PSI - Issue 13

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ScienceDirect

ScienceDirect Available online at www.sciencedirect.com Av ilable o line at ww.sciencedire t.com cienceDirect Structural Integrity Procedia 00 (2016) 000 – 000 Procedia Structural Integrity 13 (2018) 1915–1923 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2018) 000–000 Structural Integrity Procedia 00 (2018) 000–000

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia ECF22 - Loading and Environmental effects on Structural Integrity Effects of manufacturing plastic prestrains found on calendered and UOE pipes and pressure vessels on structural integrity assessments reg rding fatigue crack growth a LBB Rodrygo Figueiredo Moço a , Fábio Gonçalves Cavalcante a , Gustavo Henrique Bolognesi Donato a * a Centro Universitário FEI, Humberto de A. Castelo Branco Av., 3972, São Bernardo do Campo, 09850-901, Brazil Abstract High responsibility components operating under cyclic loading can have their r sistance against initiation and growth of fatigue cracks highly influenced by previous thermomechanical processing. Within the interest of the present work, different manufacturing processes (such s the fabrication of pipes using UOE) or installation procedures (such a pipe reeling) can lead to nonuniform plastic prestrain fields thus affecting lifetime and safety. Previous studies conducted by the authors revealed that prestraining up to 14% considerably reduced fatigue cr ck growth rates ( da/ N- Δ K ) for a hot-rolled (1/2”) ASTM-A36 steel as a result of strain hardenin and its effects on plastic zone sizes. In addition, r sults also reveal d two interesting trends: i) the larger is the imposed restrain, the greater is the growth rate red ction in a n nli e r symptotic relationship; ii) the larger is imposed Δ K , the more ronounc d is the effect of prestraining. Within this scenari , this work explor s the effects of those results on more realistic lifetime predictions applicable to pipelines and pressure vessels. First, n nlinear model based on the experimental results was developed to predict crack growth rates ( da/dN ) as a function of Δ K and varying plastic prestrain levels. Second, refined nonlinear FE models were developed to quantify plastic prestrain fields caused by manuf cturing sequence of the studied pressure vessels and pipes. Such fields proved to be remarkably nonuniform, in accordance to the literatur . Finally, consid ring an idealized cycli internal r ssure and the obtained fields, a MatLab algorithm was implemented to predict fatigue crack growth rates until LBB (Leak Before Break) conditi n takes place. Best practices for implementing such evaluations are presented and results revealed that effects of plastic prestrains re not negligible and should be taken into ac ount on recommended practices and structural integrity assessments to a oid excessive conservatism or lack of safety in applications. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 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. ECF22 - Loading and Environmental effects on Structural Integrity Effects of manufacturing plastic prestrains found on calendered and UOE pipes and pressure vessels on structural integrity assessments regarding fatigue crack growth and LBB Rodrygo Figue redo Moço a , Fábio Gonçalves Cavalcante a , Gustavo Henrique Bolognesi Donato a * a Centro Universitário FEI, Humberto de A. Castelo Branco Av., 3972, São Bernardo do Campo, 09850-901, Brazil Abstract High responsibility components operating under cyclic loading can have their esistance against initiation and growth of fatigue cracks highly influenced by previous thermomechanical processing. Within the interest of the present work, different manufacturing processes (such as the fabrication of pipes using UOE) or installation procedures (such as pipe reeling) can lead to nonuniform plastic prestrain fields thus affecting lifetime and safety. Previous studies conducted by the authors revealed that prestraining up to 14% considerably reduced fatigue crack growth rates ( da/dN- Δ K ) for a hot-rolled (1/2”) ASTM-A36 steel as a result of strain hardening and its effects on plastic zone sizes. In addition, results also revealed two interesting trends: i) the larger is the imposed prestrain, the greater is the growth rate reduction in a nonlinear asymptoti relationship; ii) the larger is imposed Δ K , the more pronounced is the effect of prestraining. Within this scenario, this work explores the effects of those results on more realistic lifetime predictions applicable to pipelines and pressure vessels. First, a nonlinear model based on the experimental results was developed to predict crack growth rates ( da/dN ) as a function of Δ K and varying plastic prestrain levels. Second, refined nonlinear FE models were dev loped to quantify plastic pr str in fields caused by manufacturing sequence of the studied pressure vessels and pipes. Such fields proved to be remarkably nonuniform, in accordance to the literature. Finally, consi ering an idealized cyclic internal pressure and the obtained fields, a MatLab algorithm was implemented to predict fatigue crack growth rates until LBB (Leak Before Break) condition takes place. Best practices for implementing such evaluations are presented and results revealed that ffects of plastic prestrai s are n t negligible and should be taken into account on recommended practices and structural integrity assessments to avoid excessive conservatism or lack of safety in applications. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. © 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.: +55-11-43532900. E-mail address: gdonato@fei.edu.br

2452-3216  2018 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ECF22 organizers. 10.1016/j.prostr.2018.12.270

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