PSI - Issue 5

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com Sci ceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structu al Integrity 5 (2017) 31 –317 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2017) 000 – 000

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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. 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal Mitigation of weld residual deformations by weld sequence optimization: limitations and enhancements of surrogate models Etienne Bonnaud a, * a Inspecta Technology, Box 30100, 104 25 Stockholm, Sweden Abstract In this study, the use of a surrogate model to mitigate welding deformations in two simple but fundamental geometries, namely plates and pipes, respectively connected by a symmetrical 8 beads X-weld is investigated. Reasons why straight forward utilization of a surrogate model cannot give reliable results in these two cases are precisely pointed out and modifications are introduced to correct the problem. The enhanced algorithm is then shown to accurately predict displacements and to find the bead sequence giving the smallest possible displacement. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. Keywords: weld residual deformations; weld sequence optimization; surrogate models 1. Introduction Among all possible joining methods, fusion welding is still by far the most widely used. During the process, material in and around the weld experiences expansion at heating and contraction at cooling which generates unwanted residual stresses and residual deformations. A variety of techniques have been developed over the years to minimize stresses and deformations but for welds consisting of several passes, bead sequence is one of the most important parameters as it strongly affects the final stress and deformation states, see Mochizuki et al. (2000) and Sattari-Far et al. (2008). In order to avoid costly and time consuming trial and error welding experiments, numerical simulations based on the Finite Element M thod are extensively used to predict residual stresses and deformations. Usually a thermal analysis is first carried out to capture the time dependent temperature distribution in the welded structure and these results subsequently serves as an input for a m chanical analysis. Depending of the size of th mod l and t e number of beads, he total simulation time can vary from one to several hours for a two dimensional analysis and from one to several days for a three dimensional analysis. To be reliable, optimization techniques must cover the full range of possible combinations. Unfortunately the number of combinations grows very fast with the number of alternatives. A simple symmetrical eight beads X-weld (see Fig. 1) connecting two pipes together can for example be welded in 560 different ways (symmetry being taken into account). 2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal itigation of weld residual defor ations by weld sequence optimization: li itations and enhance ents of surrogate odels Etienne Bonnaud a, * a Inspecta Technology, Box 30100, 104 25 Stockholm, Sweden Abstract In this study, the use of a surrogate model to mitigate welding deformations in two simple but fundamental geometries, namely plates and pipes, resp c ively on ected by a symmetrical 8 beads X-weld is in e tigat . Reasons why straight forward utilization of a surrogate model cannot give reliable results in these two cases are precisely pointed out and modifications are introduced to correct the problem. The enhanced algorithm is then shown to accurately predict displacements and to find the bead sequence giving the smallest possible displacement. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. Keywords: weld residual deformations; weld sequence optimization; surrogate models 1. Introduction Among all possible joining methods, fusion welding is still by far the most widely used. During the process, material in and around the weld experiences expansion at heating and contraction at cooling which generates unwanted residual stresses and residual deformations. A variety of techniques have been developed over the years to minimize stresses and deformations but for welds consisting of several passes, bead sequence is one of the most important parameters as it strongly affects the final stress and deformation states, see Mochizuki et al. (2000) and Sattari-Far et al. (2008). In order to avoid costly and time consuming trial and error welding experiments, numerical simulations based on the Finite Element Method are extensively used to predict residual stresses and deformations. Usually a thermal analysis is first carried out to capture the time dependent temperature distribution in the welded structure and these results subsequently serves as an input for a mechanical analysis. Depending of the size of the model and the number of beads, the total simulation time can vary from one to several hours for a two dimensional analysis and from one to several days for a three dimensional analysis. To be reliable, optimization techniques must cover the full range of possible combinations. Unfortunately the number of combinations grows very fast with the number of alternatives. A simple symmetrical eight beads X-weld (see Fig. 1) connecting two pipes together can for example be welded in 560 different ways (symmetry being taken into account). © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017 © 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 * Corresponding author. E-mail address: Etienne.Bonnaud@inspecta.com * Corresponding author. E-mail address: Etienne.Bonnaud@inspecta.com

2452-3216 © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of PCF 2016. 2452-3216  2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017 10.1016/j.prostr.2017.07.176 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ICSI 2017. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-revi w under responsibility of the Scientifi Committee of ICSI 2017.