869 research outputs found
Self piercing riveting for metal-polymer joints
No full textSelf-Piercing Riveting (SPR) is a sheet metal joining technique based on the insertion of a rivet into two or more sheets, with no preparatory hole. This process has gained wide diffusion in the automotive industry, due to the increasing use of materials alternative to steel, that are difficult or impossible to join with traditional techniques. In particular, polymeric materials are becoming increasingly used, due to their favorable weight/strength ratio. This paper reports the results of experimental investigations, aimed at identifying the variables affecting the mechanical characteristics of mixed metal-plastic joints. A statistic model for the optimization of the geometrical parameters has been computed. The paper demonstrates that self-piercing riveting appears competitive for metal/polymer junction. The results analyzed in light of statistical techniques show that some geometrical parameters affect joint performance more than others and can therefore be used as independent variables for joint performance optimizatio
Experimental and Numerical Appraisal of Self-Piercing Riveting
No full textSelf-piercing riveting (SPR) has become an interesting alternative joining technique for difficult to weld materials. A limitation of this technology is still the heavy experimental procedure needed for joint optimisation. In this paper, an experimental activity on Al6082-T4 sheet metal samples has been conducted to achieve a better understanding of the process. The joining process and the tensile tests have then been simulated using a FE code to predict deformed shape, failure mechanism (e.g. crack propagation, rivet pull-out) and shear resistance of the joint. Results show how this procedure can be a powerful tool for joint optimisatio
FEM Modeling of Self-Piercing Riveted Joint
No full texthe present paper aims at defining a numerical tool for the efficient design of the self-piercing riveting process by means of FE simulations. Abaqus Explicit v.6.4 software has been used to establish a model for 3D simulation of the joining process and of the shearing test on the riveted joint, in order to understand the joint formation and failure mechanisms. The obtained indications have been validated experimentally through joint sectioning and comparison between real geometry and numerical results. Furthermore, shear tests have been performed to compare the experimental and numerical results in terms of joint resistance
Enhancing the dimensional accuracy of a low-cost 3D printer
No full text3D printing is widely used in the entertainment industry by filmmakers, effect studios and game designers to easily and fast fabricate characters or objects that are first virtually modelled through Computer Graphics. There are several commercial proposals in the field of low-cost 3D printers, with prices starting from a few hundred euros for kits that the users should assemble by themselves. However, their performances in terms of part accuracy are quite limited and are basically the consequence of a lack of optimization both in mechanical terms as in software. Starting from these considerations, an optimization project was assigned to the students of the Specializing Master in Industrial Automation of the Politecnico di Torino. The Master is developed in collaboration with COMAU S.p.a., a company worldwide leader in automation expecially for the automotive sector. The task of enhancing the performances of the 3D printer Prusa i3, that is supplied in the assembly box, was assigned to sixteen engineers attending the Master who were divided into 4 groups. The activities have led to the birth of four new 3D printers: Fluo, Ghost, Metallica and Print-Doh. In order to assess and validate the improvements, a benchmarking activity was carried out to evaluate the dimensional accuracy of the four printers. The benchmarking was based on the manufacturing of an innovative reference artifact whose geometrical features are designed to fit within different ISO basic sizes. Each group printed a replica of the reference part with their own new printer and then the replicas were measured by means of a coordinate measuring machine (CMM). Measures were used to compare the performances of the four printers and the results of the benchmarking considers the dimensional accuracy of the replicas in terms of ISO IT grades, but also the form errors of the geometrical features through GD&T tolerances
Simulazione del processo di colata: scelta del software
No full textGREAT 2020 (GReen Engine for Air Transport in 2020) - LIFT (LIght & saFe design soluTion laboratory) - Virtual Design e Manufacturing (OR3) - Documento M.3.3.
Macro-scale machining simulation model, nickel
No full textVERDI (Virtual Engineering for Robust manufacturing with Design Integration) Deliverable Report 3.7.4.
Sensitivity analysis of model parameters on finite element simulation of orthogonal cutting
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