Percorrer por autor "Rosado, Pedro M. S."
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- Enhancing the performance of double-flush riveted joints through hybridization with adhesive bondingPublication . 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 adhesive-bonded joints. A similar strategy is applied to construct double-flush riveted joints, focusing on the geometric variables involved in the process. Hybrid joints are then created by integrating adhesive bonding with double-flush riveting, with the second carried out before or after curing is completed. The experimental development is supported by finite element analysis conducted with an in-house computer program. The mechanical performance of the hybrid joints is compared to that of purely adhesive-bonded and conventionally double-flush riveted joints through shear and peel destructive testing. Results demonstrate that hybrid joints ultimately provide greater joint strength for both solicitations. This allows showcasing the hybridization of double-flush riveting with adhesive bonding as an effective solution for applications where joint strength and continuity are essential.
- Exploring wire-arc additive manufactured rivets for joining hybrid electrical busbarsPublication . 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 rivets into the pre-machined slots of the aluminum sheets, creating form-closed mechanical interlocks. The work combines experimentation and finite element modeling to analyze the influence of the most significant process parameters, and the electrical performance of the hybrid busbar joints is evaluated and compared to that of conventional fastened joints at different service temperatures. Results demonstrate the effectiveness and potential advantages of the new joining by plastic deformation process for fabricating hybrid electrical busbars.
- Joining by forming of bi-material collector coins with rotating elementsPublication . 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 challenge of securely connecting them to the inner elements through force-closed mechanisms formed during the coin minting process. Finite element modeling, combined with experimentation on bi-material (polymer-metal and metal-metal) coins, is employed to analyze material flow, assess minting forces, and evaluate contact pressures at the force-closed joints. The analysis ensures that adequate destructive forces are required to separate the inner elements from the rings and provides insights into selecting the appropriate process parameters for simultaneous coining and joining. The successful production of the first bi-material collector coin prototypes with free-rotational inner elements validates the overall development.