During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation

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... mpany, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data. Abstract The authors measured the local fracture stress of brittle crack propagation in steel plates. Many studies on brittle crack propagation in steel plates have been implemented based on energy balance, but they have not been able to provide full theoretical explanation to brittle crack propagation and arrest behavior in steel plates. On the other hand, although the local fracture stress concept has been emerging as a factor governing the behavior recently, the local fracture stress has not been evaluated sufficiently because the crack front shape and forming of shear lip have prevent us from implementing accurate FEM analysis of brittle crack propagation. So, we implemented brittle crack propagation tests using specimen with side groove which is designed to increase stress near the plate surface and make the crack front straight. Inputting crack velocities obtained from experiments, FEM analyses were implemented. Our analyses showed the local fracture stress is higher in low temperature than in high temperature. This trend can be explained from the aspect of forming of tear ridge, which is main mechanism to absorb energy during brittle crack propagation in steel plates. Abstract The authors measured the local fracture stress of brittle crack propagation in steel plates. Many studies on brittle crack propagation in steel plates have been implemented based on energy balance, but they have not been able to provide full theoretical explanation to brittle crack propagation and arrest behavior in steel plates. On the other hand, although the local fracture stress concept has been emerging as a factor governing the behavior recently, the local fracture stress has not been evaluated sufficiently because the crack front shape and forming of shear lip have prevent us from implementing accurate FEM analysis of brittle crack propagation. So, we implemented brittle crack propagation tests using specimen with side groove which is designed to increase stress near the plate surface and make the crack front straight. Inputting crack velocities obtained from experiments, FEM analyses were implemented. Our analyses showed the local fracture stress is higher in low temperature than in high temperature. This trend can be explained from the aspect of forming of tear ridge, which is main mechanism to absorb energy during brittle crack propagation in steel plates.