11 documents found, page 1 of 2
A self-clinching fastener for hidden lap joints
Sampaio, Rui F. V.; Pragana, João; Bragança, Ivo M. F; Silva, Carlos M. A.; Martins, P. A. F.This paper presents a new self-clinching fastener to connect two sheets (or plates), made from similar or dissimilar materials, placed over one another by means of a mechanical form-closed joint that is hidden inside the sheets. The development of the fastener, the definition of its main design variables and the identification of its workability limits are carried out by means of a combined experimental and num...
Hybrid wire‑arc additive manufacturing of conformal cooling channels: a feasibi...
Pragana, João; Bragança, I. M. F; Silva, C. M. A.; Martins, P. A. F.This paper investigates the feasibility of hybridizing wire-arc additive manufacturing with metal forming to create conformal cooling channels in moulds for hot material processing. An axisymmetric mould is used as a prototype test case and plastic deformation by flaring of the additively deposited inner tubular element is utilized to create the overhangs for connecting with the outer tubular element that are n...
Injection lap riveting of aluminum busbars — a thermo-electro-mechanical invest...
Pragana, J.P.M; Sampaio, Rui F. V.; Bragança, Ivo; Martins, P. A. F.This paper presents a new mechanical joining process to assemble aluminum busbars in energy distribution systems. The process is based on the extension of injection lap riveting to the connection of busbars made from the same material as the rivets and requires redesigning the joints to ensure complete filling with good mechanical interlocking and appropriate contact pressures on the overlapping area. The exper...
Formability of wire-arc deposited AISI 316L sheets for hybrid additive manufact...
Pragana, João P. M.; Bragança, Ivo; Reis, L.; Silva, Carlos M. A.; Martins, P. A. F.This paper is focused on the formability of wire-arc additively manufactured AISI 316L stainless steel sheets with the purpose of analysing the feasibility of including this material in hybrid additive manufacturing chains involving sheet metal forming operations. Conventional tensile tests performed in specimens obtained from different orientations to the building direction were carried out to characterise the...
Revisiting the ring hoop test in additively manufactured metal tubes
Pragana, João; Bragança, Ivo; Silva, Carlos; Martins, P. A. F.This paper is focussed on the mechanical and formability characterisation of wire-arc additive manufactured (WAAM) AISI 316-L stainless-steel tubes. The methodology to be presented involved carrying out tension and ring hoop tension tests on specimens extracted from the tube longitudinal, transverse and inclined directions. The force evolutions, acquired from the load cells, and the strain measurements, retriev...
Hybrid metal additive manufacturing: A state–of–the-art review
Pragana, J. P. M.; Sampaio, Rui F. V.; Bragança, Ivo; Silva, C. M. A.; Martins, P. A. F.This paper starts from the early developments and working principles of the additive manufacturing of polymers, continues with a glimpse on the extension to metals with identification and characterization of the two most widespread technologies, and ends with an overview of the recent developments in hybrid metal additive manufacturing. Earlier classifications of hybrid manufacturing with roots on the utilizati...
Invisible mechanical lap joints for metal–polymer laminates
Batista, R. J. S.; Bragança, I. M. F; Silva, C. M. A.; Pragana, J. P. M; Martins, P. A. F.Joining by compression of metallic inserts has been recently developed by the authors to create invisible lap joints between metal and polymer laminates. This paper revisits the process with the objective of proposing a new type of bi-material (polymer–metal) cylindrical insert for lightweight construction applications that is capable of ensuring complete filling of the joint at the end of stroke without increa...
Formability limits in sheet-bulk forming
Leonardo, Pedro N. C.; Magrinho, João P.; Bragança, Ivo; Silva, M. Beatriz; Silva, Carlos; Martins, P. A. F.This paper is focused on the characterization of the fracture limits in sheet-bulk forming. The approach extends to crack opening in mode III (out-of-plane shearing), a digital image correlation-based methodology for determining the fracture forming limits in mode I (tension) and mode II (in-plane shearing). For this purpose, a sheet lengthwise compression test with different end constraints is developed and ut...
Formability of a wire arc deposited aluminium alloy
Silva, C. M. A.; Bragança, Ivo; Cabrita, A.; Quintino, L.; Martins, P. A. F.This paper is focused on the formability of the aluminium alloy AA5083 deposited by wire arc additive manufacturing (WAAM). The presentation draws from metal deposition with a robotic welding system to mechanical and formability characterization by means of standard test specimens. Finite element analysis using porous metal plasticity is utilized to model strain hardening and the changes in porosity due to plas...
Joining of sheets by sheet-bulk forming: a numerical and experimental study
Bragança, Ivo; Loja, Amélia; Silva, C. M. A.; Alves, L. M.; Martins, P. A. F.The authors present a new mechanical joining process that allow to connect two sheets perpendicular to one another, a variant of the traditional ‘mortise-and-tenon’ joint. This investigation is focused on joining similar and dissimilar sheets based on sheet-bulk forming and it is supported by experimental data and numerical simulation with an in-house finite element program, I-form. Results show that is possibl...