Ali Al-Bahi | King AbdulAziz University (KAU) Jeddah, Saudi Arabia (original) (raw)

Papers by Ali Al-Bahi

2018 Annual Reliability and Maintainability Symposium (RAMS), 2018

In this paper, more than thirty years of local operational field data were used to predict and va... more In this paper, more than thirty years of local operational field data were used to predict and validate the failure rate of the Lockheed C-130 (T-56) Turbine with respect to turbine life data in hours (t) using both Weibull and lognormal regression models. By using Weibull Analysis on (MS Excel), the data was fitted into the model using two parameters, a good straight line fit to the transformed data is supporting the validity of the Weibull model. Furthermore, a validation of our MS Excel spreadsheet format of Weibull analysis was compared with the result obtained from Weibull and lognormal regression using Weibull++7.

The purpose of this paper is to present a preliminary design of a mini unmanned aerial vehicle. T... more The purpose of this paper is to present a preliminary design of a mini unmanned aerial vehicle. The design itself was based on the requirement of an international universities competition sponsored the national office for studies and researches of aerospace sciences ONERA-FRANCE (Office National d'Etudes et de Recherches Aerospatiales). For complying with competition regulations the UAV should not exceed 70 cm in any dimensions, and capable of flying outside the direct field of vision of its pilot. The vehicle is intended to be used as aid to infantry troops located in hostile territory. The intended aid function is of a non-aggressive nature. Its purpose is to provide an extension to the nature field of vision of the infantry soldier.

2023 Annual Reliability and Maintainability Symposium (RAMS)

The objective of this research is to assess the reliability characteristics of the Allison T-56 a... more The objective of this research is to assess the reliability characteristics of the Allison T-56 aircraft turbine system which is subjected to local GCC environment where sand erosion is a major factor in reducing turbine life. To utilize this study, mor than thirty years of local fielded data were used for failure rate prediction and validation. The work utilizes Artificial Neural Networks (ANN) employing feed-forward Back-Propagation (BP) and Radial Basis Functions (RBF) neural network algorithm to predict the general T-56 engine turbine failure rate and the failures which required an overhaul maintenance, The results show that the failure times predicted by the RBF model. is closer in agreement with actual failure date than BP model. By the end of the study, we forecast the general failure rate of T-56 Engine Turbine, the failures which required overhaul maintenance and six categorical failures using Multilayer Perceptron neural network (MLP) model on DTREG commercial software. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

European Journal of Engineering Education, 2011

ABSTRACT A project-based active/cooperative design course is planned, implemented, assessed and e... more ABSTRACT A project-based active/cooperative design course is planned, implemented, assessed and evaluated to achieve several desired engineering outcomes. The course allows freshman-level students to gain professional hands-on engineering design experience through an opportunity to practise teamwork, quality principles, communication skills, life-long learning, realistic constraints and awareness of current domestic and global challenges. Throughout successive design reports and in-class assignments, the students are required by the end of the semester to communicate, clearly and concisely, the details of their design both orally and in writing through a functional artefact/prototype, a design notebook, an A0 project poster and a final oral presentation. In addition to these direct assessment tools, several indirect measures are used to ensure triangulation. Assignments are based on customer expectations using a detailed checklist. This paper shows the direct and indirect assessment tools that indicated a high level of achievement of course learning outcomes and a high level of student satisfaction.

2021 Annual Reliability and Maintainability Symposium (RAMS)

The C-130 aircraft is one of the most widely used medium transports in the world. It operates vir... more The C-130 aircraft is one of the most widely used medium transports in the world. It operates virtually everywhere, from the arctic circle to the Sahara. Operation in desert conditions, however, presents a challenge for maintenance engineers regarding preventive maintenance scheduling. Erosion caused by sand particles drastically decreases turbine blades life. Recent studies showed that Artificial Neural Network ANN algorithms have much better capability at modeling reliability and predicting failure than conventional algorithms. In this study, more than thirty years of local operational field data were used for failure rate prediction and validation using several algorithms. These include Weibull regression modeling to establish a reference, feed-forward back-propagation ANN, and radial basis neural network algorithm. Comparison between the three methods is carried out. Results show that the failure rate predicted by both the feed-forward back-propagation artificial neural network model and radial basis neural network model are closer to actual failure data than he failure rate predicted by the Weibull model. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

Journal of Aeronautics, Astronautics and Aviation, 2021

Air sand erosion is a widely affecting phenomenon in the Gulf Cooperation Council (GCC) region, w... more Air sand erosion is a widely affecting phenomenon in the Gulf Cooperation Council (GCC) region, where a solid particle impacts a wall surface, causing catastrophic damage to the engine compressor. Operation in such a harsh environment is subjected to performance and life deterioration due to sand ingestion. In the present paper, the effect of air sand erosion on transonic compressors is addressed. Flow rate, particle size, and particle concentration are selected as parameters to predict the effect of erosion rate and particle distribution on and along with the compressor blades.
Results show that particle concentration has the most significant effect on blade erosion rate, and particle size has the least effect among all other measured parameters. Surface deformation and roughness are in scope for further investigation.

A general formulation of the inverse problem of aircraft control is presented. The trajectory of ... more A general formulation of the inverse problem of aircraft control is presented. The trajectory of the prescribed maneuver is modeled as a set of dynamic constrahts on the general non linear equations of motion. The equations are directly integrated to obtain the control vector necessary to realize the prescribed maneuver. The problem is also considered for the case of a trajectory described by a succession of defined points. A smoothing interpolation technique is used to approximate the trajectory in order to insure the continuity of all path derivatives. These continuous path derivatives, with respect to the path arc length parameter, are obtained .numerically and substituted in the analytic expressions of the generalized velocities and accelerations. The method is applied to some interesting plane as well as spatial flight maneuvers.

International Journal of Modelling and Simulation, 1993

A computer model to study the response of an aircraft to disturbances of control elements is pres... more A computer model to study the response of an aircraft to disturbances of control elements is presented. . The general nondimensional small disturbance equations of motion are obtained in the form of linearized first-order differential equations. The equations are wri tten in vector form, and are denoted as the state equation. The Ztransform is used to obtain the recursion relation, which is the solution of the state equation. The numerical model is used to provide an illustration for airplane response to various simulated control faults during maneuvering or straight flight. It is concluded from the study that disturbances of the three control elements tend to activate several aircraft stabili ty modes , some of which may be unstable. In addition, the fault configuration seems to have a clear effect on the aircraft response within the fault-time domain.

SUMMARY In order to enhance the ongoing preparations of different engineering programs for ABET E... more SUMMARY In order to enhance the ongoing preparations of different engineering programs for ABET EC2000 accreditation, several colleges are encouraging transforming basic engineering courses into active cooperative learning environment. The introductory fluid mechanics course represents a good candidate for such transformation because it is a mandatory course for several engineering programs. The fluid mechanics course under consideration in the present work is a 4-credit, 6-contact hours course and enrols about 1٢0 students in 5 sections per semester. The course was redesigned and delivered during the last semester for one section only in order to compare results and evaluate the experience with respect to the other four sections having classical lectures but using data shows and power point presentations. The new course design reflected the 5 pillars of active cooperative learning, namely; positive interdependence, individual accountability, face to face interaction, social coopera...

International Journal of Modelling and Simulation, 1993

A general formulation of the inverse problem of how to control an airplane when it is performing ... more A general formulation of the inverse problem of how to control an airplane when it is performing a prescribed maneuver is presented. The general nonlinear equations of the forced motion of a rigid airplane are written in terms of generali zed coordinates. The trajectory of the prescribed maneuver is modeled as a set of dynamic constraints on the previous equations. The equations are directly integrated to obtain the control vector necessary to realize the prescribed maneuver. An app lication to a fighter aircraft circularloop simulation is studied as a special case of the proposed technique.

International Conference on Aerospace Sciences and Aviation Technology, 1993

A method based on the vorticity stream function formulation is used for the solution of the unste... more A method based on the vorticity stream function formulation is used for the solution of the unsteady incompressible two-dimensional laminar viscous flow problems. Vorticity transport and stream function equations are written in generalized curvilinear non-orthogonal coordinate system, and discretized using an implicit finite difference approximation. A second order accurate scheme with a stabilizing correction splitting method as an ADI technique is used. Both conservative and non-conservative forms of the vorticity transport equation are considered and the problems associated with different treatments of boundary conditions are addressed. Several test cases, including rectangular cavity flow problem, flow around circular cylinder and flow past an isolated airfoil at moderate angles of attack, are illustrated.

International Conference on Aerospace Sciences and Aviation Technology, 1993

An experimental study was conducted to investigate the effect of trailing vortices on a strake-wi... more An experimental study was conducted to investigate the effect of trailing vortices on a strake-wing-body configuration. This configuration was placed trailing a large rectangular leading wing of NACA 0015 airfoil section. The angle of attack of the leading wing was varied to obtain variable induced trailing vortices. The lift, drag and side forces in addition to the yawing, pitching and rolling moments were measured for the trailing configuration at different values of incidence and bank angles. Analysis of the experimental results shows a drop in lift, a slight influence on drag, and practically no effect on the longitudinal stability. In order to maintain the same lift, the results demonstrated that it is imperative to increase the angle of attack which consequently increases the drag and adds a smaller nose-down pitching moment. A negative rolling moment is produced for this symmetric tailless configuration for zero bank angle. During banking flight a small positive yawing moment and a negative side force are produced.

21st Atmospheric Flight Mechanics Conference, 1996

Control input histories that insure safe turbulence penetration and preserve prescribed flight pa... more Control input histories that insure safe turbulence penetration and preserve prescribed flight path in the presence of atmospheric disturbances are determined using the inverse simulation technique. Only a local knowledge of the wind field about the aircraft is required such that the method can be used with forward-looking airborne systems for real-time control of the aircraft. The expected response if the pilot maintains the no-disturbance control law is also investigated. Numerical results are presented for a fighter aircraft executing a straight-loop-straight maneuver in a vertical plane. (Author)

34th Aerospace Sciences Meeting and Exhibit, 1996

An efficient finite difference algorithm for the solution of unsteady incompressible viscous flow... more An efficient finite difference algorithm for the solution of unsteady incompressible viscous flow problems is presented. The algorithm is based on the numerical solution of the unsteady Navier Stokes equations in primitive variables. The numerical approach is based on artificial compressibility and dual-time stepping. The driven flow in a square cavity is selected as a model problem to test the proposed numerical scheme. (Author)

International Conference on Aerospace Sciences and Aviation Technology, 1993

The aerodynamic characteristics of a tailless Strake-Wing-Body configuration are studied experime... more The aerodynamic characteristics of a tailless Strake-Wing-Body configuration are studied experimentally in a low speed wind tunnel. The model is mounted on a six component sting wind tunnel balance system to measure longitudinal and lateral forces and moments. Both sideslip and bank angles are varied independently for angles of attack up to 20 degrees. The effect of freestream Reynolds number is also considered. The study reveals that the strake vortex tends to delay wing vortex breakdown caused by small variations in sideslip and/or banking angles. Meanwhile, large lateral manoeuvres at low speeds must be executed at high angles of attack in order to compensate the loss in the lift coefficient. The study also demonstrates that the bank angle slightly degrades the stability margin and displaces the equilibrium point towards negative lift coefficients. The sideslip angle adds a constant negative side force, a positive yawing moment at low angles of attack and a negative yawing moment at high angles of attack. Also a negative stabilizing rolling moment is added by the bank and sideslip angles at moderate and high angles of attack.

IEEE, 2023

The objective of this research is to assess the reliability characteristics of the Allison T-56 a... more The objective of this research is to assess the reliability characteristics of the Allison T-56 aircraft turbine system which is subjected to local GCC environment where sand erosion is a major factor in reducing turbine life. To utilize this study, mor than thirty years of local fielded data were used for failure rate prediction and validation. The work utilizes Artificial Neural Networks (ANN) employing feed-forward Back-Propagation (BP) and Radial Basis Functions (RBF) neural network algorithm to predict the general T-56 engine turbine failure rate and the failures which required an overhaul maintenance, The results show that the failure times predicted by the RBF model. is closer in agreement with actual failure date than BP model. By the end of the study, we forecast the general failure rate of T-56 Engine Turbine, the failures which required overhaul maintenance and six categorical failures using Multilayer Perceptron neural network (MLP) model on DTREG commercial software. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

International Journal of Modern Physics B

In this paper, to characterize the appearances of bio-convection and influencing microorganisms i... more In this paper, to characterize the appearances of bio-convection and influencing microorganisms in movements of influenced Walters-B nanofluid, we built a process in a stretchable sheet utilizing Fourier’s and Fick’s laws. The mass and temperature diffusion hypothesis proposed by Cattaneo and Christov has been considered. Also, the Buongiorno phenomenon for nanofluid wave in the Walters-B fluid is used, according to the Cattaneo–Christov connection. A system of regulating partial differential equations (PDEs) is transformed into ordinary differential equations (ODEs) using similarity transformations. Due to the Galerkin finite element mode, the software COMSOL is utilized to derive mathematical solutions for nonlinear equations (G-FEM). Temperature, velocity, and microorganism analysis are all investigated using logical and pictorial metrics. Nanoparticle concentrations are also calculated by considering various approximations of well-known physical characteristics. The simulations ...

2021 Annual Reliability and Maintainability Symposium (RAMS), 2021

FMEA was used to analyze the failure modes, causes, and effects of the T-56 engine turbine. Failu... more FMEA was used to analyze the failure modes, causes, and effects of the T-56 engine turbine. Failure location and contributing factors were identified and categorized. To give an insight into risk assessment and priority for corrective action, FMEA data were ranked using RPN ranking. From the FMEA matrix, the major failure mode of the T-56 engine turbine was found to be the mechanical damage due to structural failure caused by different factors like erosion and sand ingestion. On the other hand, field data capture the operational and environmental stresses associated with the actual usage conditions and allows for more accurate predictions of the reliability performance of the components. This enables the operators to develop appropriate inspection or replacement programs, and spare part plans based on their own operational and environmental conditions, which result in decreasing maintenance costs and minimizing flight delays and cancellations due to unexpected failures.

2018 Annual Reliability and Maintainability Symposium (RAMS), 2018

In this paper, more than thirty years of local operational field data were used to predict and va... more In this paper, more than thirty years of local operational field data were used to predict and validate the failure rate of the Lockheed C-130 (T-56) Turbine with respect to turbine life data in hours (t) using both Weibull and lognormal regression models. By using Weibull Analysis on (MS Excel), the data was fitted into the model using two parameters, a good straight line fit to the transformed data is supporting the validity of the Weibull model. Furthermore, a validation of our MS Excel spreadsheet format of Weibull analysis was compared with the result obtained from Weibull and lognormal regression using Weibull++7.

The purpose of this paper is to present a preliminary design of a mini unmanned aerial vehicle. T... more The purpose of this paper is to present a preliminary design of a mini unmanned aerial vehicle. The design itself was based on the requirement of an international universities competition sponsored the national office for studies and researches of aerospace sciences ONERA-FRANCE (Office National d'Etudes et de Recherches Aerospatiales). For complying with competition regulations the UAV should not exceed 70 cm in any dimensions, and capable of flying outside the direct field of vision of its pilot. The vehicle is intended to be used as aid to infantry troops located in hostile territory. The intended aid function is of a non-aggressive nature. Its purpose is to provide an extension to the nature field of vision of the infantry soldier.

2023 Annual Reliability and Maintainability Symposium (RAMS)

The objective of this research is to assess the reliability characteristics of the Allison T-56 a... more The objective of this research is to assess the reliability characteristics of the Allison T-56 aircraft turbine system which is subjected to local GCC environment where sand erosion is a major factor in reducing turbine life. To utilize this study, mor than thirty years of local fielded data were used for failure rate prediction and validation. The work utilizes Artificial Neural Networks (ANN) employing feed-forward Back-Propagation (BP) and Radial Basis Functions (RBF) neural network algorithm to predict the general T-56 engine turbine failure rate and the failures which required an overhaul maintenance, The results show that the failure times predicted by the RBF model. is closer in agreement with actual failure date than BP model. By the end of the study, we forecast the general failure rate of T-56 Engine Turbine, the failures which required overhaul maintenance and six categorical failures using Multilayer Perceptron neural network (MLP) model on DTREG commercial software. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

European Journal of Engineering Education, 2011

ABSTRACT A project-based active/cooperative design course is planned, implemented, assessed and e... more ABSTRACT A project-based active/cooperative design course is planned, implemented, assessed and evaluated to achieve several desired engineering outcomes. The course allows freshman-level students to gain professional hands-on engineering design experience through an opportunity to practise teamwork, quality principles, communication skills, life-long learning, realistic constraints and awareness of current domestic and global challenges. Throughout successive design reports and in-class assignments, the students are required by the end of the semester to communicate, clearly and concisely, the details of their design both orally and in writing through a functional artefact/prototype, a design notebook, an A0 project poster and a final oral presentation. In addition to these direct assessment tools, several indirect measures are used to ensure triangulation. Assignments are based on customer expectations using a detailed checklist. This paper shows the direct and indirect assessment tools that indicated a high level of achievement of course learning outcomes and a high level of student satisfaction.

2021 Annual Reliability and Maintainability Symposium (RAMS)

The C-130 aircraft is one of the most widely used medium transports in the world. It operates vir... more The C-130 aircraft is one of the most widely used medium transports in the world. It operates virtually everywhere, from the arctic circle to the Sahara. Operation in desert conditions, however, presents a challenge for maintenance engineers regarding preventive maintenance scheduling. Erosion caused by sand particles drastically decreases turbine blades life. Recent studies showed that Artificial Neural Network ANN algorithms have much better capability at modeling reliability and predicting failure than conventional algorithms. In this study, more than thirty years of local operational field data were used for failure rate prediction and validation using several algorithms. These include Weibull regression modeling to establish a reference, feed-forward back-propagation ANN, and radial basis neural network algorithm. Comparison between the three methods is carried out. Results show that the failure rate predicted by both the feed-forward back-propagation artificial neural network model and radial basis neural network model are closer to actual failure data than he failure rate predicted by the Weibull model. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

Journal of Aeronautics, Astronautics and Aviation, 2021

Air sand erosion is a widely affecting phenomenon in the Gulf Cooperation Council (GCC) region, w... more Air sand erosion is a widely affecting phenomenon in the Gulf Cooperation Council (GCC) region, where a solid particle impacts a wall surface, causing catastrophic damage to the engine compressor. Operation in such a harsh environment is subjected to performance and life deterioration due to sand ingestion. In the present paper, the effect of air sand erosion on transonic compressors is addressed. Flow rate, particle size, and particle concentration are selected as parameters to predict the effect of erosion rate and particle distribution on and along with the compressor blades.
Results show that particle concentration has the most significant effect on blade erosion rate, and particle size has the least effect among all other measured parameters. Surface deformation and roughness are in scope for further investigation.

A general formulation of the inverse problem of aircraft control is presented. The trajectory of ... more A general formulation of the inverse problem of aircraft control is presented. The trajectory of the prescribed maneuver is modeled as a set of dynamic constrahts on the general non linear equations of motion. The equations are directly integrated to obtain the control vector necessary to realize the prescribed maneuver. The problem is also considered for the case of a trajectory described by a succession of defined points. A smoothing interpolation technique is used to approximate the trajectory in order to insure the continuity of all path derivatives. These continuous path derivatives, with respect to the path arc length parameter, are obtained .numerically and substituted in the analytic expressions of the generalized velocities and accelerations. The method is applied to some interesting plane as well as spatial flight maneuvers.

International Journal of Modelling and Simulation, 1993

A computer model to study the response of an aircraft to disturbances of control elements is pres... more A computer model to study the response of an aircraft to disturbances of control elements is presented. . The general nondimensional small disturbance equations of motion are obtained in the form of linearized first-order differential equations. The equations are wri tten in vector form, and are denoted as the state equation. The Ztransform is used to obtain the recursion relation, which is the solution of the state equation. The numerical model is used to provide an illustration for airplane response to various simulated control faults during maneuvering or straight flight. It is concluded from the study that disturbances of the three control elements tend to activate several aircraft stabili ty modes , some of which may be unstable. In addition, the fault configuration seems to have a clear effect on the aircraft response within the fault-time domain.

SUMMARY In order to enhance the ongoing preparations of different engineering programs for ABET E... more SUMMARY In order to enhance the ongoing preparations of different engineering programs for ABET EC2000 accreditation, several colleges are encouraging transforming basic engineering courses into active cooperative learning environment. The introductory fluid mechanics course represents a good candidate for such transformation because it is a mandatory course for several engineering programs. The fluid mechanics course under consideration in the present work is a 4-credit, 6-contact hours course and enrols about 1٢0 students in 5 sections per semester. The course was redesigned and delivered during the last semester for one section only in order to compare results and evaluate the experience with respect to the other four sections having classical lectures but using data shows and power point presentations. The new course design reflected the 5 pillars of active cooperative learning, namely; positive interdependence, individual accountability, face to face interaction, social coopera...

International Journal of Modelling and Simulation, 1993

A general formulation of the inverse problem of how to control an airplane when it is performing ... more A general formulation of the inverse problem of how to control an airplane when it is performing a prescribed maneuver is presented. The general nonlinear equations of the forced motion of a rigid airplane are written in terms of generali zed coordinates. The trajectory of the prescribed maneuver is modeled as a set of dynamic constraints on the previous equations. The equations are directly integrated to obtain the control vector necessary to realize the prescribed maneuver. An app lication to a fighter aircraft circularloop simulation is studied as a special case of the proposed technique.

International Conference on Aerospace Sciences and Aviation Technology, 1993

A method based on the vorticity stream function formulation is used for the solution of the unste... more A method based on the vorticity stream function formulation is used for the solution of the unsteady incompressible two-dimensional laminar viscous flow problems. Vorticity transport and stream function equations are written in generalized curvilinear non-orthogonal coordinate system, and discretized using an implicit finite difference approximation. A second order accurate scheme with a stabilizing correction splitting method as an ADI technique is used. Both conservative and non-conservative forms of the vorticity transport equation are considered and the problems associated with different treatments of boundary conditions are addressed. Several test cases, including rectangular cavity flow problem, flow around circular cylinder and flow past an isolated airfoil at moderate angles of attack, are illustrated.

International Conference on Aerospace Sciences and Aviation Technology, 1993

An experimental study was conducted to investigate the effect of trailing vortices on a strake-wi... more An experimental study was conducted to investigate the effect of trailing vortices on a strake-wing-body configuration. This configuration was placed trailing a large rectangular leading wing of NACA 0015 airfoil section. The angle of attack of the leading wing was varied to obtain variable induced trailing vortices. The lift, drag and side forces in addition to the yawing, pitching and rolling moments were measured for the trailing configuration at different values of incidence and bank angles. Analysis of the experimental results shows a drop in lift, a slight influence on drag, and practically no effect on the longitudinal stability. In order to maintain the same lift, the results demonstrated that it is imperative to increase the angle of attack which consequently increases the drag and adds a smaller nose-down pitching moment. A negative rolling moment is produced for this symmetric tailless configuration for zero bank angle. During banking flight a small positive yawing moment and a negative side force are produced.

21st Atmospheric Flight Mechanics Conference, 1996

Control input histories that insure safe turbulence penetration and preserve prescribed flight pa... more Control input histories that insure safe turbulence penetration and preserve prescribed flight path in the presence of atmospheric disturbances are determined using the inverse simulation technique. Only a local knowledge of the wind field about the aircraft is required such that the method can be used with forward-looking airborne systems for real-time control of the aircraft. The expected response if the pilot maintains the no-disturbance control law is also investigated. Numerical results are presented for a fighter aircraft executing a straight-loop-straight maneuver in a vertical plane. (Author)

34th Aerospace Sciences Meeting and Exhibit, 1996

An efficient finite difference algorithm for the solution of unsteady incompressible viscous flow... more An efficient finite difference algorithm for the solution of unsteady incompressible viscous flow problems is presented. The algorithm is based on the numerical solution of the unsteady Navier Stokes equations in primitive variables. The numerical approach is based on artificial compressibility and dual-time stepping. The driven flow in a square cavity is selected as a model problem to test the proposed numerical scheme. (Author)

International Conference on Aerospace Sciences and Aviation Technology, 1993

The aerodynamic characteristics of a tailless Strake-Wing-Body configuration are studied experime... more The aerodynamic characteristics of a tailless Strake-Wing-Body configuration are studied experimentally in a low speed wind tunnel. The model is mounted on a six component sting wind tunnel balance system to measure longitudinal and lateral forces and moments. Both sideslip and bank angles are varied independently for angles of attack up to 20 degrees. The effect of freestream Reynolds number is also considered. The study reveals that the strake vortex tends to delay wing vortex breakdown caused by small variations in sideslip and/or banking angles. Meanwhile, large lateral manoeuvres at low speeds must be executed at high angles of attack in order to compensate the loss in the lift coefficient. The study also demonstrates that the bank angle slightly degrades the stability margin and displaces the equilibrium point towards negative lift coefficients. The sideslip angle adds a constant negative side force, a positive yawing moment at low angles of attack and a negative yawing moment at high angles of attack. Also a negative stabilizing rolling moment is added by the bank and sideslip angles at moderate and high angles of attack.

IEEE, 2023

The objective of this research is to assess the reliability characteristics of the Allison T-56 a... more The objective of this research is to assess the reliability characteristics of the Allison T-56 aircraft turbine system which is subjected to local GCC environment where sand erosion is a major factor in reducing turbine life. To utilize this study, mor than thirty years of local fielded data were used for failure rate prediction and validation. The work utilizes Artificial Neural Networks (ANN) employing feed-forward Back-Propagation (BP) and Radial Basis Functions (RBF) neural network algorithm to predict the general T-56 engine turbine failure rate and the failures which required an overhaul maintenance, The results show that the failure times predicted by the RBF model. is closer in agreement with actual failure date than BP model. By the end of the study, we forecast the general failure rate of T-56 Engine Turbine, the failures which required overhaul maintenance and six categorical failures using Multilayer Perceptron neural network (MLP) model on DTREG commercial software. The results also give an insight into the reliability of the engine turbine under actual operating conditions, which can be used by aircraft operators for assessing system and component failures and customizing the maintenance programs recommended by the manufacturer.

International Journal of Modern Physics B

In this paper, to characterize the appearances of bio-convection and influencing microorganisms i... more In this paper, to characterize the appearances of bio-convection and influencing microorganisms in movements of influenced Walters-B nanofluid, we built a process in a stretchable sheet utilizing Fourier’s and Fick’s laws. The mass and temperature diffusion hypothesis proposed by Cattaneo and Christov has been considered. Also, the Buongiorno phenomenon for nanofluid wave in the Walters-B fluid is used, according to the Cattaneo–Christov connection. A system of regulating partial differential equations (PDEs) is transformed into ordinary differential equations (ODEs) using similarity transformations. Due to the Galerkin finite element mode, the software COMSOL is utilized to derive mathematical solutions for nonlinear equations (G-FEM). Temperature, velocity, and microorganism analysis are all investigated using logical and pictorial metrics. Nanoparticle concentrations are also calculated by considering various approximations of well-known physical characteristics. The simulations ...

2021 Annual Reliability and Maintainability Symposium (RAMS), 2021

FMEA was used to analyze the failure modes, causes, and effects of the T-56 engine turbine. Failu... more FMEA was used to analyze the failure modes, causes, and effects of the T-56 engine turbine. Failure location and contributing factors were identified and categorized. To give an insight into risk assessment and priority for corrective action, FMEA data were ranked using RPN ranking. From the FMEA matrix, the major failure mode of the T-56 engine turbine was found to be the mechanical damage due to structural failure caused by different factors like erosion and sand ingestion. On the other hand, field data capture the operational and environmental stresses associated with the actual usage conditions and allows for more accurate predictions of the reliability performance of the components. This enables the operators to develop appropriate inspection or replacement programs, and spare part plans based on their own operational and environmental conditions, which result in decreasing maintenance costs and minimizing flight delays and cancellations due to unexpected failures.