Luis Falcao - Academia.edu (original) (raw)
Papers by Luis Falcao
51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference<BR> 18th AIAA/ASME/AHS Adaptive Structures Conference<BR> 12th, 2010
research project involving three university partners from the UK, Portugal and Italy. The aim of ... more research project involving three university partners from the UK, Portugal and Italy. The aim of the project is to develop novel structural concepts and implementations of morphing aeroelastic structures. An overview of the current status of the project is provided, including description of the development, modelling and design optimization of several morphing aeroelastic structures. Reference will also be made to the design, manufacture and testing of wind tunnel and RPV demonstrator models.
Application of multistable composites to adaptive aircraft structures has been limited, not only ... more Application of multistable composites to adaptive aircraft structures has been limited, not only because of the very recent development of these materials but also because the simplest plate geometries and layer stacking sequences originate plates whose stable shapes are of little interest to morphing aircraft components. This paper focuses on the development and optimisation of alternative multistable composite plate configurations for application to morphing wingtips. Since morphing wingtips inherently combine structural and aerodynamic effects, multidisciplinary optimisation (MDO) is a fundamental step in the design of adequate, efficient components. The requirements and MDO strategy for the problem of morphing wingtips are presented.
51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference<BR> 18th AIAA/ASME/AHS Adaptive Structures Conference<BR> 12th, 2010
research project involving three university partners from the UK, Portugal and Italy. The aim of ... more research project involving three university partners from the UK, Portugal and Italy. The aim of the project is to develop novel structural concepts and implementations of morphing aeroelastic structures. An overview of the current status of the project is provided, including description of the development, modelling and design optimization of several morphing aeroelastic structures. Reference will also be made to the design, manufacture and testing of wind tunnel and RPV demonstrator models.
52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 2011
Wingtip devices are a common component of most modern aircraft, improving the overall aerodynamic... more Wingtip devices are a common component of most modern aircraft, improving the overall aerodynamic behaviour of the wing and thus improving performance and reducing operating costs and pollutant emissions. Unfortunately, given the wide range of different flight conditions encountered ...
54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2013
Journal of Intelligent Material Systems and Structures, 2011
Computers & Structures, 2008
Economic and environmental factors have spurred major advances in the development of more economi... more Economic and environmental factors have spurred major advances in the development of more economical and greener aircraft. Nevertheless, an important limitation stems from the need for an aircraft to perform highly dissimilar tasks throughout the flight. If an aircraft were able to morph so as to adapt to each moment’s requirements, it could assume the most efficient configuration for each task, increasing its capabilities and reducing its consumption and environmental impact. This thesis explores that concept, presenting an adaptive wingtip device mechanism that takes advantage of the wingtip device’s combination of high aerodynamic influence and small size to develop a system with low cost, energy requirements and complexity but possessing significant gains in different flight stages. The detailed design of the mechanism is presented, as are computational models and optimisation algorithms that allowed the analysis of this mechanism and its comparison with conventional wingtip devices. The results show gains in different flight stages, reaching a maximum of approximately 15% reduction in take-off distance. The energy balance and emissions reduction are also quantified. The results obtained lead to the conclusion that the proposed mechanism shows great promise and finally key aspects for further development are outlined.
Keywords: Wingtip; winglet; morphing; adaptive structure; multidisciplinary design optimisation; multistable composites
The hydraulic brakes presently used in cars exhibit several important limitations. These include ... more The hydraulic brakes presently used in cars exhibit several important limitations. These include the slow response to the driver’s command; difficulties in control due to the hydraulic nature of the system; and a large number of components spread throughout the car with critical components such as the disk surface, the brake pads and the fluid pipings vulnerable to damage from gravel or other external sources. To overcome these problems, intrinsic to the concept of hydraulic brakes, a new system must be devised. Solutions are sought in the use of smart materials, including the application of piezoelectric or electrostrictive materials and electrorheological or magnetorheological fluids to car brakes. A detailed study of each material is carried out, in terms of their possibilities and limitations. It is seen that present piezoelectric and electrostrictive materials are unable to meet the performance requirements needed for application to car brakes and that electrorheological fluids are less suitable than magnetorheolical fluids for this application. Consequently, an innovative car braking system is designed using magnetorheological fluids.
The design procedure comprises the study of theoretical models for the performance of a magnetorheological brake and, given the absence of closed-form solutions for the braking torque of an arbitrary brake system, finite element models are built to provide a means to analyse the performance of the magnetorheological brake system. The formulation of these models (including the definition of the geometry, material properties, boundary conditions and meshing process, as well as necessary assumptions) are described. The results obtained with the finite element models are presented and analysed.
In order to obtain an optimum design, i.e. one with high braking power and low weight, an optimisation procedure is carried out, centred on the finite element analysis. Three different optimisation methods are used (subproblem approximation, first order and simulated annealing). Their performance and relative methods are compared.
Based on the results of the optimisation problem, a final design is proposed, taking into account manufacturing constraints and a study of its longevity and reliability is carried out. A scaled-down prototype is also proposed to serve as a proof of concept.
Finally, the strengths and weaknesses of magnetorheological brakes and the expected evolution of this techonology are discussed, as well as conclusions regarding the use of piezoelectric or electrostrictive materials for brake actuators.
51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference<BR> 18th AIAA/ASME/AHS Adaptive Structures Conference<BR> 12th, 2010
research project involving three university partners from the UK, Portugal and Italy. The aim of ... more research project involving three university partners from the UK, Portugal and Italy. The aim of the project is to develop novel structural concepts and implementations of morphing aeroelastic structures. An overview of the current status of the project is provided, including description of the development, modelling and design optimization of several morphing aeroelastic structures. Reference will also be made to the design, manufacture and testing of wind tunnel and RPV demonstrator models.
Application of multistable composites to adaptive aircraft structures has been limited, not only ... more Application of multistable composites to adaptive aircraft structures has been limited, not only because of the very recent development of these materials but also because the simplest plate geometries and layer stacking sequences originate plates whose stable shapes are of little interest to morphing aircraft components. This paper focuses on the development and optimisation of alternative multistable composite plate configurations for application to morphing wingtips. Since morphing wingtips inherently combine structural and aerodynamic effects, multidisciplinary optimisation (MDO) is a fundamental step in the design of adequate, efficient components. The requirements and MDO strategy for the problem of morphing wingtips are presented.
51st AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference<BR> 18th AIAA/ASME/AHS Adaptive Structures Conference<BR> 12th, 2010
research project involving three university partners from the UK, Portugal and Italy. The aim of ... more research project involving three university partners from the UK, Portugal and Italy. The aim of the project is to develop novel structural concepts and implementations of morphing aeroelastic structures. An overview of the current status of the project is provided, including description of the development, modelling and design optimization of several morphing aeroelastic structures. Reference will also be made to the design, manufacture and testing of wind tunnel and RPV demonstrator models.
52nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, 2011
Wingtip devices are a common component of most modern aircraft, improving the overall aerodynamic... more Wingtip devices are a common component of most modern aircraft, improving the overall aerodynamic behaviour of the wing and thus improving performance and reducing operating costs and pollutant emissions. Unfortunately, given the wide range of different flight conditions encountered ...
54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2013
Journal of Intelligent Material Systems and Structures, 2011
Computers & Structures, 2008
Economic and environmental factors have spurred major advances in the development of more economi... more Economic and environmental factors have spurred major advances in the development of more economical and greener aircraft. Nevertheless, an important limitation stems from the need for an aircraft to perform highly dissimilar tasks throughout the flight. If an aircraft were able to morph so as to adapt to each moment’s requirements, it could assume the most efficient configuration for each task, increasing its capabilities and reducing its consumption and environmental impact. This thesis explores that concept, presenting an adaptive wingtip device mechanism that takes advantage of the wingtip device’s combination of high aerodynamic influence and small size to develop a system with low cost, energy requirements and complexity but possessing significant gains in different flight stages. The detailed design of the mechanism is presented, as are computational models and optimisation algorithms that allowed the analysis of this mechanism and its comparison with conventional wingtip devices. The results show gains in different flight stages, reaching a maximum of approximately 15% reduction in take-off distance. The energy balance and emissions reduction are also quantified. The results obtained lead to the conclusion that the proposed mechanism shows great promise and finally key aspects for further development are outlined.
Keywords: Wingtip; winglet; morphing; adaptive structure; multidisciplinary design optimisation; multistable composites
The hydraulic brakes presently used in cars exhibit several important limitations. These include ... more The hydraulic brakes presently used in cars exhibit several important limitations. These include the slow response to the driver’s command; difficulties in control due to the hydraulic nature of the system; and a large number of components spread throughout the car with critical components such as the disk surface, the brake pads and the fluid pipings vulnerable to damage from gravel or other external sources. To overcome these problems, intrinsic to the concept of hydraulic brakes, a new system must be devised. Solutions are sought in the use of smart materials, including the application of piezoelectric or electrostrictive materials and electrorheological or magnetorheological fluids to car brakes. A detailed study of each material is carried out, in terms of their possibilities and limitations. It is seen that present piezoelectric and electrostrictive materials are unable to meet the performance requirements needed for application to car brakes and that electrorheological fluids are less suitable than magnetorheolical fluids for this application. Consequently, an innovative car braking system is designed using magnetorheological fluids.
The design procedure comprises the study of theoretical models for the performance of a magnetorheological brake and, given the absence of closed-form solutions for the braking torque of an arbitrary brake system, finite element models are built to provide a means to analyse the performance of the magnetorheological brake system. The formulation of these models (including the definition of the geometry, material properties, boundary conditions and meshing process, as well as necessary assumptions) are described. The results obtained with the finite element models are presented and analysed.
In order to obtain an optimum design, i.e. one with high braking power and low weight, an optimisation procedure is carried out, centred on the finite element analysis. Three different optimisation methods are used (subproblem approximation, first order and simulated annealing). Their performance and relative methods are compared.
Based on the results of the optimisation problem, a final design is proposed, taking into account manufacturing constraints and a study of its longevity and reliability is carried out. A scaled-down prototype is also proposed to serve as a proof of concept.
Finally, the strengths and weaknesses of magnetorheological brakes and the expected evolution of this techonology are discussed, as well as conclusions regarding the use of piezoelectric or electrostrictive materials for brake actuators.