In this study derived differential equations are examined by using one of the famous Finite Eleme... more In this study derived differential equations are examined by using one of the famous Finite Element Method (FEM) i.e. Galerkin’s method under given boundary conditions. The flow in the pipe is considered to be periodic and moves transversely towards the walls of the pipe. It has been observed that this type of flow movement in the vessel may cause dynamic instability at the boundaries or cause sudden failure. The results obtained from Galerkin’s method is compared with the exact solution and found good in agreement between the two results.
A specially designed apparatus and circuit working on the principle of inverse piezoelectricity d... more A specially designed apparatus and circuit working on the principle of inverse piezoelectricity due to the effect of polarization was used to find the relationship between resistance and peak to peak voltage of Lead Zirconate Titanate (PZT-5A4E) by shocking it at variable frequencies and at variable resistances under various thermal conditions within Curie temperature limit using equivalent circuit method. It was found that by increasing temperature, peak to peak voltage increases and similarly by increasing frequency, peak to peak voltage decreases and with the increase in resistance peak to peak voltage decreases.
This research is concerned with analytical modelling of the effects of cracks in structural plate... more This research is concerned with analytical modelling of the effects of cracks in structural plates and panels within aerospace systems such as aeroplane fuselage, wing, and tail-plane structures, and, as such, is part of a larger body of research into damage detection methodologies in such systems. This study is based on generating a so-called reduced order analytical model of the behaviour of the plate panel, within which a crack with some arbitrary characteristics is present, and which is subjected to a force that causes it to vibrate. In practice such a scenario is potentially extremely dangerous as it can lead to failure, with obvious consequences. The equation that is obtained is in the form of the classical Duffing equation, in this case, the coefficients within the equation contain information about the geometrical and mass properties of the plate, the loading and boundary conditions, and the geometry, location, and potentially the orientation of the crack. This equation has ...
A specially designed apparatus and circuit working on the principle of inverse piezoelectricity d... more A specially designed apparatus and circuit working on the principle of inverse piezoelectricity due to the effect of polarization was used to find the relationship between resistance and peak to peak voltage of Lead Zirconate Titanate (PZT-5A4E)by shocking it at variable frequencies and at variable resistances under various thermal conditions within Curie temperature limit using equivalent circuit method. It was found that by increasing temperature, peak to peak voltage increases and similarly by increasing frequency, peak to peak voltage decreases and with the increase in resistance peak to peak voltage decreases.
In this study derived differential equations are examined by using one of the famous Finite Eleme... more In this study derived differential equations are examined by using one of the famous Finite Element Method (FEM) i.e. Galerkin’s method under given boundary conditions. The flow in the pipe is considered to be periodic and moves transversely towards the walls of the pipe. It has been observed that this type of flow movement in the vessel may cause dynamic instability at the boundaries or cause sudden failure. The results obtained from Galerkin’s method is compared with the exact solution and found good in agreement between the two results.
2013 International Conference on Aerospace Science & Engineering (ICASE), 2013
ABSTRACT This study presents one of the methodologies that can be adopted to design variable wing... more ABSTRACT This study presents one of the methodologies that can be adopted to design variable wing geometry and its functionality. With this concept the aircraft is able to perform optimally under a variety of flight conditions. The major aspects discussed include the basic geometry design of a double delta aircraft for initial sizing, the selection and importance of the correct airfoil for the selected geometry and lastly how to find the pivot point for the variable wing mechanism that produces least overlapping issues. In addition, 3D modeling tool in Pro Eng is used to verify the results of selected airfoil. The results indicate a better overall performance for both flight regimes of subsonic and supersonic.
This paper presents design, modeling, and analysis of satellite model used for remote sensing. A ... more This paper presents design, modeling, and analysis of satellite model used for remote sensing. A detailed study is carried out for the design and modeling of the satellite structure focusing on the factors such as the selection of material, optimization of shape and geometry, and accommodation of different subsystems and payload. The center of mass is required to be kept within the range of (1-2) cm from its geometric center. Once the model is finalized it is required to be analyzed by the use of Ansys, a tool for finite element analysis (FEA) under given loading and boundary conditions. Static, modal, and harmonic analyses in Ansys are performed at the time of ground testing and launching phase. The finite element analysis results are also validated and compared with the theoretical predictions. These analyses are quite helpful and suggest that the satellite structure does not fail and retains its structural integrity during launch environment.
In this paper the nonlinear vibration of an aircraft panel structure modelled as an isotropic cra... more In this paper the nonlinear vibration of an aircraft panel structure modelled as an isotropic cracked plate and subjected to transverse harmonic excitation is considered for studying the dynamic response, both analytically and experimentally. A crack is arbitrarily located at the centre of the plate, consisting of a continuous line. This mathematical model is in the form of Duffing equation with a cubic nonlinear term. The perturbation method of multiple scales is used to solve the algebraic equation, and then investigated with the results of the direct integration within Mathematica™ and finite element analysis in ABAQUS for the first mode only. In addition, experimental measurements are also carried out to verify the dependence of the cracked plate's fundamental mode shape and resonance frequency on the vibration displacement amplitude. An extermely close agreement between these results is observed.
Arkadiusz (2009) Analytical modelling and vibration analysis of cracked rectangular plates with d... more Arkadiusz (2009) Analytical modelling and vibration analysis of cracked rectangular plates with different loading and boundary conditions.
In this paper a theoretical relationship for the effective thermal conductivity of a multiphase t... more In this paper a theoretical relationship for the effective thermal conductivity of a multiphase transversely isotropic composite system is obtained. The Generalized Self-Consistent Method and simple energy balance principle is employed to derive a more appropriate model. In the derivation, it is assumed that the orientation of fiber within the transversely isotropic composite system is unidirectional and surrounded by two different phases of porous and matrix phase. A combined effect of these three different phases on the effective thermal conductivity of the composite system in transverse direction is studied. The effect of the interfacial contact conductance between the fibers and porous medium is also considered. Results of effective thermal conductivity are plotted against volume fraction and conductance which shows extremely good agreement.
Abstract Recent NATO funded research on methods for detection and interpretation methodologies fo... more Abstract Recent NATO funded research on methods for detection and interpretation methodologies for damage detection in aircraft panel structures has motivated work on low-order nonlinear analytical modelling of vibrations in cracked isotropic plates, typically in the form of aluminium aircraft panels. The work applies fundamental aspects of fracture mechanics to define an elliptical crack, and the local stress field and loading conditions, arbitrarily located at some point in the plate, and then derives an analytical expression for ...
Abstract In this paper weight optimization of sandwich structure consisting of a honeycomb core s... more Abstract In this paper weight optimization of sandwich structure consisting of a honeycomb core sandwiched between two layers is presented through the use of Sequential Quadratic Programming & Genetic Algorithm by constraining of certain parameters such as buckling ...
Abstract This particular work consider a pressurized vessel typically made of high strength low a... more Abstract This particular work consider a pressurized vessel typically made of high strength low alloy steel and containing the geometric misalignment at the cylinder-to-cylinder junction. This misalignment produce in the vessel's structure is because of girth weld that ...
This study proposes an analytical model for vibrations in a cracked rectangular plate as one of t... more This study proposes an analytical model for vibrations in a cracked rectangular plate as one of the results from a programme of research on vibration based damage detection in aircraft panel structures. This particular work considers an isotropic plate, typically made of aluminium, and containing a crack in the form of a continuous line with its centre located at the centre of the plate, and parallel to one edge of the plate. The plate is subjected to a point load on its surface for three different possible boundary conditions, and one examined in detail. Galerkin's method is applied to reformulate the governing equation of the cracked plate into time dependent modal coordinates. Nonlinearity is introduced by appropriate formulations introduced by applying Berger's method. An approximate solution technique, the method of multiple scales, is applied to solve the nonlinear equation of the cracked plate. Results are presented in terms of natural frequency versus crack length and plate thickness, and the nonlinear amplitude response of the plate is calculated for one set of boundary conditions and three different load locations, over a practical range of external excitation frequencies.
In this study derived differential equations are examined by using one of the famous Finite Eleme... more In this study derived differential equations are examined by using one of the famous Finite Element Method (FEM) i.e. Galerkin’s method under given boundary conditions. The flow in the pipe is considered to be periodic and moves transversely towards the walls of the pipe. It has been observed that this type of flow movement in the vessel may cause dynamic instability at the boundaries or cause sudden failure. The results obtained from Galerkin’s method is compared with the exact solution and found good in agreement between the two results.
A specially designed apparatus and circuit working on the principle of inverse piezoelectricity d... more A specially designed apparatus and circuit working on the principle of inverse piezoelectricity due to the effect of polarization was used to find the relationship between resistance and peak to peak voltage of Lead Zirconate Titanate (PZT-5A4E) by shocking it at variable frequencies and at variable resistances under various thermal conditions within Curie temperature limit using equivalent circuit method. It was found that by increasing temperature, peak to peak voltage increases and similarly by increasing frequency, peak to peak voltage decreases and with the increase in resistance peak to peak voltage decreases.
This research is concerned with analytical modelling of the effects of cracks in structural plate... more This research is concerned with analytical modelling of the effects of cracks in structural plates and panels within aerospace systems such as aeroplane fuselage, wing, and tail-plane structures, and, as such, is part of a larger body of research into damage detection methodologies in such systems. This study is based on generating a so-called reduced order analytical model of the behaviour of the plate panel, within which a crack with some arbitrary characteristics is present, and which is subjected to a force that causes it to vibrate. In practice such a scenario is potentially extremely dangerous as it can lead to failure, with obvious consequences. The equation that is obtained is in the form of the classical Duffing equation, in this case, the coefficients within the equation contain information about the geometrical and mass properties of the plate, the loading and boundary conditions, and the geometry, location, and potentially the orientation of the crack. This equation has ...
A specially designed apparatus and circuit working on the principle of inverse piezoelectricity d... more A specially designed apparatus and circuit working on the principle of inverse piezoelectricity due to the effect of polarization was used to find the relationship between resistance and peak to peak voltage of Lead Zirconate Titanate (PZT-5A4E)by shocking it at variable frequencies and at variable resistances under various thermal conditions within Curie temperature limit using equivalent circuit method. It was found that by increasing temperature, peak to peak voltage increases and similarly by increasing frequency, peak to peak voltage decreases and with the increase in resistance peak to peak voltage decreases.
In this study derived differential equations are examined by using one of the famous Finite Eleme... more In this study derived differential equations are examined by using one of the famous Finite Element Method (FEM) i.e. Galerkin’s method under given boundary conditions. The flow in the pipe is considered to be periodic and moves transversely towards the walls of the pipe. It has been observed that this type of flow movement in the vessel may cause dynamic instability at the boundaries or cause sudden failure. The results obtained from Galerkin’s method is compared with the exact solution and found good in agreement between the two results.
2013 International Conference on Aerospace Science & Engineering (ICASE), 2013
ABSTRACT This study presents one of the methodologies that can be adopted to design variable wing... more ABSTRACT This study presents one of the methodologies that can be adopted to design variable wing geometry and its functionality. With this concept the aircraft is able to perform optimally under a variety of flight conditions. The major aspects discussed include the basic geometry design of a double delta aircraft for initial sizing, the selection and importance of the correct airfoil for the selected geometry and lastly how to find the pivot point for the variable wing mechanism that produces least overlapping issues. In addition, 3D modeling tool in Pro Eng is used to verify the results of selected airfoil. The results indicate a better overall performance for both flight regimes of subsonic and supersonic.
This paper presents design, modeling, and analysis of satellite model used for remote sensing. A ... more This paper presents design, modeling, and analysis of satellite model used for remote sensing. A detailed study is carried out for the design and modeling of the satellite structure focusing on the factors such as the selection of material, optimization of shape and geometry, and accommodation of different subsystems and payload. The center of mass is required to be kept within the range of (1-2) cm from its geometric center. Once the model is finalized it is required to be analyzed by the use of Ansys, a tool for finite element analysis (FEA) under given loading and boundary conditions. Static, modal, and harmonic analyses in Ansys are performed at the time of ground testing and launching phase. The finite element analysis results are also validated and compared with the theoretical predictions. These analyses are quite helpful and suggest that the satellite structure does not fail and retains its structural integrity during launch environment.
In this paper the nonlinear vibration of an aircraft panel structure modelled as an isotropic cra... more In this paper the nonlinear vibration of an aircraft panel structure modelled as an isotropic cracked plate and subjected to transverse harmonic excitation is considered for studying the dynamic response, both analytically and experimentally. A crack is arbitrarily located at the centre of the plate, consisting of a continuous line. This mathematical model is in the form of Duffing equation with a cubic nonlinear term. The perturbation method of multiple scales is used to solve the algebraic equation, and then investigated with the results of the direct integration within Mathematica™ and finite element analysis in ABAQUS for the first mode only. In addition, experimental measurements are also carried out to verify the dependence of the cracked plate's fundamental mode shape and resonance frequency on the vibration displacement amplitude. An extermely close agreement between these results is observed.
Arkadiusz (2009) Analytical modelling and vibration analysis of cracked rectangular plates with d... more Arkadiusz (2009) Analytical modelling and vibration analysis of cracked rectangular plates with different loading and boundary conditions.
In this paper a theoretical relationship for the effective thermal conductivity of a multiphase t... more In this paper a theoretical relationship for the effective thermal conductivity of a multiphase transversely isotropic composite system is obtained. The Generalized Self-Consistent Method and simple energy balance principle is employed to derive a more appropriate model. In the derivation, it is assumed that the orientation of fiber within the transversely isotropic composite system is unidirectional and surrounded by two different phases of porous and matrix phase. A combined effect of these three different phases on the effective thermal conductivity of the composite system in transverse direction is studied. The effect of the interfacial contact conductance between the fibers and porous medium is also considered. Results of effective thermal conductivity are plotted against volume fraction and conductance which shows extremely good agreement.
Abstract Recent NATO funded research on methods for detection and interpretation methodologies fo... more Abstract Recent NATO funded research on methods for detection and interpretation methodologies for damage detection in aircraft panel structures has motivated work on low-order nonlinear analytical modelling of vibrations in cracked isotropic plates, typically in the form of aluminium aircraft panels. The work applies fundamental aspects of fracture mechanics to define an elliptical crack, and the local stress field and loading conditions, arbitrarily located at some point in the plate, and then derives an analytical expression for ...
Abstract In this paper weight optimization of sandwich structure consisting of a honeycomb core s... more Abstract In this paper weight optimization of sandwich structure consisting of a honeycomb core sandwiched between two layers is presented through the use of Sequential Quadratic Programming & Genetic Algorithm by constraining of certain parameters such as buckling ...
Abstract This particular work consider a pressurized vessel typically made of high strength low a... more Abstract This particular work consider a pressurized vessel typically made of high strength low alloy steel and containing the geometric misalignment at the cylinder-to-cylinder junction. This misalignment produce in the vessel's structure is because of girth weld that ...
This study proposes an analytical model for vibrations in a cracked rectangular plate as one of t... more This study proposes an analytical model for vibrations in a cracked rectangular plate as one of the results from a programme of research on vibration based damage detection in aircraft panel structures. This particular work considers an isotropic plate, typically made of aluminium, and containing a crack in the form of a continuous line with its centre located at the centre of the plate, and parallel to one edge of the plate. The plate is subjected to a point load on its surface for three different possible boundary conditions, and one examined in detail. Galerkin's method is applied to reformulate the governing equation of the cracked plate into time dependent modal coordinates. Nonlinearity is introduced by appropriate formulations introduced by applying Berger's method. An approximate solution technique, the method of multiple scales, is applied to solve the nonlinear equation of the cracked plate. Results are presented in terms of natural frequency versus crack length and plate thickness, and the nonlinear amplitude response of the plate is calculated for one set of boundary conditions and three different load locations, over a practical range of external excitation frequencies.
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