Turan, Muhittin; Adiyaman, Gokhan

A new type of functionally graded material (FGM) with material properties varying in two or three directions is needed to obtain materials with better mechanical properties and high-temperature resistance for use in the military, aerospace, automotive, and engineering structures. Considering the porosity that occurs during the production of these materials, it has become necessary to examine the free vibration and buckling behaviors. Therefore, this study investigated free vibration and buckling analysis of porous two-directional functionally graded (2D FG) beams subject to various boundary conditions. A high-order finite element based on parabolic shear deformation theory (PSDT) is proposed to solve this problem. Three types of porosity distributions were used in the study (FGP-1, FGP-2, and FGP-3). The governing equations are derived from Lagrange’s principle. The material change in the beam volume in both directions is defined by a power-law rule. The dimensionless fundamental frequencies and critical buckling loads are obtained for various boundary conditions, gradation exponents (px, pz), porosity coefficient (e), porosity distribution, and slenderness (L/h). The numerical results obtained with the proposed higher-order finite element are compatible with the literature.

AtıfScopus47·WoS44·OpenAlex40

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Düzgün, Oğuz Akın; Hatipoğlu, Yavuz Selim

Purpose: In this study, the effective damping coefficient of the fluid viscous dampers (FVDs) used for coupling two adjacent multi-story frames was investigated, considering soil-structure interaction (SSI) effects under seismic excitation. Methods: A numerical procedure was employed to obtain the dynamic response of the interconnected frames-soil system. The two-dimensional (2D) finite elements were used for the numerical treatment of the adjacent frames and soil region. Viscous boundary conditions were used as special non-reflecting boundaries on the edges of finite soil region. Five different damping coefficients of FVDs are considered to determine the effective damping coefficient. The effective damping coefficient of FVDs was determined by comparing the results from coupled frames with those of the uncoupled frames. Results: The results showed that the most affecting parameter on the system response was found to be soil type. It was also found that the sufficient damping coefficient of the viscous damper is equal to 1 × 105 N s/m for minimum response. Conclusion: When the effective damping coefficient of the FVDs was provided, the maximum values of the roof displacements, the roof accelerations, and the base shear forces are found to decrease by more than 40%.

AtıfScopus3·WoS2·OpenAlex4

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