55 documents found, page 1 of 6
Optimization of a cruciform specimen for fatigue crack growth under in and out-...
Baptista, R.; Infante, Virginia; Madeira, JFAMixed-mode loading conditions are present in different mechanical components. Understanding the influence of in-plane biaxial loading paths parameters allows for fatigue crack growth (FCG) prediction and component fatigue life assessment. Cruciform specimens are used to simulate these conditions, but large specimen dimensions are required in order to keep crack propagation unaffected by specimen geometry. This ...
Multiobjective optimization solutions for noise reduction in composite sandwich...
Araújo, A. L.; Madeira, JFAIn this paper, optimal solutions for noise reduction in laminated viscoelastic soft core sandwich plates are obtained, using active control with surface bonded piezoelectric sensors and actuators. An in–house finite element implementation of the active laminated sandwich plate is used to obtain the frequency response of the panels. Since the structural/acoustic problem is lightly coupled, the sound transmission...
Optimal distribution of active piezoelectric elements for noise attenuation in ...
Madeira, JFA; Araújo, A. L.In this paper, a multiobjective optimization approach for obtaining the optimal distribution of surface-bonded piezoelectric sensors and actuators for noise attenuation in sandwich panels is presented. The noise attenuation is achieved by using negative velocity feedback control with co-located sensors and actuators. The control gains are also optimized in order to obtain the most efficient noise attenuation in...
Optimization of a composite impact attenuator for a formula student car
Castro, J. M. P. B. C.; Fontana, M.; Araújo, Aurélio L.; Madeira, JFAThe current impact attenuator used by the Formula Student team of University of Lisbon is an out-of-shelf solution consisting in an aluminum honeycomb. The competition regulations defined for the impact attenuator’s design allow room for innovation, which can be used to build more efficient structures and explore new materials. The main objective of this work is to design and optimize a composite impact attenua...
Multiobjective optimization for vibration reduction in composite plate structur...
Madeira, JFA; Araújo, Aurélio L.; Soares, C. M. Mota; Soares, C. A. MotaThis paper presents a multiobjective optimization approach to minimize weight and maximize modal damping in laminated composite panels with Constrained Layer Damping (CLD) treatments. The design variables are the number and position of the CLD patch treatments on the surface of the laminated plate. The Direct MultiSearch (DMS) solver for multiobjective optimization problems is used in this work. DMS is a solver...
Optimization of a thin-walled composite crash absorber
Fontana, Marco; Araújo, A. L.; Madeira, JFAThis work aims to improve upon the aluminium impact attenuator currently used by the University of Lisbon Formula Student team through a composite solution. The influence of geometrical variations, particularly the use of curved walls, and the number of objectives considered for the optimization are studied. To perform the optimizations, Abaqus is coupled with the Direct Multisearch (DMS) algorithm, the overall...
Optimal passive shunted damping configurations for noise reduction in sandwich ...
Araújo, Aurélio L.; Madeira, JFAThis article addresses the issue of vibration and noise reduction in laminated sandwich plates using piezoelectric patches with passive shunted damping. A finite element implementation of a laminated sandwich plate with viscoelastic core and surface bonded piezoelectric patches is used to obtain the frequency response of the panels. The sound transmission characteristics of the panels are evaluated by computing...
Multiobjective optimization for vibration reduction in composite plate structur...
Madeira, JFA; Araújo, A. L.; Mota Soares, Cristóvão Manuel; Soares, C. A. MotaThis paper presents a multiobjective optimization approach to minimize weight and maximize modal damping in laminated composite panels with Constrained Layer Damping (CLD) treatments. The design variables are the number and position of the CLD patch treatments on the surface of the laminated plate. The Direct MultiSearch (DMS) solver for multiobjective optimization problems is used in this work. DMS is a solver...
Multi-objective optimization of pultruded composite sandwich panels for buildin...
Garrido, Mário; Madeira, JFA; Proença, M.; Correia, J. R.Composite sandwich panels are being increasingly considered for civil engineering structural applications, offering high versatility in constituent materials and their geometrical arrangement. This translates to a high number of design variables, in addition to a potentially large number of design requirements and objectives related to the panels' functions. This paper presents an optimization study of a compos...
Characterization and optimization of hybrid carbon-glass epoxy composites under...
Infante, Virginia; Madeira, JFA; Rui B. Ruben; Moleiro, Filipa; Teixeira De Freitas, SofiaThis work is intended to characterize the mechanical behavior of hybrid carbon-glass composite plates under combined loading of bending and torsion, and to determine the optimal ply fiber orientations to minimize the maximum out-of-plane displacement under such loading conditions. Hybrid composite plates were manufactured with 10 plies each and different stacking sequences using hand lay-up, with carbon fiber a...