Residual Stress Analysis of Laser-Drilled Thermal Barrier Coatings Involving Various Bond Coats
TypeArticles dans des revues avec comité de lecture
The gas turbine combustion chamber of aero-engines requires a thermal barrier coating (TBC) by thermal spraying. Further heat protection is achieved by laser drilling of cooling holes. The residual stresses play an important role in the mechanical behaviour of TBC. It could also affect the TBC response to delamination during laser drilling. In this work, studies of the cracking behaviour after laser drilling and residual stress distribution have been achieved for different bond coats by plasma spray or cold spray. From interface crack length measured pulse-by-pulse after laser percussion drilling at 20° angle, the role of the various bond coats on crack initiation and propagation are investigated. It is shown that the bond coat drastically influences the cracking behaviour. The residual stresses profiles were also determined by the incremental hole-drilling method involving speckle interferometry. An original method was also developed to measure the residual stress profiles around a pre-drilled zone with a laser beam at 90°. The results are discussed to highlight the influence of TBCs interfaces on the resulting residual stresses distribution before laser drilling, and also to investigate the modification around the hole after laser drilling. It is shown that laser drilling could affect the residual stress state.
Showing items related by title, author, creator and subject.
GIRARDOT, Jérémie; ILLOUL, Lounès; LORONG, Philippe; RANC, Nicolas; SCHNEIDER, Matthieu; BERTHE, Laurent; FAVIER, Véronique (2012)These works present a numerical alternative to the simulation of the laser drilling process. The use of the finite element method to modeling the hole creation during a laser pulse shows difficulties in front of a moving ...
Procédé de perçage par laser : Comparaison entre des données expérimentales et une simulation 2D basée sur la méthode CNEM GIRARDOT, Jérémie; RANC, Nicolas; SCHNEIDER, Matthieu; LORONG, Philippe; ILLOUL, Lounès; BERTHE, Laurent; FAVIER, Véronique (Congrès français de mécanique (21 ; 2013 ; Bordeaux (Gironde), 2013)This work presents a numerical alternative for the laser drilling simulation problem. Using finite element method is difficult to simulate the hole propagation over time, especially because of moving boundaries due to a ...
GIRARDOT, Jérémie; ILLOUL, Lounès; LORONG, Philippe; RANC, Nicolas; SCHNEIDER, Matthieu; BERTHE, Laurent; FAVIER, Véronique (2012)Ces travaux présentent une alternative numérique au problème de simulation du procédé de perçage par laser. L’utilisation des éléments finis pour modéliser la propagation du trou au cours du temps montre des limites ...
GIRARDOT, Jérémie; LORONG, Philippe; ILLOUL, Lounès; RANC, Nicolas; SCHNEIDER, Matthieu; FAVIER, Véronique (Springer, 2015)The laser drilling process is the main process used in machining procedures on aeronautic engines, espe- cially in the cooling parts. The industrial problematic is to reduce geometrical deviations of the holes and defects ...
GIRARDOT, Jérémie; SCHNEIDER, Matthieu; BERTHE, Laurent; FAVIER, Véronique (Elsevier, 2013)Temperatures in the high pressure chamber of aircraft engines are continuously increasing to improve the engine efﬁciency. As a result, constitutive materials such as cobalt and nickel-base superalloys need to be thermally ...