PSI - Issue 7

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com ScienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 7 (2017) 222–228 Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2017) 000–000 Available online at www.sciencedirect.com

www.elsevier.com / locate / procedia

www.elsevier.com/locate/procedia www.elsevier.com / locate / procedia

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. ∗ Corresponding author. Tel.: + 7-495-433-6257 ; fax: + 7-499-739-9531. E-mail address: perelm@ipmnet.ru 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. The approach to crack analysis based on the consideration of thermofluctuational kinetics of bonds in the crack cohesive zone was initially proposed in (Barenblatt et al., 1966, 1967), where it was assumed that this zone is small compared to the crack length. The crack tip propagation is determined by the material adhesion modulus depending ∗ Corresponding author. Tel.: + 7-495-433-6257 ; fax: + 7-499-739-9531. E-mail address: perelm@ipmnet.ru 2210-7843 c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. XV Portuguese Conference on Fracture, PCF 2016, 10-12 February 2016, Paço de Arcos, Portugal Thermo-mechanical modeling of a high pressure turbine blade of an airplane gas turbine engine P. Brandão a , V. Infante b , A.M. Deus c * a Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal b IDMEC, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal c CeFEMA, Department of Mechanical Engineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal Abstract 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 company, 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. Copyright © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Kinetics of cracks nucleation on materials interface Robert Goldstein, Mikhail Perelmuter ∗ A. Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Sciences, Prospect Vernadskogo 101-1, Moscow, 119526, Russia Abstract In this paper the model of cracks nucleation on materials interface is developed This model is based on the alliance of the bridged crack model and the thermofluctuational strength theory. The using of the bridged crack model allows to consider a zone of weakened bonds on a material interface as a bridged interface crack and the thermofluctuational theory determines the law of bonds rupture along this zone. The bond destruction in the crack bridged zone is modelled by the bonds compliance variation along the crack bridged zone and over time. Numerical calculations we e performed for the physical and mechanical parameters of the joint materials and bonds whi are used in microelectronics applications. The re ults of computation are presented and discussed. c 2017 The Authors. Published by Elsevier B.V. Peer-review under r sponsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material D fects. Keywords: the mofluctuational theo y; bonds kin tics; cra ks nucleation; crack ridged zone; 1. Introduction Models of a crack with interaction of its surfaces make possible to combine approaches of mechanics, physics and chemistry of fracture while analyzing the crack growth. Zones of crack surfaces interaction adjoin crack tips and they are commonly related to crack parts where cohesion forces are applied to the crack surfaces and suppress the crack opening. Di ff erent versions of such models (cohesive or bridged) for analyzing brittle, elastic-plastic and viscoelastic fracture w re proposed. The model of an interface crack under an external mechanical loading and with bonds in the bridged zone allows to determine the crack resistance and the adhesive strength of joints between di ff erent materials on the basis of micromechanical properties of bonds (Goldstein and Perelmuter, 1999, 2009). The extension of this model accounting thermally activated (thermofluctuational) bonds kinetics (Zhurkov, 1965) in the crack bridged zone is considered in this paper. The approach to crack analysis based on the consideration of thermofluctuational kinetics of bonds in the crack cohesive zone was initially proposed in (Barenblatt et al., 1966, 1967), where it was assumed that this zone is small compared to the crack length. The crack tip propagation is determined by the material adhesion modulus depending 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017, 19-22 September 2017, Lecco, Italy Kinetics of cracks nucleation on materials interface Robert Goldstein, Mikhail Perelmuter ∗ A. Ishlinsky Institute for Problems in Mechanics f the Russian Academy of Sc ences, Prospect Vernadskogo 101-1, Moscow, 119526, Russia Abstract In this paper the model of cracks nucleation on materials interface is developed. This model is based on the alliance of the bridged crack model and the thermofluctuational strength theory. The usin of the bridged crack model allows to consider a zone of weakened bonds on a material interface as a bridged interface cra k and the thermofluctuational theory determines the law f bonds rupture along this zone. The bond destruction in the crack bridged zone is modelled by the bonds compliance variation along the crack bridged zone and over time. Numerical calculations were performed for the physical and mechanical parameters of the joint materials and bonds which are used in microelectronics applications. The results of computation are presented and discussed. c 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material D fects. Keywords: thermofluctuational theory; bonds kinetics; cracks nucleation; crack bridged zone; 1. Introduction Models of a crack with interaction of its surfaces make possible to combine approaches of mechanics, physics and chemistry of fracture while analyzing the crack growth. Zones of crack surfaces interaction adjoin crack tips and they are commonly related to crack parts where cohesion forces are applied to the crack surfaces and suppress the crack opening. Di ff erent versions of such models (cohesive or bridged) for analyzing brittle, elastic-plastic and viscoelastic fracture were proposed. The odel of an interface crack under an external mechanical loading and with bonds in the bridged zone allows to determine the crack resistance and the adhesive strength of joints between di ff erent materials on the basis of micromechanical properties of bonds (Goldstein and Perelmuter, 1999, 2009). The extension of this model accounting thermally activated (thermofluctuational) bonds kinetics (Zhurkov, 1965) in the crack bridged zone is considered in this paper. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Keywords: High Pressure Turbine Blade; Creep; Finite Element Method; 3D Model; Simulation. * Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 Copyright  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of the 3rd International Symposium on Fatigue Design and Material Defects. 10.1016/j.prostr.2017.11.081