Asif Israr | Institute of Space Technology (original) (raw)

Papers by Asif Israr

Research paper thumbnail of Transverse Flow of Periodic Pressure Waves in Vessel

Journal of Space Technology

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.

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Research paper thumbnail of Experimental Determination of Effect of Variable Resistance on Lead Zirconate Titanate (PZT-5A4E) under various Thermal and Frequency Conditions

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Research paper thumbnail of Vibration Analysis of Cracked Aluminium Plates

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 ...

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Research paper thumbnail of Wing Tip Kinematics of Ornithopters

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Research paper thumbnail of Cracked Isotropic Plate Structures–A Review

Journal of Space Technology

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Research paper thumbnail of Experimental Determination of Effect of Variable Resistance on Lead Zirconate Titanate (PZT-5A4E) under various Thermal and Frequency Conditions

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.

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Research paper thumbnail of Transverse Flow of Periodic Pressure Waves in Vessel

Journal of Space Technology

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.

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Research paper thumbnail of Dynamical System Analysis from Nonlinear Transiton to Chaos for a Cracked Plate)

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Research paper thumbnail of Propagation of elastic waves in pre-stressed elements of structures

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Research paper thumbnail of An Empirical Relationship to Predict Damages in Carbon Fiber Reinforced Composites under Extreme Thermal Cycling Conditions

Key Engineering Materials, 2012

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Research paper thumbnail of Methodologies for preliminary design of variable wing geometry aircraft

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.

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Research paper thumbnail of Vibration and Modal Analysis of Low Earth Orbit Satellite

Shock and Vibration, 2014

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Research paper thumbnail of Investigation of the nonlinear dynamics of a partially cracked plate

Journal of Physics: Conference Series, 2009

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Research paper thumbnail of Analytical Modeling and Vibration Analysis of Partially Cracked Rectangular Plates With Different Boundary Conditions and Loading

Journal of Applied Mechanics, 2009

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Research paper thumbnail of An Analytical Modeling for Effective Thermal Conductivity of Multi-Phase Transversely Isotropic Fiberous Composites Using Generalized Self-Consistent Method

Applied Mechanics and Materials, 2012

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Research paper thumbnail of On Approximate Analytical Solutions for Vibrations in Cracked Plates

Applied Mechanics and Materials, 2006

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 ...

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Research paper thumbnail of An Integrated Approach for Optimization of Honeycomb Sandwich Structure under Impact Load

Applied Mechanics and Materials, 2012

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 ...

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Research paper thumbnail of To Analyze the Effects of Geometric Misalignment in a Cylindrical Pressure Vessel

Applied Mechanics and Materials, 2012

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 ...

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Research paper thumbnail of Analytical modelling and vibration analysis of cracked rectangular plates with different loading and boundary conditions

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Research paper thumbnail of Transverse Flow of Periodic Pressure Waves in Vessel

Journal of Space Technology

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.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Experimental Determination of Effect of Variable Resistance on Lead Zirconate Titanate (PZT-5A4E) under various Thermal and Frequency Conditions

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Vibration Analysis of Cracked Aluminium Plates

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 ...

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Research paper thumbnail of Wing Tip Kinematics of Ornithopters

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Research paper thumbnail of Cracked Isotropic Plate Structures–A Review

Journal of Space Technology

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Research paper thumbnail of Experimental Determination of Effect of Variable Resistance on Lead Zirconate Titanate (PZT-5A4E) under various Thermal and Frequency Conditions

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.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Transverse Flow of Periodic Pressure Waves in Vessel

Journal of Space Technology

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.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dynamical System Analysis from Nonlinear Transiton to Chaos for a Cracked Plate)

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Propagation of elastic waves in pre-stressed elements of structures

Bookmarks Related papers MentionsView impact

Research paper thumbnail of An Empirical Relationship to Predict Damages in Carbon Fiber Reinforced Composites under Extreme Thermal Cycling Conditions

Key Engineering Materials, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Methodologies for preliminary design of variable wing geometry aircraft

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.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Vibration and Modal Analysis of Low Earth Orbit Satellite

Shock and Vibration, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Investigation of the nonlinear dynamics of a partially cracked plate

Journal of Physics: Conference Series, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Analytical Modeling and Vibration Analysis of Partially Cracked Rectangular Plates With Different Boundary Conditions and Loading

Journal of Applied Mechanics, 2009

Bookmarks Related papers MentionsView impact

Research paper thumbnail of An Analytical Modeling for Effective Thermal Conductivity of Multi-Phase Transversely Isotropic Fiberous Composites Using Generalized Self-Consistent Method

Applied Mechanics and Materials, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of On Approximate Analytical Solutions for Vibrations in Cracked Plates

Applied Mechanics and Materials, 2006

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 ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of An Integrated Approach for Optimization of Honeycomb Sandwich Structure under Impact Load

Applied Mechanics and Materials, 2012

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 ...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of To Analyze the Effects of Geometric Misalignment in a Cylindrical Pressure Vessel

Applied Mechanics and Materials, 2012

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 ...

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Research paper thumbnail of Analytical modelling and vibration analysis of cracked rectangular plates with different loading and boundary conditions

Bookmarks Related papers MentionsView impact