- Massachusetts Institute of Technology (MIT), Mechanical Engineering, Department MemberTurkish Air Force Academy, Aerospace Engineering, Emeritusadd
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A preliminary computational study has been conducted which investigates the dynamic response of sandwich panels with cores constructed of varying cellular topologies subjected to air blast loading. Six different cells were selected for... more
A preliminary computational study has been conducted which investigates the dynamic response of sandwich panels with cores constructed of varying cellular topologies subjected to air blast loading. Six different cells were selected for comparison. Of these, the hexagonal cell represents a conventional core topology, whereas the other five are “auxetic” geometries with negative Poisson’s ratios. Following the application of a blast load, the double-arrowhead core geometry produced the lowest peak deflection.
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Research Interests: Engineering and Crash
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Impact behavior of sandwich panels with auxetic and hexagonal honeycomb cores are investigated experimentally and numerically. Re-entrant and anti-tetrachiral geometries are considered for auxetic cores. In the experimental side of the... more
Impact behavior of sandwich panels with auxetic and hexagonal honeycomb cores are investigated experimentally and numerically. Re-entrant and anti-tetrachiral geometries are considered for auxetic cores. In the experimental side of the study, auxetic and honeycomb cores are produced using a 3D printer. The sandwich panels are then produced by attaching aluminium face sheets and cores. The impact tests are performed using a particle impact test system. The numerical analyses are achieved by using LSDYNA finite element software. The deformation results are compared and the effect of having different type of core is evaluated.
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The use of the advanced laminated composites is become more important in the structures of many engineering applications such as space stations, aerospace vehicles, automotives and marine structures. Also, with the increasing use of... more
The use of the advanced laminated composites is become more important in the structures of many engineering applications such as space stations, aerospace vehicles, automotives and marine structures. Also, with the increasing use of recent composite material structures in the military applications, nonlinear dynamic analysis of these materials subjected to blast loads resulting from fuel and nuclear explosions, and the rush of sonic boom are becoming increasingly more significant. The nonlinear dynamic response of a blast loaded laminated basalt composite plate has been investigated experimentally and numerically. The laminated basalt composite plate is fully-clamped at all edges. For numerical analyses, the equations of motion for the plate are derived by the use of the virtual work principle. Approximate solutions are assumed for the space domain and substituted into the equations of motion. Then the Galerkin Method is used to obtain the nonlinear differential equations in the tim...
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Résumé/Abstract This research deals with the derivation and solution of nonlinear dynamic equations of a clamped laminated plate exposed to blast load including structural damping effects. Dynamic equations of the plate are derived by the... more
Résumé/Abstract This research deals with the derivation and solution of nonlinear dynamic equations of a clamped laminated plate exposed to blast load including structural damping effects. Dynamic equations of the plate are derived by the use of the virtual work principle. ...
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Bu çalışmada mühendislik uygulamalarında pek çok kullanım alanı olan katmanlı kompozit plakla-rın nonlineer dinamik davranışları parametrik olarak incelenmiştir. Çalışma esnasında dikdörtgen plak yapılar seçilmiştir. Plaklar konsol plak... more
Bu çalışmada mühendislik uygulamalarında pek çok kullanım alanı olan katmanlı kompozit plakla-rın nonlineer dinamik davranışları parametrik olarak incelenmiştir. Çalışma esnasında dikdörtgen plak yapılar seçilmiştir. Plaklar konsol plak olarak mesnetlenmiş ve anlık ...
şan patlamalar etkisiyle gerekse ses hizinin a şilmasinda olu şan güçlü şok dalgalari nedeniyle anlik basinç yüklerine ve dolayisiyla zamana ba ğli diş uyarimlara maruz kalabilmektedirler. Uçaklar, denizaltilar ve basinç tanklarina kadar... more
şan patlamalar etkisiyle gerekse ses hizinin a şilmasinda olu şan güçlü şok dalgalari nedeniyle anlik basinç yüklerine ve dolayisiyla zamana ba ğli diş uyarimlara maruz kalabilmektedirler. Uçaklar, denizaltilar ve basinç tanklarina kadar bir çok uygulamada önem arz eden bu tür yüklere hava-uzay araçlarina ait yapilarin dinamik cevabinin belirlenmesine yönelik metodlarin bulunmasi, bu yüklerin hava-uzay araçlarinin yapisal bütünlü ğü ve işletim
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This review is conducted with emphasis on the analysis performed for laminated composite plates that are subjected to blast loads. A general discussion and classification of the different laminated plate theories is also given. Various... more
This review is conducted with emphasis on the analysis performed for laminated composite plates that are subjected to blast loads. A general discussion and classification of the different laminated plate theories is also given. Various types of time-dependent external blast pulse models that are widely used in the literature are summarized. Main aim is to categorize previous laminated plate theories in a general sense and give an overview on the development, characteristics and applications of numerical methods on the response of laminated composite plates subjected to blast loads. This review article contains 142 references.
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ABSTRACT The engineering structures may be subjected to the dynamic loads such as blast. Therefore, in the design of such structures, the effect of the blast loading should be taken into account. Several studies are reported on both free... more
ABSTRACT The engineering structures may be subjected to the dynamic loads such as blast. Therefore, in the design of such structures, the effect of the blast loading should be taken into account. Several studies are reported on both free vibration and dynamic response analysis of isotropic, orthotropic and laminated composite plates subjected to air blast loading. In all these studies, only the effect of the blast is taken into account. However, because of the initial situation, in-plane forces may exist and may affect the dynamic response of the plate subjected to the blast loading. In this study, a closed form solution is presented for the simply supported laminated composite plates subjected to a combined loading case which includes both the blast and the in-plane forces. In-plane stiffness and inertia effects are considered in the formulation of the problem and transverse shear stresses are ignored. The geometric nonlinearity effects are taken into account by using the von Kármán large deflection theory of thin plates. Approximate solution functions are assumed for the space domain and substituted into the equations of motion. The Galerkin method is used to obtain the nonlinear differential equations in the time domain. The finite difference method is applied to solve the system of coupled nonlinear equations. The displacement-time and strain-time histories are obtained for different combined loading configurations.
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ABSTRACT Purpose ‐ The purpose of this paper is to produce and investigate a reliable and effective aircraft brake lining material. Design/methodology/approach ‐ In total, four different Cu-based brake lining samples were produced by... more
ABSTRACT Purpose ‐ The purpose of this paper is to produce and investigate a reliable and effective aircraft brake lining material. Design/methodology/approach ‐ In total, four different Cu-based brake lining samples were produced by powder metallurgy. The produced samples were tested in an experimental setup on friction, wear and mechanical performance, then metallographic and scanning electron microscope inspections were performed. Hardness, compression strength and density of copper-based brake linings were also tested. Moreover, a numerical simulation of the structural reaction of a sample under compression was carried out by using ANSYS. Findings ‐ According to tests, suitable aircraft brake lining material composition would be 75% Cu, 5% Fe, 5% Sn, 5% Graphite, 5% SiO2, 5% MoS2. Practical implications ‐ The paper will help designers choose the most proper ingredient combination for aircraft brake lining materials. Originality/value ‐ The paper notes that adding silicon dioxide and graphite forms a porosive structure. In addition, porosity brings a low strength and high wear rate.
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ABSTRACT This paper deals with the detailed analysis and discussion of nonlinear static analysis of a laminated composite plate subjected to uniform pressure load. Governing equations of the plate are derived by the use of the virtual... more
ABSTRACT This paper deals with the detailed analysis and discussion of nonlinear static analysis of a laminated composite plate subjected to uniform pressure load. Governing equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a simply supported plate are assumed for the plate domain. The single term approximation functions are selected by considering the nonlinear static deformations of plate. The solution is obtained using the Newmark method in MATLAB software. The plate is also modeled and analyzed using ANSYS software using SHELL91 elements. The variation of membrane, linear and nonlinear bending terms are obtained along a characteristic line on the plate and the numerical and finite element results are compared. The results are discussed in detail considering the nonlinear static behavior of the laminated composite plate and the main reasons of discrepancies are discussed. Dynamic behavior of the plate is explained considering the nonlinear static behavior.
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Nonlinear Response of a Sandwich Plate Subjected to Blast Load. [ASME Conference Proceedings 2007, 169 (2007)]. Ali Baş, Zafer Kazancı, Zahit Mecitoğlu. Abstract. Present work includes in-plane stiffness and inertia effects on the motion... more
Nonlinear Response of a Sandwich Plate Subjected to Blast Load. [ASME Conference Proceedings 2007, 169 (2007)]. Ali Baş, Zafer Kazancı, Zahit Mecitoğlu. Abstract. Present work includes in-plane stiffness and inertia effects on the motion of a sandwich plate under blast load. ...
ABSTRACT The axial crushing and crashing of thin-walled high-strength steel tubes is performed using 3D-shell finite elements and an implicit time integration scheme. The calculated results are compared with published experimental data... more
ABSTRACT The axial crushing and crashing of thin-walled high-strength steel tubes is performed using 3D-shell finite elements and an implicit time integration scheme. The calculated results are compared with published experimental data and results obtained using explicit time integration. The objective is to show that, while for such analyses generally explicit time integration is used, with the current state of the art also an implicit time integration solution should be considered, and such solution approach can provide an effective alternative for a simulation.
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ABSTRACT Nonlinear dynamic responses of a laminated hybrid composite plate subjected to time-dependent pulses are investigated. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric... more
ABSTRACT Nonlinear dynamic responses of a laminated hybrid composite plate subjected to time-dependent pulses are investigated. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a clamped plate are assumed for the space domain. The single term approximation functions are selected by considering the nonlinear static deformation of plate obtained using the finite element method. The Galerkin Method is used to obtain the nonlinear differential equations in the time domain and a MATLAB software code is written to solve nonlinear coupled equations by using the Newmark Method. The results of approximate-numerical analysis are obtained and compared with the finite element results. Transient loading conditions considered include blast, sine, rectangular, and triangular pulses. A parametric study is conducted considering the effects of peak pressure, aspect ratio, fiber orientation and thicknesses.
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The dynamic behaviors of laminated flat and tapered composite plates subjected to blast loads are investigated. Numerical solution techniques and their computational applications which are proposed before in the literature are summarized... more
The dynamic behaviors of laminated flat and tapered composite plates subjected to blast loads are investigated. Numerical solution techniques and their computational applications which are proposed before in the literature are summarized to show the accuracy and prediction of the response of blast loaded laminated composite plates with and without damping effects. It was shown the effect of damping is not significantly effective for the first peak response. However, it is considerable with the second peak and it becomes greater as time increases. The effect of chosen displacement functions for the approximate-numerical methods is indicated. Deflection and strain–time histories of plates obtained from experiment, finite element, and approximate-numerical methods are compared and found a good agreement.
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This review is conducted with emphasis on the analysis performed for laminated composite plates that are subjected to blast loads. A general discussion and classification of the different laminated plate theories is also given. Various... more
This review is conducted with emphasis on the analysis performed for laminated composite plates that are subjected to blast loads. A general discussion and classification of the different laminated plate theories is also given. Various types of time-dependent external blast pulse models that are widely used in the literature are summarized. Main aim is to categorize previous laminated plate theories in a general sense and give an overview on the development, characteristics and applications of numerical methods on the response of laminated composite plates subjected to blast loads. This review article contains 142 references.
Research Interests:
This paper deals with the detailed analysis and discussion of nonlinear static analysis of a laminated composite plate subjected to uniform pressure load. Governing equations of the plate are derived by the use of the virtual work... more
This paper deals with the detailed analysis and discussion of nonlinear static analysis of a laminated composite plate subjected to uniform pressure load. Governing equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a simply supported plate are assumed for the plate domain. The single term approximation functions are selected by considering the nonlinear static deformations of plate. The solution is obtained using the Newmark method in MATLAB software. The plate is also modeled and analyzed using ANSYS software using SHELL91 elements. The variation of membrane, linear and nonlinear bending terms are obtained along a characteristic line on the plate and the numerical and finite element results are compared. The results are discussed in detail considering the nonlinear static behavior of the laminated composite plate and the main reasons of discrepancies are discussed. Dynamic behavior of the plate is explained considering the nonlinear static behavior.
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The nonlinear dynamic response of laminated basalt composite plates has been investigated under dynamic loads. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. All edges... more
The nonlinear dynamic response of laminated basalt composite plates has been investigated under dynamic loads. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. All edges simply supported boundary conditions are considered. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solutions are assumed for the space domain and substituted into the equations of motion. Then the Galerkin Method is used to obtain the nonlinear differential equations in the time domain. The finite difference and Newmark methods are applied to solve the system of coupled nonlinear equations. The effects of different loading conditions on the laminated basalt composites have been investigated. A parametric study is conducted considering the effects of aspect ratio, fiber orientation, peak pressure values, thickness, and waveform parameter. The objective is to show that, the laminated basalt composites would be a good alternative for structures under dynamic loads.
The axial crushing and crashing of thin-walled high-strength steel tubes is performed using 3D-shell finite elements and an implicit time integration scheme. The calculated results are compared with published experimental data and results... more
The axial crushing and crashing of thin-walled high-strength steel tubes is performed using 3D-shell finite elements and an implicit time integration scheme. The calculated results are compared with published experimental data and results obtained using explicit time integration. The objective is to show that, while for such analyses generally explicit time integration is used, with the current state of the art also an implicit time integration solution should be considered, and such solution approach can provide an effective alternative for a simulation.
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In this study, the effect of in-plane deformations on the dynamic behavior of laminated plates is investigated. For this purpose, the displacement-time and strain-time histories obtained from the large deflection analysis of laminated... more
In this study, the effect of in-plane deformations on the dynamic behavior of laminated plates is investigated. For this purpose, the displacement-time and strain-time histories obtained from the large deflection analysis of laminated plates are compared for the cases with and without including in-plane deformations. For the first one, in-plane stiffness and inertia effects are considered when formulating the dynamic response of the laminated composite plate subjected to the blast loading. Then, the problem is solved without considering the in-plane deformations. The geometric nonlinearity effects are taken into account by using the von Kármán large deflection theory of thin plates and transverse shear stresses are ignored for both cases. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solution functions are assumed for the space domain and substituted into the equations of motion. Then, the Galerkin method is used to obtain the nonlinear algebraic differential equations in the time domain. The effects of the magnitude of the blast load, the thickness of the plate and boundary conditions on the in-plane deformations are investigated.
"Purpose - The objective of this paper is to produce and investigate a reliable and effective aircraft brake lining material. Design/methodology/approach - Four different Cu based brake lining samples were produced by the way of powder... more
"Purpose - The objective of this paper is to produce and investigate a reliable and effective aircraft brake lining material.
Design/methodology/approach - Four different Cu based brake lining samples were produced by the way of powder metallurgy. Produced samples were tested in an experimental setup on friction, wear and mechanical performance. Then metallografic and scanning electron microscope inspections were performed. Hardness, compression strength and density of copper based brake linings were also tested. Moreover, a numerical simulation of the structural reaction of a sample under compression was carried out by using ANSYS.
Findings - According to tests, it is found that suitable brake lining material composition would be 75% Cu, 5% Fe, 5% Sn, 5% Graphite, 5% SiO2, 5% MoS2.
Practical implications - This paper attempts to help designers choose the most proper ingredient combination for aircraft brake lining materials.
Originality/value - It has been observed that adding Silisium dioxide and Graphite forms a porositive structure. In addition, porosity brings a low strength and also high wear rate."
Design/methodology/approach - Four different Cu based brake lining samples were produced by the way of powder metallurgy. Produced samples were tested in an experimental setup on friction, wear and mechanical performance. Then metallografic and scanning electron microscope inspections were performed. Hardness, compression strength and density of copper based brake linings were also tested. Moreover, a numerical simulation of the structural reaction of a sample under compression was carried out by using ANSYS.
Findings - According to tests, it is found that suitable brake lining material composition would be 75% Cu, 5% Fe, 5% Sn, 5% Graphite, 5% SiO2, 5% MoS2.
Practical implications - This paper attempts to help designers choose the most proper ingredient combination for aircraft brake lining materials.
Originality/value - It has been observed that adding Silisium dioxide and Graphite forms a porositive structure. In addition, porosity brings a low strength and also high wear rate."
Nonlinear dynamic responses of a laminated hybrid composite plate subjected to time-dependent pulses are investigated. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects... more
Nonlinear dynamic responses of a laminated hybrid composite plate subjected to time-dependent pulses are investigated. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a clamped plate are assumed for the space domain. The single term approximation functions are selected by considering the nonlinear static deformation of plate obtained using the finite element method. The Galerkin Method is used to obtain the nonlinear differential equations in the time domain and a MATLAB software code is written to solve nonlinear coupled equations by using the Newmark Method. The results of approximate-numerical analysis are obtained and compared with the finite element results. Transient loading conditions considered include blast, sine, rectangular, and triangular pulses. A parametric study is conducted considering the effects of peak pressure, aspect ratio, fiber orientation and thicknesses.
The dynamic response of orthotropic sandwich composite plates impacted by time-dependent external blast pulses is studied by use of numerical techniques. The theory is based on classical sandwich plate theory including the large... more
The dynamic response of orthotropic sandwich composite plates impacted by time-dependent external blast pulses is studied by use of numerical techniques. The theory is based on classical sandwich plate theory including the large deformation effects, such as geometric non-linearities, in-plane stiffness and inertias, and shear deformation. The equations of motion for the plate are derived by the use of the virtual work principle. Approximate solutions are assumed for the space domain and substituted into the equations of motion. Then the Galerkin Method is used to obtain the non-linear differential equations in the time domain. The finite difference method is applied to solve the system of coupled non-linear equations. The results of theoretical analyses are obtained and compared with ANSYS results. Effects of the face sheet number, as well as those related to the ply-thickness, core thickness, geometrical non-linearities, and of the aspect ratio are investigated. Detailed analyses of the influence of different type of pressure pulses on dynamic response are carried out.
Research Interests: Materials Engineering, Mechanical Engineering, Civil Engineering, Aerospace Engineering, Applied Mathematics, and 17 moreFinite Element, Finite Element Analysis (FEA), Higher Order Thinking, Large Deformation Mechanics, Plate Bending, Time Dependent, Equation of Motion, Dynamic Response, Finite Difference Method, Galerkin Method, Transient Response, Time Domain, Non linear Partial Differential Equation, Linear Equations, Aspect Ratio, Degree of Freedom, and Shear deformation
This paper deals with the analysis and discussion of nonlinear dynamic response of a laminated composite plate subjected to blast load. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric... more
This paper deals with the analysis and discussion of nonlinear dynamic response of a laminated composite plate subjected to blast load. Dynamic equations of the plate are derived by the use of the virtual work principle. The geometric nonlinearity effects are taken into account with the von Kármán large deflection theory of thin plates. Approximate solutions for a simply supported plate are assumed for the space domain. The single term approximation functions are selected by considering the nonlinear static deformations of plate, which is obtained using finite element method. The Galerkin Method is used to obtain the nonlinear differential equations in the time domain. The finite difference method is applied to solve the system of coupled nonlinear equations. The results of approximate-numerical analysis are obtained and compared with the literature and finite element results. Good agreement is found for the character and frequencies of vibrations.