Simulating the damage accumulation in aircraft bleed system ducts joined by laser and arc welding processes
✍ Scribed by S.M. Carvalho; C.A.R.P. Baptista; M.S.F. Lima
- Publisher
- Elsevier
- Year
- 2011
- Tongue
- English
- Weight
- 489 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1877-7058
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✦ Synopsis
The engine bleed system transports the hot air from the motor to the aircraft systems. Among the various materials suited for use in this system, pure titanium stands out because of its favorable characteristics. The pneumatic system components are subject to cyclic stresses leading to possible failures. The occurrence of fatigue failures in arc welded ducts lead us to develop and test an alternative welding process using a fibre laser of 2 kW in order to join titanium components for the aircraft bleed system. The lower thermal input of this process results in reduced dimensions of the weld beads and lower residual stresses and distortions when compared to the conventional arc welding. During the welding development stage, the best results were obtained at 200 W for a welding speed of 2 m/min. In order to assess the performance of welded joints, cyclic pressurization tests at the working temperature of 350°C and maximum pressure of 150 psi were conducted in the pneumatic workbench aimed at simulating the aging process suffered by the pneumatic system ducts. The microstructure and mechanical properties of the specimens were determined and the performances of laser beam and arc welded joints were compared.