Unique Objects (UNOs) are relevant for real-world applications such as anti-counterfeiting system... more Unique Objects (UNOs) are relevant for real-world applications such as anti-counterfeiting systems. In this work, cork is demonstrated as a UNO, part of the Physical Unclonability and Disorder (PUD) system. An adequate measurement kit (illumination device) and recognition method are also devised and evaluated. Natural hills and valleys of the cork are enhanced using the illumination device and the overall robustness of the recognition application inherent to UNOs is presented. The lighting device is based on grazing light and the recognition task is based on a local feature detector and descriptor called ORB - Oriented FAST (Features from Accelerated Segment Test) and Rotated BRIEF (Binary Robust Independent Elementary Features). The performance evaluation utilizes a private cork database (1500 photos of 500 cork stoppers) and three public iris databases. In the tests carried out on the illumination device, the results clearly show the success of capturing stable/repeatable features...
Functionally graded material (FGM) based on Inconel 625 and AISI 431 stainless steel powders was ... more Functionally graded material (FGM) based on Inconel 625 and AISI 431 stainless steel powders was produced by applying the direct laser deposition (DLD) process. The FGM starts with layers of Inconel 625 and ends with layers of 431 stainless steel having three intermediate zones with the composition (100-X)% Inconel 625-X% 431 stainless steel, X = 25, 50, and 75, in that order. This FGM was deposited on a 42CrMo4 steel substrate, with and without preheating. Microstructures of these FGMs were evaluated, while considering the distribution of chemical composition and grain structure. Microstructures mainly consisted of columnar grains independent of preheating condition; epitaxial growth was observed. The application of a non-preheated substrate caused the formation of planar grains in the vicinity of the substrate. In addition, hardness maps were produced. The hardness distribution across these FGMs confirmed a smooth transition between deposited layers; however, the heat-affected zon...
The fabrication of digital prostheses has acquired growing importance not only for the possibilit... more The fabrication of digital prostheses has acquired growing importance not only for the possibility for the patient to overcome psychosocial trauma but also to promote grip functionality. An application method of three dimensional-computer-aided design technologies for the production of passive prostheses is presented by means of a fifth finger amputee clinical case following bilateral hand replantation.Three-dimensional-computerized tomography was used for the collection of anthropometric images of the hands. Computer-aided design techniques were used to develop the digital file-based prosthesis from the reconstruction images by inversion and superimposing the contra-lateral finger images. The rapid prototyping manufacturing method was used for the production of a silicone bandage prosthesis prototype. This approach replaces the traditional manual method by a virtual method that is basis for the optimization of a high speed, accurate and innovative process.
Glocalized Solutions for Sustainability in Manufacturing - Proceedings of the 18th CIRP International Conference on Life Cycle Engineering, 2011
Abstract This paper presents the results of a comparison between a simplified LCA analysis and a ... more Abstract This paper presents the results of a comparison between a simplified LCA analysis and a detailed LCA carried out under a Ecodesign project of a machine-tool, a commercial CNC press-brake. The aim was to assess to what degree, the most detailed information ...
This paper introduces a framework for the Ecodesign of sheet metal cutters, which targets the def... more This paper introduces a framework for the Ecodesign of sheet metal cutters, which targets the definition of a set of design guidelines for this type of machine-tools, based on the contribution of the main equipment sub-systems to the processing and environmental impacts associated to their electrical energy consumption. A comparative study of commercially available Laser cutting equipments, using CO2 or doped fiber as the energy source, is described. Two parallel analysis of electricity consumption have been carried out: (1) the observation of CO2-Laser cutters usage, production modes and work conditions in real industrial environments, and (2) a comparison between these and a Fiber-Laser equipment, for a similar work order (material and thickness). The specific process energy with the different equipments was calculated, and confirms the importance of alternative technologies and practices for the energy efficiency of machining processes.
In the present paper, an EMF numerical model has been developed following an uncoupled approach, ... more In the present paper, an EMF numerical model has been developed following an uncoupled approach, being the Lorentz forces acting on the workpiece estimated by solving Maxwells equations and then transferred to solve the mechanical problem. For formability analysis, a fracture indicator based on the linear forming limit diagram was applied through the use of a post-processing tool developed by the authors. To illustrate the applicability of the implemented code in the fracture prediction, an example of electromagnetic tube expansion is presented. The corresponding numerical simulation is performed and its results are compared with experimental obtained from literature for a selected material.
The last decade has witnessed many advances and a lot of improvement in FE codes for simulation o... more The last decade has witnessed many advances and a lot of improvement in FE codes for simulation of sheet metal forming processes. Such advances could be followed mainly by benchmarks proposed in Numisheet conferences. It was possible to notice that the scatter of results among numerical codes has decreased so signi®cantly that recently scattering of experimental results among different corporations was evident. However in order to pursue further developments and validate numerical results it is fundamental to have reliable reference experimental data. This is one of the objectives of a current IMS project called 3DS-Digital Die Design System. In this paper such objectives are presented as well as some of the proposed benchmarks. It is intended to show part of the developed work concerning tool design and manufacturing methodology. Also an experimental case study about the use of piercing holes in parts and the use of counter-punch is presented. Finally some simulation results are also shown concerning one of the proposed benchmarks.
The selection of the best material combination for a part involves a high number of parameters as... more The selection of the best material combination for a part involves a high number of parameters associated with the technologies used in industry. Sheet metal forming technology is widely used to obtain different type of parts. In these processes a large amount of plastic deformation ...
The selection of the best material combination for a part involves a high number of parameters as... more The selection of the best material combination for a part involves a high number of parameters associated with the technologies used in industry. Sheet metal forming technology is widely used to obtain different type of parts. In these processes a large amount of plastic deformation ...
The last decade has witnessed many advances and a lot of improvement in FE codes for simulation o... more The last decade has witnessed many advances and a lot of improvement in FE codes for simulation of sheet metal forming processes. Such advances could be followed mainly by benchmarks proposed in Numisheet conferences. It was possible to notice that the scatter of results among ...
Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industri... more Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industrial areas due to its low material waste and fast stacking speed to fabricate high performance products. The present contribution addresses several known challenges including mechanical behaviour and porosity analysis on directed energy deposition (DED) manufactured stainless steel 316L components. The experimental methodology consisting of metal deposition procedure, hardness testing and fractographic observations on manufactured mini-tensile test samples is described. A ductile fracture material model based on the Rousselier damage criterion is utilized within a FE framework for evaluation of material global response and determination of initial porosity value representing the structure’s nucleating void population. Alternatively, the initial pore sizes are characterized using the generalized mixture rule (GMR) analysis and the validity of the approach is examined against the experimenta...
Unique Objects (UNOs) are relevant for real-world applications such as anti-counterfeiting system... more Unique Objects (UNOs) are relevant for real-world applications such as anti-counterfeiting systems. In this work, cork is demonstrated as a UNO, part of the Physical Unclonability and Disorder (PUD) system. An adequate measurement kit (illumination device) and recognition method are also devised and evaluated. Natural hills and valleys of the cork are enhanced using the illumination device and the overall robustness of the recognition application inherent to UNOs is presented. The lighting device is based on grazing light and the recognition task is based on a local feature detector and descriptor called ORB - Oriented FAST (Features from Accelerated Segment Test) and Rotated BRIEF (Binary Robust Independent Elementary Features). The performance evaluation utilizes a private cork database (1500 photos of 500 cork stoppers) and three public iris databases. In the tests carried out on the illumination device, the results clearly show the success of capturing stable/repeatable features...
Functionally graded material (FGM) based on Inconel 625 and AISI 431 stainless steel powders was ... more Functionally graded material (FGM) based on Inconel 625 and AISI 431 stainless steel powders was produced by applying the direct laser deposition (DLD) process. The FGM starts with layers of Inconel 625 and ends with layers of 431 stainless steel having three intermediate zones with the composition (100-X)% Inconel 625-X% 431 stainless steel, X = 25, 50, and 75, in that order. This FGM was deposited on a 42CrMo4 steel substrate, with and without preheating. Microstructures of these FGMs were evaluated, while considering the distribution of chemical composition and grain structure. Microstructures mainly consisted of columnar grains independent of preheating condition; epitaxial growth was observed. The application of a non-preheated substrate caused the formation of planar grains in the vicinity of the substrate. In addition, hardness maps were produced. The hardness distribution across these FGMs confirmed a smooth transition between deposited layers; however, the heat-affected zon...
The fabrication of digital prostheses has acquired growing importance not only for the possibilit... more The fabrication of digital prostheses has acquired growing importance not only for the possibility for the patient to overcome psychosocial trauma but also to promote grip functionality. An application method of three dimensional-computer-aided design technologies for the production of passive prostheses is presented by means of a fifth finger amputee clinical case following bilateral hand replantation.Three-dimensional-computerized tomography was used for the collection of anthropometric images of the hands. Computer-aided design techniques were used to develop the digital file-based prosthesis from the reconstruction images by inversion and superimposing the contra-lateral finger images. The rapid prototyping manufacturing method was used for the production of a silicone bandage prosthesis prototype. This approach replaces the traditional manual method by a virtual method that is basis for the optimization of a high speed, accurate and innovative process.
Glocalized Solutions for Sustainability in Manufacturing - Proceedings of the 18th CIRP International Conference on Life Cycle Engineering, 2011
Abstract This paper presents the results of a comparison between a simplified LCA analysis and a ... more Abstract This paper presents the results of a comparison between a simplified LCA analysis and a detailed LCA carried out under a Ecodesign project of a machine-tool, a commercial CNC press-brake. The aim was to assess to what degree, the most detailed information ...
This paper introduces a framework for the Ecodesign of sheet metal cutters, which targets the def... more This paper introduces a framework for the Ecodesign of sheet metal cutters, which targets the definition of a set of design guidelines for this type of machine-tools, based on the contribution of the main equipment sub-systems to the processing and environmental impacts associated to their electrical energy consumption. A comparative study of commercially available Laser cutting equipments, using CO2 or doped fiber as the energy source, is described. Two parallel analysis of electricity consumption have been carried out: (1) the observation of CO2-Laser cutters usage, production modes and work conditions in real industrial environments, and (2) a comparison between these and a Fiber-Laser equipment, for a similar work order (material and thickness). The specific process energy with the different equipments was calculated, and confirms the importance of alternative technologies and practices for the energy efficiency of machining processes.
In the present paper, an EMF numerical model has been developed following an uncoupled approach, ... more In the present paper, an EMF numerical model has been developed following an uncoupled approach, being the Lorentz forces acting on the workpiece estimated by solving Maxwells equations and then transferred to solve the mechanical problem. For formability analysis, a fracture indicator based on the linear forming limit diagram was applied through the use of a post-processing tool developed by the authors. To illustrate the applicability of the implemented code in the fracture prediction, an example of electromagnetic tube expansion is presented. The corresponding numerical simulation is performed and its results are compared with experimental obtained from literature for a selected material.
The last decade has witnessed many advances and a lot of improvement in FE codes for simulation o... more The last decade has witnessed many advances and a lot of improvement in FE codes for simulation of sheet metal forming processes. Such advances could be followed mainly by benchmarks proposed in Numisheet conferences. It was possible to notice that the scatter of results among numerical codes has decreased so signi®cantly that recently scattering of experimental results among different corporations was evident. However in order to pursue further developments and validate numerical results it is fundamental to have reliable reference experimental data. This is one of the objectives of a current IMS project called 3DS-Digital Die Design System. In this paper such objectives are presented as well as some of the proposed benchmarks. It is intended to show part of the developed work concerning tool design and manufacturing methodology. Also an experimental case study about the use of piercing holes in parts and the use of counter-punch is presented. Finally some simulation results are also shown concerning one of the proposed benchmarks.
The selection of the best material combination for a part involves a high number of parameters as... more The selection of the best material combination for a part involves a high number of parameters associated with the technologies used in industry. Sheet metal forming technology is widely used to obtain different type of parts. In these processes a large amount of plastic deformation ...
The selection of the best material combination for a part involves a high number of parameters as... more The selection of the best material combination for a part involves a high number of parameters associated with the technologies used in industry. Sheet metal forming technology is widely used to obtain different type of parts. In these processes a large amount of plastic deformation ...
The last decade has witnessed many advances and a lot of improvement in FE codes for simulation o... more The last decade has witnessed many advances and a lot of improvement in FE codes for simulation of sheet metal forming processes. Such advances could be followed mainly by benchmarks proposed in Numisheet conferences. It was possible to notice that the scatter of results among ...
Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industri... more Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industrial areas due to its low material waste and fast stacking speed to fabricate high performance products. The present contribution addresses several known challenges including mechanical behaviour and porosity analysis on directed energy deposition (DED) manufactured stainless steel 316L components. The experimental methodology consisting of metal deposition procedure, hardness testing and fractographic observations on manufactured mini-tensile test samples is described. A ductile fracture material model based on the Rousselier damage criterion is utilized within a FE framework for evaluation of material global response and determination of initial porosity value representing the structure’s nucleating void population. Alternatively, the initial pore sizes are characterized using the generalized mixture rule (GMR) analysis and the validity of the approach is examined against the experimenta...
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