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Publications (10 of 81) Show all publications
Shao, X., Ringsberg, J. W., Yao, H.-D., Li, Z., Johnson, E. & Fredriksson, G. (2023). A comparison of two wave energy converters’ power performance and mooring fatigue characteristics – One WEC vs many WECs in a wave park with interaction effects. Journal of Ocean Engineering and Science
Open this publication in new window or tab >>A comparison of two wave energy converters’ power performance and mooring fatigue characteristics – One WEC vs many WECs in a wave park with interaction effects
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2023 (English)In: Journal of Ocean Engineering and ScienceArticle in journal (Refereed) Epub ahead of print
Abstract [en]

The production of renewable energy is key to satisfying the increasing demand for energy without further increasing pollution. Harnessing ocean energy from waves has attracted attention due to its high energy density. This study compares two generations of floating heaving point absorber WEC, WaveEL 3.0 and WaveEL 4.0, regarding their power performance and mooring line fatigue characteristics, which are essential in, e.g., LCoE calculations. The main differences between the two WECs are the principal dimensions and minor differences in their geometries. The DNV software SESAM was used for simulations and analyses of these WECs in terms of buoy heave motion resonances for maximising energy harvesting, motion characteristics, mooring line forces, fatigue of mooring lines, and hydrodynamic power production. The first part of the study presents results from simulations of unit WEC in the frequency domain and in the time domain for regular wave and irregular sea state conditions. A verification of the two WECs’ motion responses and axial mooring line forces is made against measurement data from a full-scale installation. In the second part of the study, the influence of interaction effects is investigated when the WECs are installed in wave parks. The wave park simulations used a fully-coupled non-linear method in SESAM that calculates the motions of the WECs and the mooring line forces simultaneously in the time domain. The amount of fatigue damage accumulated in the mooring lines was calculated using a relative tension-based fatigue analysis method and the rainflow counting method. Several factors that influence the power performance of the wave park and the accumulated fatigue damage of the mooring lines, for example, the WEC distance of the wave park, the sea state conditions, and the direction of incoming waves, are simulated and discussed. The study's main conclusion is that WaveEL 4.0, which has a longer tube than WaveEL 3.0, absorbs more hydrodynamic energy due to larger heave motions and more efficient power production. At the same time, the accumulated fatigue damage in the moorings is lower compared to WaveEL 3.0 if the distance between the WECs in the wave park is not too short. Its motions in the horizontal plane are larger, which may require a larger distance between the WEC units in a wave park to avoid losing efficiency due to hydrodynamic interaction effects.

National Category
Marine Engineering
Identifiers
urn:nbn:se:ri:diva-66490 (URN)10.1016/j.joes.2023.07.007 (DOI)
Note

This work was performed within the projects ’Control of wave energy converters based on wave measurements, for optimal energy absorption’, funded by the Swedish Energy Agency through contract agreement no. 50197-1, and ‘INTERACT—Analysis of array systems of wave energy converters with regard to interaction effects in the LCoE and fatigue analyses’, funded by the Swedish Energy Agency through contract agreement no. 50148-1. 

Available from: 2023-09-20 Created: 2023-09-20 Last updated: 2023-09-20Bibliographically approved
Larsson, J., Johansson, F., Ivars, D., Johnson, E., Flansbjer, M. & Williams Portal, N. (2023). A novel method for geometric quality assurance of rock joint replicas in direct shear testing – Part 1: Derivation of quality assurance parameters and geometric reproducibility. Journal of Rock Mechanics and Geotechnical Engineering
Open this publication in new window or tab >>A novel method for geometric quality assurance of rock joint replicas in direct shear testing – Part 1: Derivation of quality assurance parameters and geometric reproducibility
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2023 (English)In: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755Article in journal (Refereed) Epub ahead of print
Abstract [en]

Since each rock joint is unique by nature, the utilization of replicas in direct shear testing is required to carry out experimental parameter studies. However, information about the ability of the replicas to simulate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking. With the aim to facilitate generation of high-quality direct shear test data from replicas, a novel component in the testing procedure is introduced by presenting two parameters for geometric quality assurance. The parameters are derived from surface comparisons of three-dimensional (3D) scanning data of the rock joint and its replicas. The first parameter, σmf, captures morphological deviations between the replica and the rock joint surfaces. σmf is derived as the standard deviation of the deviations between the coordinate points of the replica and the rock joint. Four sources of errors introduced in the replica manufacturing process employed in this study could be identified. These errors could be minimized, yielding replicas with σmf ≤ 0.06 mm. The second parameter is a vector, VHp100, which describes deviations with respect to the shear direction. It is the projection of the 100 mm long normal vector of the best-fit plane of the replica joint surface to the corresponding plane of the rock joint. |VHp100| was found to be less than or equal to 0.36 mm in this study. Application of these two geometric quality assurance parameters demonstrates that it is possible to manufacture replicas with high geometric similarity to the rock joint. In a subsequent paper (part 2), σmf and VHp100 are incorporated in a novel quality assurance method, in which the parameters shall be evaluated prior to direct shear testing. Replicas having parameter values below established thresholds shall have a known and narrow dispersion and imitate the shear mechanical behavior of the rock joint.

Place, publisher, year, edition, pages
Chinese Academy of Sciences, 2023
Keywords
Geometric quality assurance, Geometric reproducibility, Replicas, Rock joint, Surface comparisons, Three-dimensional (3D) scanning
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-63984 (URN)10.1016/j.jrmge.2022.12.011 (DOI)2-s2.0-85147379920 (Scopus ID)
Note

Correspondence Address: Larsson, J, RISE, Sweden; email: jorgen.larsson@ri.se; Funding details: BeFo 391; Funding details: Nuclear Waste Management Organization, NWMO; Funding text 1: The authors would like to acknowledge the financial contribution received from BeFo Rock Engineering Research Foundation (Grant proposal BeFo 391); Nuclear Waste Management Organization (NWMO) , Toronto, Canada and Swedish Nuclear Fuel and Waste Management Co. ( SKB ), Solna, Sweden. The authors also would like to acknowledge Jörgen Spetz at the Department of Measurement Technology at Research Institutes of Sweden (RISE) for performing the scanning.

Available from: 2023-02-16 Created: 2023-02-16 Last updated: 2023-07-06Bibliographically approved
Larsson, J., Johansson, F., Ivars, D. M., Johnson, E., Flansbjer, M. & Williams Portal, N. (2023). A novel method for geometric quality assurance of rock joint replicas in direct shear testing : Part 2: Validation and mechanical replicability. Journal of Rock Mechanics and Geotechnical Engineering
Open this publication in new window or tab >>A novel method for geometric quality assurance of rock joint replicas in direct shear testing : Part 2: Validation and mechanical replicability
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2023 (English)In: Journal of Rock Mechanics and Geotechnical Engineering, ISSN 1674-7755Article in journal (Refereed) Epub ahead of print
Abstract [en]

Each rock joint is unique by nature which means that utilization of replicas in direct shear tests is required in experimental parameter studies. However, a method to acquire knowledge about the ability of the replicas to imitate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking. In this study, a novel method is presented for geometric quality assurance of replicas. The aim is to facilitate generation of high-quality direct shear testing data as a prerequisite for reliable subsequent analyses of the results. In Part 1 of this study, two quality assurance parameters, σmf and VHp100, are derived and their usefulness for evaluation of geometric deviations, i.e. geometric reproducibility, is shown. In Part 2, the parameters are validated by showing a correlation between the parameters and the shear mechanical behavior, which qualifies the parameters for usage in the quality assurance method. Unique results from direct shear tests presenting comparisons between replicas and the rock joint show that replicas fulfilling proposed threshold values of σmf < 0.06 mm and < 0.2 mm have a narrow dispersion and imitate the shear mechanical behavior of the rock joint in all aspects apart from having a slightly lower peak shear strength. The wear in these replicas, which have similar morphology as the rock joint, is in the same areas as in the rock joint. The wear is slightly larger in the rock joint and therefore the discrepancy in peak shear strength derives from differences in material properties, possibly from differences in toughness. It is shown by application of the suggested method that the quality assured replicas manufactured following the process employed in this study phenomenologically capture the shear strength characteristics, which makes them useful in parameter studies.

Keywords
Three-dimensional (3D) scanning, Contact area measurements, Direct shear testing, Geometric quality assurance, Mechanical replicability, Replicas, Rock joint
National Category
Civil Engineering
Identifiers
urn:nbn:se:ri:diva-64280 (URN)10.1016/j.jrmge.2022.12.012 (DOI)
Note

The authors would like to acknowledge the financial contribution received from BeFo Rock Engineering Research Foundation (Grant proposal BeFo 391); Nuclear Waste Management Organization (NWMO), Toronto, Canada and Swedish Nuclear Fuel and Waste Management Co. (SKB), Solna, Sweden. 

Available from: 2023-03-30 Created: 2023-03-30 Last updated: 2023-07-03Bibliographically approved
Ringsberg, J., Kuznecovs, A. & Johnson, E. (2023). Analysis of how the conditions in a collision scenario affect the size of a struck vessel’s damage opening and ultimate strength. In: C. Guedes Soares and Ringsberg J.W. (Ed.), Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023) : . Paper presented at Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023 (pp. 639-647).
Open this publication in new window or tab >>Analysis of how the conditions in a collision scenario affect the size of a struck vessel’s damage opening and ultimate strength
2023 (English)In: Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023)  / [ed] C. Guedes Soares and Ringsberg J.W., 2023, p. 639-647Conference paper, Published paper (Refereed)
National Category
Vehicle Engineering
Identifiers
urn:nbn:se:ri:diva-64284 (URN)
Conference
Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023
Available from: 2023-04-06 Created: 2023-04-06 Last updated: 2023-04-06Bibliographically approved
Kuznecovs, A., Ringsberg, J., Mallaya Ullal, A., Janardhana Bangera, P. & Johnson, E. (2023). Consequence analyses of collision-damaged ships — damage stability, structural adequacy and oil spills. Ships and Offshore Structures, 18(4), 567
Open this publication in new window or tab >>Consequence analyses of collision-damaged ships — damage stability, structural adequacy and oil spills
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2023 (English)In: Ships and Offshore Structures, ISSN 1744-5302, E-ISSN 1754-212X, Vol. 18, no 4, p. 567-Article in journal (Refereed) Published
Abstract [en]

A ship collision accident may pose a threat to human lives, the environment and material assets. A damaged ship can suffer from the loss of ship stability, reduced global structural strength, and the loss of the integrity of internal tanks carrying polluting liquids. This study presents a methodology as a framework that can be used to analyze the related consequences of ship-ship collision events using simulations and evaluations. The methodology includes nonlinear finite element analyses of the collision event, a METOCEAN data analysis module, damage stability simulations, analyses of the damaged ship’s ultimate strength and structural integrity, oil spill drift simulations, and finally, an evaluation of the three abovementioned consequences. A case study with a chemical tanker subjected to collision demonstrates the methodology. The collision event was assumed to occur in the Kattegat area (between Sweden and Denmark) at a ship route intersection with high ship traffic density. © 2022 The Author(s).

Place, publisher, year, edition, pages
Taylor and Francis Ltd., 2023
Keywords
Consequence analysis, damage stability, oil spill, ship collision, ultimate strength, Oil tankers, Stability, Collision events, Collision/accident, Damaged ships, Human lives, Non-linear finite elements, Structural strength, Oil spills
National Category
Transport Systems and Logistics
Identifiers
urn:nbn:se:ri:diva-59346 (URN)10.1080/17445302.2022.2071014 (DOI)2-s2.0-85130285888 (Scopus ID)
Note

This study received financial support from the Swedish Transport Administration project ‘SHARC - Structural and Hydro mechanical Assessment of Risk in Collision and grounding’ (grant agreement: TRV 2019/42277). The FEAs were partly performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at Chalmers Centre for Computational Science and Engineering (C3SE) partially funded by the Swedish Research Council through grant agreement no. 2018-05973.

Available from: 2022-06-13 Created: 2022-06-13 Last updated: 2023-07-07Bibliographically approved
Shao, X., Ringsberg, J., Yao, H.-D., Li, Z. & Johnson, E. (2023). Fatigue of mooring lines in wave energy parks. In: C. Guedes Soares and Ringsberg J.W. (Ed.), Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023) : . Paper presented at Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023 (pp. 205-211).
Open this publication in new window or tab >>Fatigue of mooring lines in wave energy parks
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2023 (English)In: Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023)  / [ed] C. Guedes Soares and Ringsberg J.W., 2023, p. 205-211Conference paper, Published paper (Refereed)
National Category
Marine Engineering
Identifiers
urn:nbn:se:ri:diva-64286 (URN)
Conference
Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023
Available from: 2023-04-06 Created: 2023-04-06 Last updated: 2023-04-06Bibliographically approved
Li, Z., Ringsberg, J., Serdyuk, Y., Svensson, D., Johnson, E. & Andersson, C. (2023). Predicting failure of dynamic subsea cables by electrical insulation breakdown due to water treeing. In: C. Guedes Soares and Ringsberg J.W. (Ed.), Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023) : . Paper presented at Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023 (pp. 477-484).
Open this publication in new window or tab >>Predicting failure of dynamic subsea cables by electrical insulation breakdown due to water treeing
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2023 (English)In: Proceedings of the Ninth International Conference on Marine Structures (MARSTRUCT2023)  / [ed] C. Guedes Soares and Ringsberg J.W., 2023, p. 477-484Conference paper, Published paper (Refereed)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-64285 (URN)
Conference
Ninth International Conference on Marine Structures (MARSTRUCT2023) in Gothenburg, Sweden, April 3-5, 2023
Note

WATERTREE – Predicting failure of dynamic subsea cables by insulation breakdownSwedish Energy Agency (50156-1), 2020-09-01 -- 2022-03-31

Available from: 2023-04-06 Created: 2023-04-06 Last updated: 2023-05-22Bibliographically approved
Shao, X., Yao, H., Ringsberg, J. W., Li, Z., Johnson, E. & Fredriksson, G. (2022). A comparison of the performance and characteristics of two generations Waves4Power WaveEL wave energy converters. In: Proceedings of The 5th International Conference on Renewable Energies Offshore (RENEW 2022); 2022 November 8-10; Lisbon, Portugal: Trends in Renewable Energies Offshore. Paper presented at 5th International Conference on Renewable Energies Offshore (RENEW 2022); 2022 November 8-10; Lisbon, Portugal (pp. 277-284).
Open this publication in new window or tab >>A comparison of the performance and characteristics of two generations Waves4Power WaveEL wave energy converters
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2022 (English)In: Proceedings of The 5th International Conference on Renewable Energies Offshore (RENEW 2022); 2022 November 8-10; Lisbon, Portugal: Trends in Renewable Energies Offshore, 2022, p. 277-284Conference paper, Published paper (Refereed)
Keywords
Engineering and Technology, Teknik och teknologier
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-61468 (URN)
Conference
5th International Conference on Renewable Energies Offshore (RENEW 2022); 2022 November 8-10; Lisbon, Portugal
Note

Research Project: Control of wave energy converters based on wave measurements, for optimal energy absorption (WAVEMEASURE)Swedish Energy Agency (50197-1), 2020-09-01 -- 2023-03-31

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2022-12-07Bibliographically approved
Shao, X., Yao, H., Ringsberg, J. W., Li, Z. & Johnson, E. (2022). A comparison of the performance of two generations Waves4Power WaveEL wave energy converters in a hexagon-shaped array farm. In: Proceedings of the International Conference on Ships and Offshore Structures ICSOS 2022, 17-19 October 2022, Ålesund, Norway.: . Paper presented at International Conference on Ships and Offshore Structures ICSOS 2022, 17-19 October 2022, Ålesund, Norway..
Open this publication in new window or tab >>A comparison of the performance of two generations Waves4Power WaveEL wave energy converters in a hexagon-shaped array farm
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2022 (English)In: Proceedings of the International Conference on Ships and Offshore Structures ICSOS 2022, 17-19 October 2022, Ålesund, Norway., 2022Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-61467 (URN)
Conference
International Conference on Ships and Offshore Structures ICSOS 2022, 17-19 October 2022, Ålesund, Norway.
Note

Research Project: Control of wave energy converters based on wave measurements, for optimal energy absorption (WAVEMEASURE)Swedish Energy Agency (50197-1), 2020-09-01 -- 2023-03-31.

Available from: 2022-12-07 Created: 2022-12-07 Last updated: 2022-12-07Bibliographically approved
Li, Z., Ringsberg, J. W., Johnson, E. & Serdyuk, Y. (2022). Crack Propagation in Dynamic Power Cables. In: Proceedings of the ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE2022) : . Paper presented at ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE2022) in Hamburg, Germany, June 5-10, 2022,. , Article ID OMAE2022‑79467.
Open this publication in new window or tab >>Crack Propagation in Dynamic Power Cables
2022 (English)In: Proceedings of the ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE2022) , 2022, article id OMAE2022‑79467Conference paper, Published paper (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:ri:diva-60127 (URN)
Conference
ASME 2022 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE2022) in Hamburg, Germany, June 5-10, 2022,
Available from: 2022-09-16 Created: 2022-09-16 Last updated: 2022-09-16Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-7182-0872

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