K. Malekzadeh - Academia.edu (original) (raw)

Papers by K. Malekzadeh

Research paper thumbnail of Free Vibration of Sandwich Panels with Smart Magneto-Rheological Layers and Flexible Cores

Journal of Solid Mechanics, 2016

This is the first study on the free vibrational behavior of sandwich panels with flexible core in... more This is the first study on the free vibrational behavior of sandwich panels with flexible core in the presence of smart sheets of oil which is capable of the excitation of magnetic field. In order to model the core, the improved high order theory of sandwich sheets was used by a polynomial with unknown coefficients first degree shear theory was used for the sheets. The derived equations based on Hamilton principle with simple support boundary condition for upper and lower sheets were solved using Navier technique. Accuracy and precision of the theory were investigated by comparing the results of this study with those of analytical and numerical works. In the conclusion section, effect of the intensity of magnetic field and other physical parameters including ratio of sheet's length to width, ratio of sheet's length to thickness, ratio of core thickness to sheet's overall thickness, and ratio of oil layer thickness to sheet's overall thickness on natural frequency was...

Research paper thumbnail of Prediction of low-velocity impact response of composite sandwich panels using new three degrees-of-freedom model

Research paper thumbnail of Paper: ISOLATION AND IDENTIFICATION OF L-ASPARAGINASE PRODUCING ACTINOMYCETES FROM PERSIAN GULF

Research paper thumbnail of Isolation and identification of L-asparaginase producing actinomycetes from Persian Gulf

Research paper thumbnail of Higher-order dynamic response of composite sandwich panels with flexible core under simultaneous low-velocity impacts of multiple small masses

Research paper thumbnail of Temperature-dependent buckling analysis of sandwich truncated conical shells with FG facesheets

Composite Structures, 2015

ABSTRACT In this study, an improved high-order theory is presented for temperature-dependent buck... more ABSTRACT In this study, an improved high-order theory is presented for temperature-dependent buckling analysis of sandwich conical shell with thin functionally graded (FG) facesheets and homogenous soft core. First shear deformation theory (FSDT) is used for the facesheets and cubic functions are assumed for the transverse and in-plane displacements of the core. The nonlinear Von-Karman type relations are used to obtain the strain components. The equilibrium equations are derived via principle of minimum potential energy. Analytical solution for static analysis of simply supported sandwich conical shells under axial in-plane compressive load and in the temperature environments is performed using Galerkin’s solution. Numerical modeling is made by ABAQUS finite element (FE) code. The comparison shows that the present results are in good agreement with the results in the literature and the present FE results.

Research paper thumbnail of Association of genetic polymorphism of the DNA base excision repair gene (APE-1 Asp/148 Glu) and HPV type (16/18) with the risk of cervix cancer in north Indian population

Cancer biomarkers : section A of Disease markers, 2008

Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined wo... more Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined world wide incidence of almost half a million new cases. Reduced DNA repair capacity (DRC) can render a high risk of developing many types of cancer; including cervical cancer. Polymorphisms in DNA repair genes may contribute the genetic instability and carcinogenesis. Smoking experience and use of oral contraceptives have been confirmed to be risk factors for cervical cancer. The purpose of the present study was, therefore to investigate APE-1 genotypes (Asp/Asp, Asp/Glu, Glu/Glu) with different histological subtypes in cases compared with controls. It has been observed that Asp/Glu with Glu/Glu genotypes that combined we observed statistically significant with protective effect for developing of cervix cancer (OR-0.51, 95% CI 0.31-0.83, p-0.006). The combined Asp/Glu with Glu/Glu genotypes who were using oral contraceptives were shown to be statistically significant with reduced risk of ...

Research paper thumbnail of Free Vibrations of Thick Rectangular Composite Plate with Uniformly Distributed Attached Mass Including Stiffness Effect

ABSTRACT In this article, free vibrations of rectangular composite plate with and without a unifo... more ABSTRACT In this article, free vibrations of rectangular composite plate with and without a uniformly distributed attached mass are analyzed using the standard Galerkin procedure. The results of free vibrations without distributed attached mass are validated by some common literatures. The stiffness effect of the distributed attached mass is taken into account and the results are compared with those well-known published results in which this effect is not considered. Various results for isotropic and composite rectangular plates under a variety of conditions such as variation in thickness of the plate, variation in thickness of the distributed attached mass, fiber orientations and layup, and various elastic moduli for the distributed attached mass are presented in this article. In simple cases, to verify the results, other theories such as first-order shear deformation theory and classical lamination plate theory are used. Adding the stiffness of the attached mass increases the natural frequencies of the system.

Research paper thumbnail of Dynamic response of pre-stressed fibre metal laminate (FML) circular cylindrical shells subjected to lateral pressure pulse loads

Research paper thumbnail of ﻞﻧﺎﭘ ﻲﮑﻴﻣﺎﻨﻳﺩ ﺦﺳﺎﭘ ﺮﺑ ﻱﺍ ﻪﺒﺗﺮﻣ ﺪﻨﻤﻓﺪﻫ ﻪﺘﺴﻫ ﺮﺛﺍ ﻲﺿﺮﻋ ﻪﺑﺮﺿ ﺖﺤﺗ ﻲﭽﻳﻭﺪﻧﺎﺳ ﺎﺑ ﻦﻴﻳﺎﭘ ﺖﻋﺮﺳ‎

Research paper thumbnail of High Order Analytical and 3D Finite Element Solution for Biaxial Wrinkling Analysis of Composite-Faced Sandwich Plates with Soft Core

Research paper thumbnail of 预应力纤维金属层板圆柱壳受侧向脉冲压力时的动力响应

Research paper thumbnail of Effect of distributed attached patches on fundamental natural frequency of thick cylindrical and spherical shells using higher-order shell theory

Research paper thumbnail of Dynamic Response of Composite Sandwich Beams with Arbitrary FG Cores Subjected to Low Velocity Impact

ABSTRACT Using an improved higher order sandwich panel theory (IHSAPT), the dynamic response of a... more ABSTRACT Using an improved higher order sandwich panel theory (IHSAPT), the dynamic response of a sandwich beam with arbitrary cores (foam or functionally graded materials) subjected to single impact at arbitrary impacted face sheet and arbitrary locations is studied. The formulation uses the first order shear deformation theory for the composite face sheets and a polynomial description of the displacements fields in the core which is based on the displacement field of the second Frostig's model. The unknowns are the coefficients of these polynomials in addition to the displacements of the various face sheets. It is assumed that the impactor impacted normally and simultaneously over the top or bottom face-sheets. The impact force between the impacted face sheet and the impactor is treated as the internal force of the system and in this study for the first time in order to simulate the impact phenomena, two models are presented: first, the linearized spring-mass model with two degrees of freedom (simply called TDOF) which can be solved by a new analytical method, second, the modified Hertz's model which uses the perfect form of contact law (perfect model). An impact problem of sandwich beam is first solved and the results obtained from TDOF and perfect models are validated by comparing with the analytical and numerical results published in the literature and also together. The agreement between the results is quite good. Then, the effect of various types of FGM function and its power and core to beam thickness ratio on the dynamic behavior of sandwich beam are studied.

Research paper thumbnail of Paper: FREE VIBRATION ANALYSIS OF SANDWICH BEAMS USING IMPROVED DYNAMIC STIFFNESS METHOD

Research paper thumbnail of 运用表面响应法的低速撞击下智能组合板分析和优化

Research paper thumbnail of The Impact of IL-18 and IFN-γ on Severity of Malaria and Quality of Treatment

Research paper thumbnail of Low-velocity impact response of active thin-walled hybrid composite structures embedded with SMA wires

Thin-Walled Structures, 2007

Effect of some important parameters on low-velocity impact response of the active thin-walled hyb... more Effect of some important parameters on low-velocity impact response of the active thin-walled hybrid composite plates embedded with the shape memory alloy (SMA) wires is investigated in this paper. The interaction between the impactor and the composite plate is considered in the impact analysis. The SMA wires are embedded within the layers of the composite laminate. The effect of the

Research paper thumbnail of Analysis and optimization of smart hybrid composite plates subjected to low-velocity impact using the response surface methodology (RSM)

Thin-Walled Structures, 2008

Optimization of the volume fraction, the orientation and the through thickness location of the sh... more Optimization of the volume fraction, the orientation and the through thickness location of the shape memory alloy (SMA) wires was used in order to minimize the maximum transverse deflection of the hybrid composite plate during the low-velocity impact phenomena. The prediction of optimal conditions of good geometrical properties of SMA wires in smart hybrid composites plays an important role in

Research paper thumbnail of Dynamic response of fiber–metal laminates (FMLs) subjected to low-velocity impact

Thin-Walled Structures, 2010

ABSTRACT Fiber–metal laminates (FMLs) are high-performance hybrid structures based on alternating... more ABSTRACT Fiber–metal laminates (FMLs) are high-performance hybrid structures based on alternating stacked arrangements of fiber-reinforced plastic (FRP) plies and metal alloy layers. The response of FMLs subjected to low-velocity impact is studied in this paper. The aluminum (Al) sheets are placed instead of some of layers of FRP plies. The effect of the Al layers on contact force history, deflection, in-plane strains and stresses of the structure is studied. The first-order shear deformation theory as well as the Fourier series method is used to solve the governing equations of the composite plate analytically. The interaction between the impactor and the plate is modeled with the use of a two degrees-of-freedom system, consisting of springs-masses. The Choi's linearized Hertzian contact model is used in the impact analysis of the hybrid composite plate. The results indicated that some of the parameters like the layer sequence, mass and velocity of the impactor in a constant impact energy level, and the aspect ratio (a/b) of the plate are important factors affecting the dynamic response of the FMLs. Interaction among the mentioned geometrical parameters and material parameters like the aluminum 2024-T3 alloy layers is studied. The numerical results that are presented in this paper hitherto not reported in the published literature.

Research paper thumbnail of Free Vibration of Sandwich Panels with Smart Magneto-Rheological Layers and Flexible Cores

Journal of Solid Mechanics, 2016

This is the first study on the free vibrational behavior of sandwich panels with flexible core in... more This is the first study on the free vibrational behavior of sandwich panels with flexible core in the presence of smart sheets of oil which is capable of the excitation of magnetic field. In order to model the core, the improved high order theory of sandwich sheets was used by a polynomial with unknown coefficients first degree shear theory was used for the sheets. The derived equations based on Hamilton principle with simple support boundary condition for upper and lower sheets were solved using Navier technique. Accuracy and precision of the theory were investigated by comparing the results of this study with those of analytical and numerical works. In the conclusion section, effect of the intensity of magnetic field and other physical parameters including ratio of sheet's length to width, ratio of sheet's length to thickness, ratio of core thickness to sheet's overall thickness, and ratio of oil layer thickness to sheet's overall thickness on natural frequency was...

Research paper thumbnail of Prediction of low-velocity impact response of composite sandwich panels using new three degrees-of-freedom model

Research paper thumbnail of Paper: ISOLATION AND IDENTIFICATION OF L-ASPARAGINASE PRODUCING ACTINOMYCETES FROM PERSIAN GULF

Research paper thumbnail of Isolation and identification of L-asparaginase producing actinomycetes from Persian Gulf

Research paper thumbnail of Higher-order dynamic response of composite sandwich panels with flexible core under simultaneous low-velocity impacts of multiple small masses

Research paper thumbnail of Temperature-dependent buckling analysis of sandwich truncated conical shells with FG facesheets

Composite Structures, 2015

ABSTRACT In this study, an improved high-order theory is presented for temperature-dependent buck... more ABSTRACT In this study, an improved high-order theory is presented for temperature-dependent buckling analysis of sandwich conical shell with thin functionally graded (FG) facesheets and homogenous soft core. First shear deformation theory (FSDT) is used for the facesheets and cubic functions are assumed for the transverse and in-plane displacements of the core. The nonlinear Von-Karman type relations are used to obtain the strain components. The equilibrium equations are derived via principle of minimum potential energy. Analytical solution for static analysis of simply supported sandwich conical shells under axial in-plane compressive load and in the temperature environments is performed using Galerkin’s solution. Numerical modeling is made by ABAQUS finite element (FE) code. The comparison shows that the present results are in good agreement with the results in the literature and the present FE results.

Research paper thumbnail of Association of genetic polymorphism of the DNA base excision repair gene (APE-1 Asp/148 Glu) and HPV type (16/18) with the risk of cervix cancer in north Indian population

Cancer biomarkers : section A of Disease markers, 2008

Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined wo... more Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined world wide incidence of almost half a million new cases. Reduced DNA repair capacity (DRC) can render a high risk of developing many types of cancer; including cervical cancer. Polymorphisms in DNA repair genes may contribute the genetic instability and carcinogenesis. Smoking experience and use of oral contraceptives have been confirmed to be risk factors for cervical cancer. The purpose of the present study was, therefore to investigate APE-1 genotypes (Asp/Asp, Asp/Glu, Glu/Glu) with different histological subtypes in cases compared with controls. It has been observed that Asp/Glu with Glu/Glu genotypes that combined we observed statistically significant with protective effect for developing of cervix cancer (OR-0.51, 95% CI 0.31-0.83, p-0.006). The combined Asp/Glu with Glu/Glu genotypes who were using oral contraceptives were shown to be statistically significant with reduced risk of ...

Research paper thumbnail of Free Vibrations of Thick Rectangular Composite Plate with Uniformly Distributed Attached Mass Including Stiffness Effect

ABSTRACT In this article, free vibrations of rectangular composite plate with and without a unifo... more ABSTRACT In this article, free vibrations of rectangular composite plate with and without a uniformly distributed attached mass are analyzed using the standard Galerkin procedure. The results of free vibrations without distributed attached mass are validated by some common literatures. The stiffness effect of the distributed attached mass is taken into account and the results are compared with those well-known published results in which this effect is not considered. Various results for isotropic and composite rectangular plates under a variety of conditions such as variation in thickness of the plate, variation in thickness of the distributed attached mass, fiber orientations and layup, and various elastic moduli for the distributed attached mass are presented in this article. In simple cases, to verify the results, other theories such as first-order shear deformation theory and classical lamination plate theory are used. Adding the stiffness of the attached mass increases the natural frequencies of the system.

Research paper thumbnail of Dynamic response of pre-stressed fibre metal laminate (FML) circular cylindrical shells subjected to lateral pressure pulse loads

Research paper thumbnail of ﻞﻧﺎﭘ ﻲﮑﻴﻣﺎﻨﻳﺩ ﺦﺳﺎﭘ ﺮﺑ ﻱﺍ ﻪﺒﺗﺮﻣ ﺪﻨﻤﻓﺪﻫ ﻪﺘﺴﻫ ﺮﺛﺍ ﻲﺿﺮﻋ ﻪﺑﺮﺿ ﺖﺤﺗ ﻲﭽﻳﻭﺪﻧﺎﺳ ﺎﺑ ﻦﻴﻳﺎﭘ ﺖﻋﺮﺳ‎

Research paper thumbnail of High Order Analytical and 3D Finite Element Solution for Biaxial Wrinkling Analysis of Composite-Faced Sandwich Plates with Soft Core

Research paper thumbnail of 预应力纤维金属层板圆柱壳受侧向脉冲压力时的动力响应

Research paper thumbnail of Effect of distributed attached patches on fundamental natural frequency of thick cylindrical and spherical shells using higher-order shell theory

Research paper thumbnail of Dynamic Response of Composite Sandwich Beams with Arbitrary FG Cores Subjected to Low Velocity Impact

ABSTRACT Using an improved higher order sandwich panel theory (IHSAPT), the dynamic response of a... more ABSTRACT Using an improved higher order sandwich panel theory (IHSAPT), the dynamic response of a sandwich beam with arbitrary cores (foam or functionally graded materials) subjected to single impact at arbitrary impacted face sheet and arbitrary locations is studied. The formulation uses the first order shear deformation theory for the composite face sheets and a polynomial description of the displacements fields in the core which is based on the displacement field of the second Frostig's model. The unknowns are the coefficients of these polynomials in addition to the displacements of the various face sheets. It is assumed that the impactor impacted normally and simultaneously over the top or bottom face-sheets. The impact force between the impacted face sheet and the impactor is treated as the internal force of the system and in this study for the first time in order to simulate the impact phenomena, two models are presented: first, the linearized spring-mass model with two degrees of freedom (simply called TDOF) which can be solved by a new analytical method, second, the modified Hertz's model which uses the perfect form of contact law (perfect model). An impact problem of sandwich beam is first solved and the results obtained from TDOF and perfect models are validated by comparing with the analytical and numerical results published in the literature and also together. The agreement between the results is quite good. Then, the effect of various types of FGM function and its power and core to beam thickness ratio on the dynamic behavior of sandwich beam are studied.

Research paper thumbnail of Paper: FREE VIBRATION ANALYSIS OF SANDWICH BEAMS USING IMPROVED DYNAMIC STIFFNESS METHOD

Research paper thumbnail of 运用表面响应法的低速撞击下智能组合板分析和优化

Research paper thumbnail of The Impact of IL-18 and IFN-γ on Severity of Malaria and Quality of Treatment

Research paper thumbnail of Low-velocity impact response of active thin-walled hybrid composite structures embedded with SMA wires

Thin-Walled Structures, 2007

Effect of some important parameters on low-velocity impact response of the active thin-walled hyb... more Effect of some important parameters on low-velocity impact response of the active thin-walled hybrid composite plates embedded with the shape memory alloy (SMA) wires is investigated in this paper. The interaction between the impactor and the composite plate is considered in the impact analysis. The SMA wires are embedded within the layers of the composite laminate. The effect of the

Research paper thumbnail of Analysis and optimization of smart hybrid composite plates subjected to low-velocity impact using the response surface methodology (RSM)

Thin-Walled Structures, 2008

Optimization of the volume fraction, the orientation and the through thickness location of the sh... more Optimization of the volume fraction, the orientation and the through thickness location of the shape memory alloy (SMA) wires was used in order to minimize the maximum transverse deflection of the hybrid composite plate during the low-velocity impact phenomena. The prediction of optimal conditions of good geometrical properties of SMA wires in smart hybrid composites plays an important role in

Research paper thumbnail of Dynamic response of fiber–metal laminates (FMLs) subjected to low-velocity impact

Thin-Walled Structures, 2010

ABSTRACT Fiber–metal laminates (FMLs) are high-performance hybrid structures based on alternating... more ABSTRACT Fiber–metal laminates (FMLs) are high-performance hybrid structures based on alternating stacked arrangements of fiber-reinforced plastic (FRP) plies and metal alloy layers. The response of FMLs subjected to low-velocity impact is studied in this paper. The aluminum (Al) sheets are placed instead of some of layers of FRP plies. The effect of the Al layers on contact force history, deflection, in-plane strains and stresses of the structure is studied. The first-order shear deformation theory as well as the Fourier series method is used to solve the governing equations of the composite plate analytically. The interaction between the impactor and the plate is modeled with the use of a two degrees-of-freedom system, consisting of springs-masses. The Choi's linearized Hertzian contact model is used in the impact analysis of the hybrid composite plate. The results indicated that some of the parameters like the layer sequence, mass and velocity of the impactor in a constant impact energy level, and the aspect ratio (a/b) of the plate are important factors affecting the dynamic response of the FMLs. Interaction among the mentioned geometrical parameters and material parameters like the aluminum 2024-T3 alloy layers is studied. The numerical results that are presented in this paper hitherto not reported in the published literature.