Descrizione del progetto
Una nuova tecnica ibrida di saldatura migliora le proprietà meccaniche e chimiche delle giunzioni
La giunzione di grandi sottocomponenti aeronautici può essere impegnativa sia per quanto concerne il processo stesso, sia per l’impatto a lungo termine esercitato sull’integrità del velivolo. La saldatura a punti per attrito e mescolamento con riempimento è una promettente tecnica di saldatura a stato solido che si avvale dell’attrito per pre-riscaldare e ammorbidire un componente, successivamente plasmato in modo da formare una giunzione. Il processo può ridurre il peso eliminando gli elementi di fissaggio, come ad esempio i rivetti, e saldare tra loro materiali dissimili. Il progetto DAHLIAS, finanziato dall’UE, sta ottimizzando questa tecnica promettente combinandola con l’applicazione di un sigillante dotato di proprietà adesive. Non solo questo sigillante è in grado di proteggere la giuntura dalla corrosione, ma ne rafforza per di più le prestazioni meccaniche.
Obiettivo
The main objective of the DAHLIAS project is to optimise hybrid joining (Refill Friction Stir Spot Welding, RFSSW, with an adhesive sealant bond) for application in aircraft structures. RFSSW is a solid-state joining technology especially applicable to lightweight alloys in similar and dissimilar configurations. The process has been successfully applied to difficult-to-weld and non-weldable alloys and is considered a potential replacement of mechanical fastening. Overlap joints in aircraft structures require the use of sealants for corrosion protection reasons. Using sealants with an adhesive function would complement the high quality joints produced by RFSSW by not only protecting against corrosion but also contributing to the overall mechanical performance of the structure. To achieve the main goal of this project a work plan consisting of eight work packages has been devised. Two work packages are focused on the RFSSW process development using standard samples with and without adhesive sealant. In parallel the adhesive sealant technology, including surface pre-treatment will be developed. The hybrid joining solution developed in this project will be compared to conventional joining technologies to define its potential. Hybrid joining brings a number of advantages to production and performance of aircraft structures. The change from differential to integral design introduces new challenges in the analysis of mechanical performance. Hence, the damage tolerance behaviour of hybrid joints is also investigated in this project. Quality control methods will be investigated by selecting NDT methods and by process control based on online monitoring of parameters. In the last phase of this project technology demonstrators will be produced to evaluate the capabilities of the proposed technology in actual aircraft structures. The consortium (3 R&D and 2 industrial partners) has the exact fitting, prooven expertise and high excellence. HZG (coordinator) holds key patents.
Campo scientifico
Programma(i)
Meccanismo di finanziamento
CS2-IA - Innovation actionCoordinatore
21502 Geesthacht
Germania