PSI - Issue 2_B

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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. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Micromechani al model for describing inte granular fatigue cracking in a lead-free solder alloy V. N. Le a,* , L. Benabou a , V. Etgens a , Q. B. Tao a a LISV, University of Versailles Saint Quentin-en-Yvelines, 45 avenue des Etats-Unis, 78035 Versailles, France Abstract Solder joints possess a small thickness of the order of a few grains but they remain one of the key concerns in thermo-mechanical reliability of high-power electronic systems. Fatigue lifetime of solder joints subjected to thermal and mechanical loading cycles is generally predicted based on phenomenological and macroscopic fatigue models that use the effective material properties as inputs. Such semi-empirical models will thus only provide a gross estimation of the engineering lifetime for some specific boundary and loading conditions while ignoring the deformation mechanisms at micro-scale. Microscopic analysis of fractured solder joints points rather to crack propagation at grain boundaries. Therefore, a 3D microstructure-informed model is developed in this study for reproducing the intergranular fatigue crack in the s lder joi t of a power mo ule. The submodeling tech ique has been applied in order to only investigate the critical zone of the solder joint. A global model of the whole module is first simulated to obtain the inputs for a submodel focused on the zone of interest where failure is expected to develop. The submodel simultaneously makes use of the cohesive zone and the crystal plasticity theories to represent decohesion at grain boundaries and plastic slips in the grains of the solder joint, respectively. The needed crystal plasticity parameters were fitted out with the help of the Berveiller-Zaoui homogenization scheme using experimental data, while the parameters for the cohesive zone model were estimated from some physical quantities. Simulations of repeated thermo-mechanical loading on the power module demonstrate how cracking occurs at grain boundaries in the solder joint of the submodel. In addition, it is shown that the crack propagation rate is almost constant during the whole loading time. This suggests an ability of the present approach to give a fatigue lifetime estimate for the entire solder joint by extrapolating some specific computed quantities from the local model. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy Micromechanical model for describing intergranular fatigue cracking in a lead-free solder alloy V. N. Le a,* , L. Benabou a , V. Etgens a , Q. B. Tao a a LISV, University of Versailles Saint Quentin-en-Yvelines, 45 avenue des Etats-Unis, 78035 Versailles, France Abstract Solder joints possess a small thickness of the order of a few grains but they remain one of the key concerns in thermo-mechanical reliability of high-power elec ronic systems. Fatigue lifetime of solder joints subjected to rmal and mechanical l ading cycles is generally predicted based on phenomenological and macroscopic fatigue mod ls that us the effective materia properties a nputs. Such semi-empirical models will thus nly provide gr s estim on of the ngineering lifetim for so e specific boundary a d loading conditions whi e ignoring the def rmati n mechani m at m cro-scal . Microscopic analysis of fractur d solder joints points rather to crack propagation at rain bound r es. Therefore, a 3D microstructure-informed model is develop in this study f r rep oducing the inte gr nular fatigue crack in the older joint of a power mod le. The sub odeling technique has been applied in o de to only inv stigate the critical zone of the solder joint. A global model of he whole module is first simulated to obtain he puts for a submodel focused on th zo f interest where failure is exp cted to devel p. The submodel si ltaneously makes use of the cohesive zone and the crystal plasticity th ories to represent d cohesion at grain boundaries and plastic slips in the gr in of the solder jo nt, respectively. The needed crystal plas icity parameters were fitted out with the help of the Berveiller-Zaoui homogenization scheme using experim ntal data, while the parameters for the coh sive zone model were estimated from some physical qu ntities. Simulations of repeated thermo-mechanical loading on the power module de onstrate how cracking occurs at grain boundaries in the solder joint of th submodel. In ddition, it is shown that the crack propagation rate is almost constan during the whole loading time. This sugg sts an abi ity of the present approach to give fatigue life me estimate f r the entire solder joint by extrapolating some specific computed quantities from the local model. © 2016 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of ECF21. Keywords: Intergranular fatigue fracture; lead-free solder; crystal plasticity; cohesive zone; finite element modelling. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativ commons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientifi Committee of ECF21. © 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. Keywords: Intergranular fatigue fracture; lead-free solder; crystal plasticity; cohesive zone; finite element modelling.

* Corresponding author. Tel.: +33 1 39 25 49 34. E-mail address: vannhat.le@lisv.uvsq.fr * Corresponding author. Tel.: +33 1 39 25 49 34. E-mail address: vannhat.le@lisv.uvsq.fr

* Corresponding author. Tel.: +351 218419991. E-mail address: amd@tecnico.ulisboa.pt 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21.

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. Copyright © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Peer review under responsibility of the Scientific Committee of ECF21. 10.1016/j.prostr.2016.06.327