55 documents found, page 1 of 6
Enhancing the performance of double-flush riveted joints through hybridization ...
Alpendre, João M. B.; Rosado, Pedro M. S.; Sampaio, Rui F. V.; Pragana, João P. M.; Bragança, Ivo; Silva, Carlos M. A.; Martins, Paulo A. F.This paper explores the potential to enhance the mechanical performance of joints created through a new joining-by-forming technique called hybrid double-flush riveting. To achieve this, adhesive bonding is used to form hybrid lap joints with superior mechanical properties. The study focuses on high-strength steel sheets and starts by identifying the appropriate surface conditions necessary for producing strong...
On the enhancement of material formability in hybrid wire arc additive manufact...
Pragana, João; Brito, Beatriz; Bragança, Ivo; Silva, Carlos; Martins, PauloThis paper is focused on improving material formability in hybrid wire-arc additive manufacturing comprising metal forming stages to produce small-to-medium batches of customized parts. The methodology involves fabricating wire arc additive manufactured AISI 316L stainless steel parts subjected to mechanical and thermal processing (MTP), followed by microhardness measurements, tensile testing with digital image...
Multi-planar injection lap riveting
Sapage, Miguel S. T.; Pragana, João P. M.; Sampaio, Rui F.V.; Bragança, Ivo; Silva, Carlos M. A.; Martins, PauloThis paper is focused on multi-planar hybrid busbars made from copper and aluminum for electric energy distribution systems. The objective is to provide an overview of its assembly by injection lap riveting in multidirectional tools and to compare the electrical performance of its joints against that of conventional (in-plane) busbars. The injected lap riveted joints require a dovetail ring hole and a countersu...
Joining by forming of bi-material collector coins with rotating elements
Rosado, Pedro M. S.; Sampaio, Rui F.V.; Pragana, João P. M.; Bragança, Ivo; Silva, Carlos; Martins, PauloThis paper presents a novel manufacturing process for producing innovative bi-material collector coins with free- rotating inner elements. The inner elements are fabricated using additive manufacturing, enabling the creation of coins with complex and intricate geometric details that would be unattainable using conventional wrought materials. The outer elements (rings) are metallic, and this study addresses the ...
A strain acceleration method to identify the onset of diffuse necking
Sampaio, Rui F. V.; Pragana, João; Bragança, Ivo; Silva, Carlos; Martins, PauloThis paper presents an innovative ‘strain acceleration method’ for determining the onset of diffuse necking in sheet forming tests using data obtained from digital image correlation (DIC). The method identifies the onset time of diffuse necking and provides the corresponding in-plane principal strain values by detecting a local extreme in the second derivative of the minor principal in-plane strain with respect...
Exploring wire-arc additive manufactured rivets for joining hybrid electrical b...
Rosado, Pedro M. S.; Sampaio, Rui F. V.; Pragana, João P. M.; Bragança, Ivo; Silva, Carlos M. A.; Martins, Paulo A. F.This paper presents a joining by plastic deformation process for fabricating hybrid electrical busbars made from copper and aluminum sheets. The process comprises the innovative use of wire-arc additive manufacturing to deposit copper rivets at specific locations on the copper sheets, the machining of slots with the required geometry in the aluminum sheets, and the compression of the copper sheets to force the ...
A statistical assessment of drilling effects on glass fiber-reinforced polymeri...
Martins, Ana; Carvalho, Alda; Bragança, Ivo; Barbosa, Inês; Barbosa, Joaquim; Loja, AméliaFiber-reinforced composites are extensively used in many components and structures in various industry sectors, and the need to connect and assemble such types of components may require drilling operations. Although drilling is a common machining process; when dealing with fiber-reinforced composite materials, additional and specific problems may arise that can com-promise mechanical integrity. So, the main goa...
Mechanical and thermal processing of wire-arc additively deposited stainless steel
Silva, Carlos; Pragana, João; Bragança, Ivo; Martins, PauloMechanical and thermal processing of wire-arc additively deposited stainless steel is investigated with the purpose of improving its microstructure, surface morphology, formability, and stress response. Microscopy helps identifying the processing conditions that permit full recrystallization of the as-built columnar microstructure. Combination with strain loading paths, topography and fractography in tensile te...
A software for research and education in ductile damage
Sampaio, Rui F.V.; Alexandre, N. S. M.; Pragana, João P. M.; Bragança, Ivo; Silva, Carlos; Martins, PauloThis paper gives insight into the development and utilization of a computer software that uses raw experimental data from the load cells and DIC systems to obtain the instant of time at fracture tf, the loading paths in principal strain space & epsilon;1 = f(& epsilon;2), and their conversion into the space of effective strain vs. stress triaxiality & epsilon; = f (& eta;). Special emphasis is given to the diff...
Joining of hybrid busbars for e-mobility: an economic and environmental study
Pragana, João P. M.; Sapage, Miguel S. T.; Sampaio, Rui F.V.; Bragança, Ivo; Ribeiro, Inês; Silva, Carlos M. A.; Martins, PauloThis paper presents a model to evaluate and analyze the costs of joining hybrid (copper-aluminum) busbars when different production processes are deployed. The process-based cost model (PBCM) is built upon the subdivision of the production cycle in three different stages related with the fabrication or purchase of auxiliary joining elements, preparation of the individual copper and aluminum conductors, and fina...