Papers by Luigi De Filippis
Materials, 2016
A simulation model was developed for the monitoring, controlling and optimization of the Friction... more A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration.
Materials, 2016
A study of the Friction Stir Welding (FSW) process was carried out in order to evaluate the influ... more A study of the Friction Stir Welding (FSW) process was carried out in order to evaluate the influence of process parameters on the mechanical properties of aluminum plates (AA5754-H111). The process was monitored during each test by means of infrared cameras in order to correlate temperature information with eventual changes of the mechanical properties of joints. In particular, two process parameters were considered for tests: the welding tool rotation speed and the welding tool traverse speed. The quality of joints was evaluated by means of destructive and non-destructive tests. In this regard, the presence of defects and the ultimate tensile strength (UTS) were investigated for each combination of the process parameters. A statistical analysis was carried out to assess the correlation between the thermal behavior of joints and the process parameters, also proving the capability of Infrared Thermography for on-line monitoring of the quality of joints.
Rivista Italiana della Saldatura
Advanced Knowledge Application in Practice, 2010
Proceedings of the …, 2007
Aluminium foams, produced by the powder metallurgy route, have a high potential for use in weight... more Aluminium foams, produced by the powder metallurgy route, have a high potential for use in weight-sensitive construction parts. The stiffness to weight ratio is the main criterion for material selection in lightweight design. The aim of this study is to evaluate the properties and to optimize the control factors of a powder technique, developed at the Fraunhofer Institute, starting from aluminium powders with titanium hydride as the foaming agent. During the experimental work, many samples were made following the principles of the design of experiment. Then a study of the morphology and distribution of cells and of the walls of the cells was carried out and relative density was measured. Mechanical properties of foam samples were studied by quasi-static compression tests. The final evaluation of the most important features has been made using ANOVA statistical analysis.
In this study the Taguchi method is used to find the optimal process parameters for aluminium foa... more In this study the Taguchi method is used to find the optimal process parameters for aluminium foam manufacturing. Porous metals are the unique materials used for light weight structural components, for filters and electrodes and for shock or sound absorbing products. Recently, interesting foaming technology developments have proposed metallic foams as a valid commercial chance. Metallic foam manufacturing techniques include solid state powder methods, gas blowing processes, metal deposition onto a polymer precursor and liquid state processing. The aluminium foams presented in this study are produced by the powder metallurgy route starting from aluminium powders with titanium hydride as the foaming agent. During the experimental work, many samples are made by utilizing the combination of process parameters based on Taguchi orthogonal design. Three manufacturing parameters are studied: the silicon carbide content in powder mixture, the compaction pressure and the foaming temperature. The Taguchi method is applied to design an orthogonal experimental array and a multi-objective optimization approach is then proposed by simultaneously minimizing the relative density and maximizing the absorbed energy. Verification test is also performed to prove the effectiveness of the presented technique.
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Papers by Luigi De Filippis