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Eriksson, Robert
Alternative names
Publications (10 of 38) Show all publications
Azeez, A., Eriksson, R., Leidermark, D. & Calmunger, M. (2020). Low cycle fatigue life modelling using finite element strain range partitioning for a steam turbine rotor steel. Theoretical and applied fracture mechanics (Print), 107
Open this publication in new window or tab >>Low cycle fatigue life modelling using finite element strain range partitioning for a steam turbine rotor steel
2020 (English)In: Theoretical and applied fracture mechanics (Print), ISSN 0167-8442, E-ISSN 1872-7638, Vol. 107Article in journal (Refereed) Epub ahead of print
Abstract [en]

Materials made for modern steam power plants are required to withstand high temperatures and flexible operational schedule. Mainly to achieve high efficiency and longer components life. Nevertheless, materials under such conditions experience crack initiations and propagations. Thus, life prediction must be made using accurate fatigue models to allow flexible operation. In this study, fully reversed isothermal low cycle fatigue tests were performed on a turbine rotor steel called FB2. The tests were done under strain control with different total strain ranges and temperatures (20 °C to 625 °C). Some tests included dwell time to calibrate the short-time creep behaviour of the material. Different fatigue life models were evaluated based on total life approach. The stress-based fatigue life model was found unusable at 600 °C, while the strain-based models in terms of total strain or inelastic strain amplitudes displayed inconsistent behaviour at 500 °C. To construct better life prediction, the inelastic strain amplitudes were separated into plastic and creep components by modelling the deformation behaviour of the material, including creep. Based on strain range partitioning approach, the fatigue life depends on different damage mechanisms at different strain ranges at 500 °C. This allows for the formulation of life curves based on either plasticity-dominated damage or creep-dominated damage. At 600 °C, creep dominated while at 500 °C creep only dominates for higher strain ranges. The deformation mechanisms at different temperatures and total strain ranges were characterised by scanning electron microscopy and by quantifying the amount of low angle grain boundaries. The quantification of low angle grain boundaries was done by electron backscatter diffraction. Microscopy revealed that specimens subjected to 600 °C showed signs of creep damage in the form of voids close to the fracture surface. In addition, the amount of low angle grain boundaries seems to decrease with the increase in temperature even though the inelastic strain amplitude was increased. The study indicates that a significant amount of the inelastic strain comes from creep strain as opposed of being all plastic strain, which need to be taken into consideration when constructing a life prediction model.

Keywords
Creep-fatigue interaction, Creep-resistant steel, EBSD, Low cycle fatigue, Steam turbine steel, Strain range partitioning
National Category
Applied Mechanics
Identifiers
urn:nbn:se:liu:diva-164610 (URN)10.1016/j.tafmec.2020.102510 (DOI)
Available from: 2020-03-26 Created: 2020-03-26 Last updated: 2020-03-26
Calmunger, M., Eriksson, R., Lindström, T. & Leidermark, D. (2019). Effect of Additive Manufacturing on Fatigue Crack Propagation of a Gas Turbine Superalloy. In: Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019.. Elsevier
Open this publication in new window or tab >>Effect of Additive Manufacturing on Fatigue Crack Propagation of a Gas Turbine Superalloy
2019 (English)In: Structural Integrity Procedia, Elsevier, 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Additive manufacturing, fatigue fractography, EBSD
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161724 (URN)
Conference
9th International Conference on Materials Structure and Micromechanics of Fracture, MSMF9, Brno, Czech Republic, June 26-28, 2019.
Available from: 2019-11-07 Created: 2019-11-07 Last updated: 2019-11-15Bibliographically approved
Jonnalagadda, K. P., Eriksson, R., Li, X.-H. & Peng, R. L. (2019). Fatigue life prediction of thermal barrier coatings using a simplified crack growth model. Journal of the European Ceramic Society, 39(5), 1869-1876
Open this publication in new window or tab >>Fatigue life prediction of thermal barrier coatings using a simplified crack growth model
2019 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 39, no 5, p. 1869-1876Article in journal (Refereed) Published
Abstract [en]

Models that can predict the life of thermal barrier coatings (TBCs) during thermal cycling fatigue (TCF) tests are highly desirable. The present work focuses on developing and validating a simplified model based on the relation between the energy release rate and the TCF cycles to failure. The model accounts for stresses due to thermal mismatch, influence of sintering, and the growth of TGO (alumina and other non-protective oxides). The experimental investigation of TBCs included; 1) TCF tests at maximum temperatures of 1050 °C, 1100 °C, 1150 °C and a minimum temperature of 100 °C with 1 h and 5 h (1100 °C) hold times. 2) Isothermal oxidation tests at 900, 1000 and 1100 °C for times up to 8000 h. The model was calibrated and validated with the experimental results. It has been shown that the model is able to predict the TCF life and effect of hold time with good accuracy.

Keywords
Thermal barrier coatings, Thermal cycling fatigue, Life prediction model, Energy release rate
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:liu:diva-154780 (URN)10.1016/j.jeurceramsoc.2018.12.046 (DOI)000459950700016 ()
Note

Funding agencies: Vinnova in Sweden

Available from: 2019-02-26 Created: 2019-02-26 Last updated: 2019-03-20
Wärner, H., Eriksson, R., Chai, G., Moverare, J., Johansson, S. & Calmunger, M. (2019). Influence of Ageing on Thermomechaical Fatigue of Austenitic Stainless Steels. In: Elsevier (Ed.), Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019. Elsevier
Open this publication in new window or tab >>Influence of Ageing on Thermomechaical Fatigue of Austenitic Stainless Steels
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2019 (English)In: Structural Integrity Procedia / [ed] Elsevier, Elsevier, 2019Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermomechanical fatigue, Austenitic stainless steels, Ageing, Barrelling effect
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161737 (URN)
Conference
9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-12
Azeez, A., Eriksson, R., Calmunger, M., Lindström, S. B. & Simonsson, K. (2019). Low Cycle Fatigue Modelling of Steam Turbine Rotor Steel. In: Elsevier (Ed.), Structural Integrity Procedia: . Paper presented at 9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019 (pp. 149-154). Elsevier, 23
Open this publication in new window or tab >>Low Cycle Fatigue Modelling of Steam Turbine Rotor Steel
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2019 (English)In: Structural Integrity Procedia / [ed] Elsevier, Elsevier, 2019, Vol. 23, p. 149-154Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Materials in steam turbine rotors are subjected to cyclic loads at high temperature, causing cracks to initiate and grow. To allow for more flexible operation, accurate fatigue models for life prediction must not be overly conservative. In this study, fully reversed low cycle fatigue tests were performed on a turbine rotor steel called FB2. The tests were done isothermally, within temperature range of room temperature to 600 °C, under strain control with 0.8-1.2 % total strain range. Some tests included hold time to calibrate the short-time creep behaviour of the material. Different fatigue life models were constructed. The life curve in terms of stress amplitude was found unusable at 600 °C, while the life curve in terms of total strain or inelastic strain amplitudes displayed inconsistent behaviour at 500 °C. To construct better life model, the inelastic strain amplitudes were separated into plastic and creep components by modelling the deformation behaviour of the material, including creep. Based on strain range partitioning approach, the fatigue life depends on different damage mechanisms at different strain ranges. This allowed the formulation of life curves based on plasticity or creep domination, which showed creep domination at 600 °C, while at 500 °C, creep only dominates for higher strain range.

Place, publisher, year, edition, pages
Elsevier, 2019
Series
Procedia Structural Integrity, ISSN 2452-3216
Keywords
Low cycle fatigue, Creep-fatigue intraction, Strain range partitioning, FB2, Creep-resistant steel, Rotor steel
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-161736 (URN)10.1016/j.prostr.2020.01.078 (DOI)
Conference
9th International Conference on Materials Structures and Micromechanics of Fracture, MSMF9, in Brno, Czech Republic, June 26-28, 2019
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2020-03-02Bibliographically approved
Jonnalagadda, K. P., Eriksson, R., Li, X.-H. & Peng, R. L. (2019). Thermal barrier coatings: Life model development and validation. Surface & Coatings Technology, 362, 293-301
Open this publication in new window or tab >>Thermal barrier coatings: Life model development and validation
2019 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 362, p. 293-301Article in journal (Refereed) Published
Abstract [en]

The failure of thermal barrier coatings (TBCs) during thermal cyclic fatigue (TCF) tests depends mainly on the thermal mismatch between the coating and the substrate, the thermally grown oxides (TGO) at the top coat-bond coat interface, and the sintering of the top coat. Understanding the interplay between these factors is essential for developing a life model. The present work focuses on further development of a previously established fracture mechanics based life model and its validation by comparing with the experimental results. The life model makes use of a Paris' law type equation to estimate the cycles to failure based on micro-crack growth. The fitting parameters for the Paris' law were obtained from the experimentally measured crack lengths after the interruption of TCF tests at different cycles. An alternative approach to obtain the fitting parameters through video monitoring was also discussed. It is shown that regardless of the approach to obtain the fitting parameters, the life model in its current form is able to predict the TCF life at different temperatures with reasonable accuracy. However, at very high temperatures (1150 °C) the predictive capabilities of the model appeared to be poor.

Keywords
Thermal barrier coatings, Thermal cyclic fatigue, Life modeling, Life prediction
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:liu:diva-154779 (URN)10.1016/j.surfcoat.2019.01.117 (DOI)000461526400035 ()
Note

Funding agencies: VINNOVA in Sweden

Available from: 2019-02-26 Created: 2019-02-26 Last updated: 2019-04-03
Eriksson, R., Chen, Z. & Jonnalagadda, K. P. (2017). Bending Fatigue of Thermal Barrier Coatings. Journal of engineering for gas turbines and power, 139(12), 122101-1-122101-6
Open this publication in new window or tab >>Bending Fatigue of Thermal Barrier Coatings
2017 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 139, no 12, p. 122101-1-122101-6Article in journal (Refereed) Published
Abstract [en]

Thermal barrier coatings (TBCs) are ceramic coatings used in gas turbines to lower the base metal temperature. During operation, the TBC may fail through, for example, fatigue. In this study, a TBC system deposited on a Ni-base alloy was tested in tensile bending fatigue. The TBC system was tested as-sprayed and oxidized, and two load levels were used. After interrupting the tests, at 10,000–50,000 cycles, the TBC tested at the lower load had extensive delamination damage, whereas the TBC tested at the higher load was relatively undamaged. At the higher load, the TBC formed vertical cracks which relieved the stresses in the TBC and retarded delamination damage. A finite element (FE) analysis was used to establish a likely vertical crack configuration (spacing and depth), and it could be confirmed that the corresponding stress drop in the TBC should prohibit delamination damage at the higher load.

Place, publisher, year, edition, pages
ASME Press, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-142274 (URN)10.1115/1.4037587 (DOI)000415791400010 ()2-s2.0-85029559590 (Scopus ID)
Available from: 2017-10-24 Created: 2017-10-24 Last updated: 2017-12-12Bibliographically approved
Jonnalagadda, K. P., Eriksson, R., Yuan, K., Li, X.-H., Ji, X., Yu, Y. & Peng, R. L. (2017). Comparison of Damage Evolution During Thermal Cycling in a High Purity Nano and Conventional Thermal Barrier Coating. Surface & Coatings Technology, 332, 47-56
Open this publication in new window or tab >>Comparison of Damage Evolution During Thermal Cycling in a High Purity Nano and Conventional Thermal Barrier Coating
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2017 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 332, p. 47-56Article in journal (Refereed) Published
Abstract [en]

Thermal barrier coatings (TBCs), consisting of a ceramic top coat and a metallic bond coat, offer resistance against high temperature degradation of turbine components. Cyclic oxidation of the bond coat, thermal stresses due to their thermal mismatches during cyclic operations, and sintering of the top coat are considered to be the common ways by which thermal barrier coatings fail. To reduce sintering, a nano structured high purity yttria stabilized zirconia (YSZ) was developed. The focus of this work is to compare the damage development of such high purity nano YSZ TBC during thermal cycling with a conventional YSZ TBC. Thermal cyclic fatigue (TCF) tests were conducted on both the TBC systems between 100 °C and 1100 °C with a 1 h hold time at 1100 °C. TCF test results showed that conventional YSZ TBC exhibited much higher life compared to the high purity nano YSZ TBC. The difference in the lifetime is explained by the use of microstructural investigations, crack length measurements along the cross-section and the difference in the elastic modulus. Furthermore, stress intensity factors were calculated in order to understand the difference(s) in the damage development between the two TBC systems.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
High purity nano, damage evolution, thermal cycling fatigue, crack length measurement, conventional TBC
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-142311 (URN)10.1016/j.surfcoat.2017.09.069 (DOI)000418968100007 ()2-s2.0-85030751243 (Scopus ID)
Note

Funding agencies: Vinnova in Sweden [2015-06870]

Available from: 2017-10-25 Created: 2017-10-25 Last updated: 2019-02-26Bibliographically approved
Calmunger, M., Eriksson, R., Chai, G., Johansson, S. & Moverare, J. (2017). Influence of Cyclic Oxidation in Moist Air on Surface Oxidation-Affected Zones. In: : . Paper presented at EUROMAT17, Thessaloniki 17-21 September 2017,Greece (pp. 1-1).
Open this publication in new window or tab >>Influence of Cyclic Oxidation in Moist Air on Surface Oxidation-Affected Zones
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2017 (English)Conference paper, Oral presentation with published abstract (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-143972 (URN)
Conference
EUROMAT17, Thessaloniki 17-21 September 2017,Greece
Available from: 2018-01-01 Created: 2018-01-01 Last updated: 2018-01-16Bibliographically approved
Calmunger, M., Eriksson, R., Chai, G., Johansson, S., Högberg, J. & Moverare, J. (2017). Local Surface Phase Stability During Cyclic Oxidation Process. Paper presented at THERMEC'16, May 30 - June 3, 2016, Graz, Austria. Materials Science Forum, 879, 855-860
Open this publication in new window or tab >>Local Surface Phase Stability During Cyclic Oxidation Process
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2017 (English)In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 879, p. 855-860Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Trans Tech Publications, 2017
Keywords
Austenitic stainless steels, thermal cycling, corrosion, surface phase stability
National Category
Materials Engineering
Identifiers
urn:nbn:se:liu:diva-129244 (URN)10.4028/www.scientific.net/MSF.879.855 (DOI)
Conference
THERMEC'16, May 30 - June 3, 2016, Graz, Austria
Available from: 2016-06-14 Created: 2016-06-14 Last updated: 2017-11-28
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