforced nanoplates rested on viscoelastic medium

  • Ali Alnujaie;Ahmed A. Daikh;Mofareh H. Ghazwani;Amr E. Assie;Mohamed A Eltaher
    • Advances in nano research
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    • v.17 no.2
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    • pp.181-195
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    • 2024
  • This study introduces a novel functionally graded material model, termed the "Coated Functionally Graded Graphene-Reinforced Composite (FG GRC)" model, for investigating the free vibration response of plates, highlighting its potential to advance the understanding and application of material property variations in structural engineering. Two types of coated FG GRC plates are examined: Hardcore and Softcore, and five distribution patterns are proposed, namely FG-A, FG-B, FG-C, FG-D, and FG-E. A modified displacement field is proposed based on the higher-order shear deformation theory, effectively reducing the number of variables from five to four while accurately accounting for shear deformation effects. To solve the equations of motion, an analytical solution based on the Galerkin approach was developed for FG GRC plates resting on a viscoelastic Winkler/Pasternak foundation, applicable to various boundary conditions. A comprehensive parametric analysis elucidates the impact of multiple factors on the fundamental frequencies. These factors encompass the types and distribution patterns of the coated FG GRC plates, gradient material distribution, porosities, nonlocal length scale parameter, gradient material scale parameter, nanoplate geometry, and variations in the elastic foundation. Our theoretical research aims to overcome the inherent challenges in modeling structures, providing a robust alternative to experimental analyses of the mechanical behavior of complex structures.

A Study on the Load Distribution Ratio and Axial Stiffness on Existing and Reinforcing-Pile in Vertical Extension Remodeling (수직증축시 기존말뚝과 보강말뚝의 하중분담율 및 축강성 분석)

  • Jeong, Sang-Seom;Cho, Hyun-Cheol
    • Journal of the Korean Geotechnical Society
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    • v.35 no.1
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    • pp.17-30
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    • 2019
  • This study presents the application of the numerical and analytical technique to simulate the Load Distribution Ratio (LDR) and to define axial stiffness on reinforcing pile foundation ($K_{vr}$) in vertical extension remodeling structure. The main objective of this study was to investigate the LDR between existing piles and reinforcing piles. Therefore, to analyze the LDR, 3D FEM analysis was performed as variable for elastic modulus, pile end-bearing condition, raft contacts, and relative position of reinforcing pile in a group. Also, using the axial stiffness ($K_{ve}$) of existing piles, the axial stiffness of reinforcing pile was defined by 3D approximate computer-based method, YSPR (Yonsei Piled Raft). In addition $K_{vr}$ was defined by reducing the $K_{ve}$considering the degradation of the existing piles.