PSI - Issue 2_B

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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.2016.06.301 Cable ageing studies are often focusing on the cable insulation, since the loss of insulation might lead to the loss of cable functionalities. Cable insulation is typically made of polymers like polyethylene (PE), polyvinyl chloride (PVC), ethylene-propylene elastomers (EPR, EPDM), or cross-linked polyethylene (XLPE). Some cables which are used in ∗ Corresponding author email: tamara.djikanovic@sckcen.be 2452-3216 c ⃝ 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. 1. Intorudction Th lifetime extension of existing nuclear power plants (NPP) relie on valid tion of he safe long term perfor mance. For that purpose it is of outmost importance to demonstrate the structural and functional integrity of the NPP constituents for extended time usage. Unlike som other components, the monitoring program for cables has not been established, so NPP industry expressed the need for accelerated cable ageing experiments, additional testing and analysis of cable prop rties. Cable ageing studies ar often focusing on the cable insulation, ince the loss of insulation might lead to the loss of cable functionalities. Cable ns lation is typically made of polymers like polyethylene (PE), polyvinyl chlorid (PVC), ethylene-propylene elastomers (EPR, EPDM), or cross-linked polyethylene (XLPE). Some cables which are used in ∗ Corresponding author email: tamara.djikanovic@sckcen.be 2452-3216 c ⃝ 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Abstra t The echanical properties of industrial and neat Ethylene Propylene iene ono er (EP ) poly ers, aged under γ -irradiation at di ff erent te peratures, are studied. The focus is given to the dose rate e ff ects in poly er insulation aterials, so the ageing is perfor ed in the ide range of dose rates, doses and te peratures. Industrial EP sa ples are extracted fro the cables in use in elgian uclear Po er Plants ( PP), and the neat EP sa ples are produced in the laboratory. The echanical tests of non-aged and aged poly ers are perfor ed, and the ethodology of esti ating the poly er life ti e is discussed. The ultimate tensile stress and elongation at break are found to be strongly a ff ected by both irradiation condition and te perature. The ulti ate tensile stress clearly exhibits the dose rate e ff ect observed through the shift of the crossover bet een cross-linking to chain scission process as a function of the dose. This crossover shifts to high dose for large dose rates, hile the opposite is observed by increasing the te perature. ose rate e ff ect is less evident in the elongation at break data, probably because both cross-linking and chain scission a ff ect the elongation at break in the sa e ay, by decreasing it. In co parison to industrial EP aged under the sa e conditions, the cross-linking to chain scission crossover appears at lo er dose in neat poly er and the elongation at break decreases faster by increasing the dose. In addition, the elongation at break experi ental results can be odeled by changing single para eter, namely pre-exponential factor of the irradiation rate constant. This confir s that both aging processes, cross-linking and chain scission a ff ect the elongation at break in a si ilar ay, by deteriorating net ork structure responsible for poly er elastic properties. Irradiation rate constant is found to follo the square root dependence for industrial EPDM, while the linear dependence is observed for the neat EP . This indicates the existence of di ff erent degradation processes in these t o poly ers. c ⃝ 2016 The uthors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of E F21. ey ords: poly er degradation; echanical properties; radiation and ther al ageing; EP 1. Intorudction he lifeti e extension of existing nuclear po er plants ( PP) relies on validation of the safe long ter perfor ance. For that purpose it is of out ost i portance to de onstrate the structural and functional integrity of the PP constituents for extended ti e usage. nlike so e other co ponents, the onitoring progra for cables has not been established, so PP industry expressed the need for accelerated cable ageing experi ents, additional testing and analysis of cable properties. able agei studies are often focusing on the cable insulation, since the loss of insulation ight lead to the loss of cable functionalities. able insulation is typically ade of poly ers like polyethylene (P ), polyvinyl chloride (P ), ethylene-propylene elastomers (EPR, EPDM), or cross-linked polyethylene ( P ). So e cables hich are used in ∗ Corresponding author e ail: ta ara.djikanovic sckcen.be 2452-3216 c ⃝ 2016 The Auth rs. Published by Elsevier B.V. Peer-review under resp nsibility of the Scientific Committee of ECF21. 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/). e -review under responsibility of the Scientific Committee of ECF21. 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 The study of temperature and radiation induced degradation of cable polymers: A comparison between the mechanical properties of industrial and neat EPDM T. Sˇ arac a , N. Quie´vy b , A. Gusarov a , M. J. Konstantinovic´ a a SCK · CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol, Belgium b Laborelec, Rodestraat 125, B-1630 Linkebeek, Belgium Abstract The mechanical properties of industrial and neat Ethylene Propylene Diene Monomer (EPDM) polymers, aged under γ -irradiation at di ff erent temperatures, are studied. The focus is given to the dose rate e ff ects in polymer insulation materials, so the ageing is performed in the wide range of dose rates, doses and temperatures. Industrial EPDM samples are extracted from the cables in use in Belgian Nuclear Power Plants (NPP), and the neat EPDM samples are produced in the laboratory. The mechanical tests of non-aged and aged polymers are performed, and the methodology of estimating the polymer life time is discussed. The ultimate tensile stress and elongation at break are found to be strongly a ff ected by both irradiation condition and temperature. The ultimate tensile stress clearly exhibits the dose rate e ff ect observed through the shift of the crossover between cross-linking to chain scission process as a function of the dose. This crossover shifts to high dose for large dose rates, while the opposite is observed by increasing the temperature. Dose rate e ff ect is less evident in the elongation at break data, probably because both cross-linking and chain scission a ff ect the elongation at break in the same way, by decreasing it. In comparison to industrial EPDM aged under the same conditions, the cross-linking to chain scission cross ver appears at lower dose in neat polymer and the elongation t break de reases faster by increasing the dos . In addition, t e elongation at break experimental results can be modeled by changing single parameter, namely pre-exponential factor of the irradi tion rate co stant. This confir s that both aging processes, cross-linking and chain scission a ff ec the elongation at bre k in a similar way, by deteriorating network structure responsible for polymer elastic properties. Irradiation r te co stant is found to follow the squar root ep dence for industrial EPDM, while the lin ar dependence is observed for the neat EPDM. This indicates th exis ence of di ff erent degradation processes in thes two polym rs. c ⃝ 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: polymer degradation; mechanical properties; radiation and thermal ageing; EPDM 1. Intorudction The lifetime extension of existing nuclear power plants (NPP) relies on validation of the safe long term perfor mance. For that purpose it is of outmost importance to demonstrate the structural and functional integrity of the NPP constituents for extended time usage. Unlike some other components, the monitoring program for cables has not been established, so NPP industry expressed the need for accelerated cable ageing experiments, additional testing and analysis of cable properties. 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy The study of temperature and radiation induced degradation of cable polymers: A comparison between the mechanical properties of industrial and neat EPDM T. Sˇ arac a , . Quie´vy b , A. Gusarov a , M. J. Konstantinovic´ a a SCK · CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol, Belgium b Laborelec, Rodestraat 125, B-1630 Linkebeek, Belgium Abstract The mechanical properties of industrial and neat Ethylene Propylene Diene Monomer (EPDM) polymers, aged under γ -irradiation at di ff erent temperatures, are studied. The focus is given to the dose rate e ff ects in polymer insulation materials, so the ageing is performed in the wide range of dose rates, doses and temperatures. Industrial EPDM samples are extracted from the cables in use in Belgian Nuclear Power Plants (NPP), and the neat EPDM samples are produced in the laboratory. The mechanical tests of non-aged and aged polymers are performed, and the methodology of estimating the polymer life time is discussed. The lti ate te sile stress and elongation at break are found t be strongly a ff ected by both irradiation conditio and temperature. The ultimate tensile stress clearly exhibits the dose rate e ff ect observed th ough the shift f the crossover between cr ss-linking to chain scission process as a function of the dose. This cros over shifts to high dose for large dose rates, while the opposite is observ d by increasing the temperature. Do e ate e ff ect is less evident in the elonga io at break data, pr bably because both cross-linking and chain scission a ff ect the elongation at break n the same way, by decreasing it. In comparison to industrial EPDM aged under the same conditions, the cross-linking to chain scission crossover appears at lower dose in neat polymer an the elongation at break decreas s faster b increasing the dose. In addition, the elongation at break experimental results can be modeled by changing single parameter, namely pre-exponenti l factor of the irradiation rate constant. This confirms that both aging processes, cross-linking and chain scission a ff ect t e elongation at reak in a similar way, by deteriorating network structure responsible for polymer elastic pr perties. Irradiation rate constant is found to follow the square root dependence for industrial EPDM, while the linear dependence is observed for the neat EPDM. This indicates the existence of di ff erent degradation processes in these two polymers. c ⃝ 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of ECF21. Keywords: polymer degradation; mechanical properties; radiation and thermal ageing; EPDM st r ea fere ce ract re, , - J e , ata ia, Ital t f t r t r r i ti i r ti f l l r : ri t t i l r rti f i tri l d t T. ˇ r a , . i´ b , . s r v a , . J. st ti i´ a a SCK · CEN, Nuclear aterials Science Institute, Boeretang 200, B-2400 ol, Belgiu b Laborelec, Rodestraat 125, B-1630 Linkebeek, Belgium © 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