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Abbas Rastgoo - One of the best experts on this subject based on the ideXlab platform.

  • An Analytical Model for Free Vibration Analysis of Smart Annular FGM Plates Integrated with Piezoelectric Layers
    international journal of advanced design and manufacturing technology, 2011
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    In this paper, a nonlinear free vibration analysis of thin annular functionally graded (FG) Plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG Plate is presented based on Kirchhoff Plate theory. The material properties of the FGM Core Plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents and the distribution of electric potential field along the thickness direction of piezoelectric layers is simulated by a sinusoidal function such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the piezoelectric coupled FG annular Plate with those of an isotropic Core Plate. In numerical study, the emphasis is placed on investigating the effect of varying the gradient index of FG Plate on free vibration characteristics of the structure. In addition, good agreement between the results of this paper and those of finite element (FE) analyses validated the present approach. The analytical solutions and findings contribute towards a simplified model for the parametric study and understanding of vibration of piezoelectric-coupled FGM annular Plate.

  • FSDPT based study for vibration analysis of piezoelectric coupled annular FGM Plate
    Journal of Mechanical Science and Technology, 2009
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    The vibration behavior of a piezoelectrically actuated thick functionally graded (FG) annular Plate is studied based on first order shear deformation Plate theory (FSDPT). A consistent formulation that satisfies the Maxwell static electricity equation is presented so that the full coupling effect of the piezoelectric layer on the dynamic characteristics of the annular FG Plate can be estimated based on the free vibration results. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the composite Plate with those of an isotropic Core Plate. As a special case, assuming that the material composition of Core Plate varies continuously in the direction of the thickness according to a power law distribution, a comprehensive study is conducted to show the influence of functionally graded index on the vibration behavior of smart structure. Also, the good agreement between the results of this paper and those of the finite element (FE) analyses validates the presented approach.

  • Geometrically nonlinear vibration analysis of piezoelectrically actuated FGM Plate with an initial large deformation
    Journal of Mechanical Science and Technology, 2009
    Co-Authors: Farzad Ebrahimi, Mohammad Hassan Naei, Abbas Rastgoo
    Abstract:

    A theoretical model for geometrically nonlinear vibration analysis of piezoelectrically actuated circular Plates made of functionally grade material (FGM) is presented based on Kirchhoff’s-Love hypothesis with von-Karman type geometrical large nonlinear deformations. To determine the initial stress state and pre-vibration deformations of the smart Plate a nonlinear static problem is solved followed by adding an incremental dynamic state to the pre-vibration state. The derived governing equations of the structure are solved by exact series expansion method combined with perturbation approach. The material properties of the FGM Core Plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents. Control of the FGM Plate’s nonlinear deflections and natural frequencies using high control voltages is studied and their nonlinear effects are evaluated. Numerical results for FG Plates with various mixture of ceramic and metal are presented in dimensionless forms. In a parametric study the emphasis is placed on investigating the effect of varying the applied actuator voltage as well as gradient index of FGM Plate on vibration characteristics of the smart structure.

  • Free vibration analysis of smart annular FGM Plates integrated with piezoelectric layers
    Smart Materials and Structures, 2008
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    In this paper, a nonlinear free vibration analysis of a thin annular functionally graded (FG) Plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG Plate is presented based on Kirchhoff Plate theory. The material properties of the functionally graded Core Plate are assumed to be graded in the thickness direction according to the power law distribution in terms of the volume fractions of the constituents and the distribution of the electric potential field along the thickness direction of piezoelectric layers is simulated by a sinusoidal function such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the piezoelectric coupled FG annular Plate with those of an isotropic Core Plate. In a numerical study the emphasis is placed on investigating the effect of varying the gradient index of the FG Plate on the free vibration characteristics of the structure. Also the good agreement between the results of this paper and those of the finite element (FE) analyses validated the presented approach.

Farzad Ebrahimi - One of the best experts on this subject based on the ideXlab platform.

  • An Analytical Model for Free Vibration Analysis of Smart Annular FGM Plates Integrated with Piezoelectric Layers
    international journal of advanced design and manufacturing technology, 2011
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    In this paper, a nonlinear free vibration analysis of thin annular functionally graded (FG) Plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG Plate is presented based on Kirchhoff Plate theory. The material properties of the FGM Core Plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents and the distribution of electric potential field along the thickness direction of piezoelectric layers is simulated by a sinusoidal function such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the piezoelectric coupled FG annular Plate with those of an isotropic Core Plate. In numerical study, the emphasis is placed on investigating the effect of varying the gradient index of FG Plate on free vibration characteristics of the structure. In addition, good agreement between the results of this paper and those of finite element (FE) analyses validated the present approach. The analytical solutions and findings contribute towards a simplified model for the parametric study and understanding of vibration of piezoelectric-coupled FGM annular Plate.

  • FSDPT based study for vibration analysis of piezoelectric coupled annular FGM Plate
    Journal of Mechanical Science and Technology, 2009
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    The vibration behavior of a piezoelectrically actuated thick functionally graded (FG) annular Plate is studied based on first order shear deformation Plate theory (FSDPT). A consistent formulation that satisfies the Maxwell static electricity equation is presented so that the full coupling effect of the piezoelectric layer on the dynamic characteristics of the annular FG Plate can be estimated based on the free vibration results. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the composite Plate with those of an isotropic Core Plate. As a special case, assuming that the material composition of Core Plate varies continuously in the direction of the thickness according to a power law distribution, a comprehensive study is conducted to show the influence of functionally graded index on the vibration behavior of smart structure. Also, the good agreement between the results of this paper and those of the finite element (FE) analyses validates the presented approach.

  • Geometrically nonlinear vibration analysis of piezoelectrically actuated FGM Plate with an initial large deformation
    Journal of Mechanical Science and Technology, 2009
    Co-Authors: Farzad Ebrahimi, Mohammad Hassan Naei, Abbas Rastgoo
    Abstract:

    A theoretical model for geometrically nonlinear vibration analysis of piezoelectrically actuated circular Plates made of functionally grade material (FGM) is presented based on Kirchhoff’s-Love hypothesis with von-Karman type geometrical large nonlinear deformations. To determine the initial stress state and pre-vibration deformations of the smart Plate a nonlinear static problem is solved followed by adding an incremental dynamic state to the pre-vibration state. The derived governing equations of the structure are solved by exact series expansion method combined with perturbation approach. The material properties of the FGM Core Plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents. Control of the FGM Plate’s nonlinear deflections and natural frequencies using high control voltages is studied and their nonlinear effects are evaluated. Numerical results for FG Plates with various mixture of ceramic and metal are presented in dimensionless forms. In a parametric study the emphasis is placed on investigating the effect of varying the applied actuator voltage as well as gradient index of FGM Plate on vibration characteristics of the smart structure.

  • Free vibration analysis of smart annular FGM Plates integrated with piezoelectric layers
    Smart Materials and Structures, 2008
    Co-Authors: Farzad Ebrahimi, Abbas Rastgoo
    Abstract:

    In this paper, a nonlinear free vibration analysis of a thin annular functionally graded (FG) Plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG Plate is presented based on Kirchhoff Plate theory. The material properties of the functionally graded Core Plate are assumed to be graded in the thickness direction according to the power law distribution in terms of the volume fractions of the constituents and the distribution of the electric potential field along the thickness direction of piezoelectric layers is simulated by a sinusoidal function such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for various boundary conditions of the Plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the piezoelectric coupled FG annular Plate with those of an isotropic Core Plate. In a numerical study the emphasis is placed on investigating the effect of varying the gradient index of the FG Plate on the free vibration characteristics of the structure. Also the good agreement between the results of this paper and those of the finite element (FE) analyses validated the presented approach.

Liang Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Geometrical parameters influence on the stiffness of steel sandwich Plates with web-Core
    IOP Conference Series: Materials Science and Engineering, 2017
    Co-Authors: Xiao Xia Jiang, Mohd Ruzaimi Mat Rejab, S. Zhang, Mahadzir Ishak, Liang Zhu
    Abstract:

    Laser welded sandwich Plates with web-Core have found their position in the marine and land vehicles. To implement such design accurately, knowledge about the influence of geometrical parameters on the stiffness is necessary. In this paper, the over-hanging three points bending tests were performed on the laser welded web-Core steel sandwich Plate under quasi-static conditions, together with the finite element (FE) simulations. The following parameters were analysed: the thickness of the face Plate, the spacing of the two Core Plates and the height of the Core Plates. The agreement between experimental measurements and FE results was considered to be good. It is shown that changes of these parameters can contribute to increase or decrease of the stiffness of web-Core sandwich Plate, but the height of the Core Plate has no effect on the shear stiffness as the spacing of the two Core Plates is known. There are linear, exponential and polynomial fitted relationships between the geometrical and the stiffness of the web-Core sandwich Plates.

  • The Strength of Laser Welded Web-Core Steel Sandwich Plates
    Applied Mechanics and Materials, 2014
    Co-Authors: Xiao Xia Jiang, Liang Zhu, Ji Sen Qiao, Jianhong Chen
    Abstract:

    All steel laser welded sandwich Plates have found their position in the marine and land vehicles. To implement such design accurately, knowledge about its strength properties and the influence of laser weld dimensions on strength is necessary. In this paper, the over-hanging three point bending tests were conducted on the laser welded web-Core steel sandwich Plate with various weld dimensions by self-designed device, together with the finite element simulations. The results show that the joint is formed on the first plastic hinge when the load is no longer a linear relationship with the deflection, and the joint cracking when the load reaches the maximum bearing capacity of sandwich Plate. The joint yield load and the maximum bearing capacity of the sandwich Plates increased with the increasing of weld width. Meanwhile, the mode of failure of sandwich Plates also changed: When the weld width is smaller, the mode of failure is joint yield, When the weld width is greater than 3mm, the mode of failure is the combination of partial joint yield, face Plate and Core Plate local yield, while the face Plate and Core Plate yield exists in the whole weld joint. It is necessary to consider the weld width in the design and evaluation of the strength of the laser welded web-Core sandwich Plate.

Xiao Xia Jiang - One of the best experts on this subject based on the ideXlab platform.

  • Geometrical parameters influence on the stiffness of steel sandwich Plates with web-Core
    IOP Conference Series: Materials Science and Engineering, 2017
    Co-Authors: Xiao Xia Jiang, Mohd Ruzaimi Mat Rejab, S. Zhang, Mahadzir Ishak, Liang Zhu
    Abstract:

    Laser welded sandwich Plates with web-Core have found their position in the marine and land vehicles. To implement such design accurately, knowledge about the influence of geometrical parameters on the stiffness is necessary. In this paper, the over-hanging three points bending tests were performed on the laser welded web-Core steel sandwich Plate under quasi-static conditions, together with the finite element (FE) simulations. The following parameters were analysed: the thickness of the face Plate, the spacing of the two Core Plates and the height of the Core Plates. The agreement between experimental measurements and FE results was considered to be good. It is shown that changes of these parameters can contribute to increase or decrease of the stiffness of web-Core sandwich Plate, but the height of the Core Plate has no effect on the shear stiffness as the spacing of the two Core Plates is known. There are linear, exponential and polynomial fitted relationships between the geometrical and the stiffness of the web-Core sandwich Plates.

  • The Strength of Laser Welded Web-Core Steel Sandwich Plates
    Applied Mechanics and Materials, 2014
    Co-Authors: Xiao Xia Jiang, Liang Zhu, Ji Sen Qiao, Jianhong Chen
    Abstract:

    All steel laser welded sandwich Plates have found their position in the marine and land vehicles. To implement such design accurately, knowledge about its strength properties and the influence of laser weld dimensions on strength is necessary. In this paper, the over-hanging three point bending tests were conducted on the laser welded web-Core steel sandwich Plate with various weld dimensions by self-designed device, together with the finite element simulations. The results show that the joint is formed on the first plastic hinge when the load is no longer a linear relationship with the deflection, and the joint cracking when the load reaches the maximum bearing capacity of sandwich Plate. The joint yield load and the maximum bearing capacity of the sandwich Plates increased with the increasing of weld width. Meanwhile, the mode of failure of sandwich Plates also changed: When the weld width is smaller, the mode of failure is joint yield, When the weld width is greater than 3mm, the mode of failure is the combination of partial joint yield, face Plate and Core Plate local yield, while the face Plate and Core Plate yield exists in the whole weld joint. It is necessary to consider the weld width in the design and evaluation of the strength of the laser welded web-Core sandwich Plate.

Meng Shaoping - One of the best experts on this subject based on the ideXlab platform.

  • A novel brace with partial buckling restraint: An experimental and numerical investigation
    Engineering Structures, 2017
    Co-Authors: Chun-lin Wang, Chen Quan, Zeng Bin, Meng Shaoping
    Abstract:

    Abstract For the immediate damage evaluation of a buckling-restrained brace (BRB) after earthquakes, a novel brace with partial buckling restraint was proposed. In the novel brace called the partially buckling-restrained brace (PBRB), only the edge parts of the Core member are restrained, and the middle portion of the Core member, the unrestrained part, is designed for visual inspection. This paper focuses on the partial restraining mechanism of the PBRB, and three PBRB specimens were tested and compared with two conventional BRB specimens. The unrestrained ratio of the width of the unrestrained part to the thickness of the same part was studied as one of the key parameters that affects the behaviour of the PBRB. Even if the PBRB shows relatively lower fatigue properties and higher compression strength adjustment factors compared with the conventional BRB, the behaviour of the PBRB is still acceptable. The PBRB with a large unrestrained ratio fails at the end of the yielding Core Plate, where the unrestrained buckling deformation of the Core Plate is significant, but the fracture of the PBRB with a small unrestrained ratio occurs around the stopper, similar to the failure mode of the BRB. Numerical results show that the maximum plastic strain concentrates in the wave valley of the ends of the yielding Core Plate for the PBRB with the large unrestrained ratio. To make sure that the behaviour of the PBRB is comparable to that of the conventional BRB, it is recommended that the unrestrained ratio should be less than 5.

  • Effect of the unbonding materials on the mechanic behavior of all-steel buckling-restrained braces
    Engineering Structures, 2016
    Co-Authors: Chen Quan, Meng Shaoping, Chun-lin Wang, Zeng Bin
    Abstract:

    Abstract Seven all-steel buckling-restrained braces (BRBs) were tested under cyclic loading to investigate the effect of the unbonding materials on the performance of BRBs, via the employment of a layer of 1-mm thick butyl rubber or pure air gap between the Core Plate and the restraining system. Test results indicate that all the BRBs exhibited rather well energy dissipation capacities and sustained cumulative plastic deformations over 1000 times the yield strain. However, significantly higher compression strength adjustment factor β was developed for the specimens without the unbonding materials, due to the gradually increasing friction force and the jamming between the end of the Core Plate and the restraining members. Moreover, the gradually increasing friction force and the jamming also induced the considerably nonuniform residual deformation for the specimens without the unbonding materials both observed in the test and the finite element models. Especially, for high performance BRBs with relatively long yielding segment and thin Core Plate, the unbonding materials are recommended to apply.

  • Experimental research on effect of unbonding material on mechanical behavior of all-steel buckling-restrained brace
    Journal of Building Structures, 2013
    Co-Authors: Meng Shaoping
    Abstract:

    Two all-steel BRB specimens with identical dimensions were designed in the experiment and only one specimen employed the unbonding material between the Core Plate and the restraining members.Static cyclic loading tests of the two specimens were performed in order to evaluate the effect of the unbonding material on the all-steel BRB' s performance,including the failure mode,hysteretic behavior,compression strength adjustment factor and residual deformation.It is concluded from test results that two BRB specimens have good low-cycle fatigue performance.Moreover,the number of cycle of the BRB with the unbonding material under the constant loading amplitude increases by 21%,which shows that its low-cycle fatigue performance is better than the BRB without the unbonding material.The compression strength adjustment factor of the BRB without the unbonding material is much greater than one with the unbonding material.The unbonding material can decrease the frictional force between the Core Plate and the restraining members and can prevent the Core Plate from wear.The frictional shear force causes the middle region of the yield segment to shrink and the end region to expand.This observation is very clear for the BRB without the unbonding material and its expanded Core Plate squeezes the fillers.