Sören Ehlers

Profilbilde
Epostsoren.ehlers@ntnu.no
Fasttelefon 73595596
Mobiltelefon 91897748
KontoradresseMarinteknisk senter*E2.232, Otto Nielsens veg 10
StillingProfessor
EnhetInstitutt for marin teknikk


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The world wide increasing trend and interest in the Arctic Sea requires sound design concepts and regulations to cope with the distinct regional challenges in order to make northern transport feasible. Therefore, I am developing a holistic design environment for ships operating in Arctic conditions and thereby assess the vessels´ performance and strength operating in ice, which can further be used to assess and minimize the operational risk as well as the environmental and global cost.

Basic research

  • Fluid-Ice-Structure Interaction suitable for optimization
  • New materials and structures
  • Methods to assess the environmental impact and cost of transport systems for the Arctic Sea

Applied research

  • Design methods for Arctic Sea transport systems
  • Sustainable and competitive concepts
  • Innovative solutions for operations in Arctic conditions
  • Active and passive safety features
  • Design requirements to fulfil the demands for the northern passages in the future

Within both research areas I would like to develop a close industrial cooperation to support innovative products with state of the art research results. Additionally, direct feedback from industrial partners working in the Arctic Sea region will be highly appreciated to strengthen the overall competitiveness through innovative strategies and designs.

 

 

Publications

Journal articles

  • Ehlers S. A Particle Swarm Algorithm-Based Optimization for High-Strength Steel Structures. Journal of Ship production and Design, 2012; 28 (1); 1-9.
  • von Bock und Polach RUF, Ehlers S. Heave and pitch motions of a ship inmodel ice: an experimental study on ship resistance and ice breaking pattern. Cold Regions Science and Technology, 2011; 68; 49-59.
  • Ehlers, S. A review of collision and grounding damage assessment method. Marine Systems & Ocean Technology, 2011; 6(1); 5-15.
  • Ehlers S, Remes H, Klanac A, Naar H. A multi-objective optimisation-based structural design procedure for the concept stage - a chemical product tanker case study. Ship Technology Research, Schiffstechnik, 2010; 57(3): 182-197.
  • Ehlers S. Optimisation for Crashworthiness. Brodogradnja-Shipbuilding 2010; 61(4): 341-346.
  • Rigo P, Žanić V, Ehlers S, Andrić J. Design of Innovative Ship Concepts using an Integrated Decision Support System for Ship Production and Operation. Brodogradnja-Shipbuilding 2010; 61(4): 367-381.
  • Ehlers S, Tabri K, Romanoff J, Varsta P. Numerical and Experimental Investigation on the Collision Resistance of the X-core Structure. Journal of Ships and Offshore Structures, Special Issue on Collision and Grounding, 2010; xx(xx), 1–9.
  • Ehlers S. A procedure to assess the damage of a grounded ship: a full-scale validation case study. Ship Technology Research, 2010; 57(1); 50-64.
  • Ehlers S. The influence of the material relation on the accuracy of collision simulations. Marine Structures, 2010; 23; 462-474.
  • Kõrgesaar M, Ehlers S. An Assessment Procedure of the Crashworthiness of an LNG Tanker Side Structure. Ship Technology Research, Schiffstechnik, 2010; 57(1): 50-64.
  • Ehlers S. A procedure to optimize ship side structures for crashworthiness. Journal of Engineering for the Maritime Environment 2009; 224: 1-12.
  • Ehlers S. Strain and stress relation until fracture for finite element simulations of a thin circular plate. Thin-Walled Structures 2009; 48(1); 1-8.
  • Klanac A, Ehlers S, Jelovica J. Optimization of crashworthy marine structures, Marine Structures 2009; 22(4); 670-690.
  • Ehlers S, Varsta P. Strain and stress relation for non-linear finite element simulations. Thin-Walled Structures 2009; 47; 1203-1217.
  • Ehlers S, Broekhuijsen J, Alsos HS, Biehl F, Tabri K. Simulating the collision response of ship side structures: A failure criteria benchmark study. Int Ship Progress 2008; 55: 127-144.

Guest editor

  • Wang G, Ehlers S. Special Issue on Collision and Grounding of Ships. Journal of Ships and Offshore structures.

Invited speaker

  • Ports for Container Ships of Future Generations, Workshop, TUHH, 2011. Grounding and Collision of Ships - a state of the art review, pp. 123-136.
Conference proceedings
  • 5th International Conference on Collision and Grounding of Ships edited by Ehlers S, Romanoff J. 2010. 263 pages.

Summary articles

  • Ehlers S, Tabri K, Varsta P. Collision strength of Ship Structures – A state of the art review. To appear in: CENTEC (Lisbon) 15th anniversary book 2009/10.

Conference articles

  • Ståhlberg K, Ehlers S, Kujala P. Design scenario modeling for assessing passenger vessel crashworthiness. IMDC2012
  • Storheim M, Kim E, Amdahl J, Ehlers S. Iceberg shape sensitivity in ship impact assessment in view of existing material models. OMAE2012
  • von Bock und Polach R, Janardanan V, Ehlers S. Ice model tests in context of the investment value of an offshore vessel. OMAE2012
  • Tabri K, Ehlers S, Korgesaar M, Ståhlberg K, Heinvee M. Collision consequence assessment of ROPAX vessels operating in the Baltic Sea. OMAE2012
  • Erikstad SO, Ehlers S. A Decision Support Framework for Exploiting Northern Sea Route Transport Opportunities. Compit 2012.
  • Jelovica J, Romanoff J, Ehlers S, Aromaa A. Experimental investigation on ultimate strength of corroded web-core sandwich panel stripes, International conference on composite materials (ICCM 18), 21-26 August 2011, Jeju, Korea.
  • Montewka J, Goerlandt F, Ehlers S, Kujala P, Erceg S, Polic D, Klanac A, Hinz T, Tabri K. A model for consequence evaluation of ship-ship collision based on Bayesian Belief Network. In Rizutto&Guedes Soares (eds), Sustainable Maritime Transportation and Exploation of Sea Resources, Taylor&Francis, London, 2011; 721-728.
  • Ehlers S. A Particle Swarm Algorithm-Based Optimisation for High- Strength Steel Structures. COMPIT 2011.
  • Ehlers S, Klanac A, Schröder M. An investigation of a Suezmax tanker grounding accident. Hamburg, Deutschland. Marstruct 2011.
  • D. Polić, D. Frank, A. Klanac, S. Ehlers. Finite element-based shape optimization of an asymmetric steel sandwich panel joint. Marstruct 2011.
  • Montewka J, Ehlers S, Tabri K. Elements of risk analysis for LNG tanker maneuvering with tug assistance in a harbor. 11th Symposium on Practical Design of Ships and Other Floating Structures, Rio de Janeiro, Brasil 2010.
  • Frank D, Klanac A, Kniep M, Polić, Ehlers S. Optimization system for design of laser-welded steel-sandwich structures. 11th Symposium on Practical Design of Ships and Other Floating Structures, Rio de Janeiro, Brasil 2010.
  • Ehlers S, Tabri K, Romanoff J, Varsta P. Numerical and Experimental Investigation on the Collision Resistance of the X-core Structure. 5th Intl. Conference on Collision and Grounding of Ships. 2010; 18-24.
  • Ehlers, S. A material relation for ship collision simulations. 5th Intl. Conference on Collision and Grounding of Ships. 2010; 113-117.
  • Klanac A, Duletić T, Erceg S, Ehlers S, Frank D. Environmental risk of collisions in the enclosed European waters: Gulf of Finland, Northern Adriatic and the implications for tanker design. 5th Intl. Conference on Collision and Grounding of Ships. 2010; 55-65.
  • Varsta P, Ehlers S, Klanac A, Tabri K. Collision and Grounding of Ship Structures. In Advanced Ship Design for Pollution Prevention. 2010; 191-204.
  • Ehlers S. Optimization for Crashworthiness. 10th Finnisch Mechanics Days. Jyväskylä, Finland. 2009; 85-93.
  • Ehlers S, Klanac A, Remes H, Kapuścik K, Naar H, Andric J, Zanic V, Grgic M, Pircalabu, E, Bair F. The IMPROVEd chemical tanker. IMPROVE-Conference, Dubrovnik, Kroatien. 2009; 136-145.
  • Ehlers S, Kapuścik K, Khalid H, Turan O. The basic design, performance and stability of the IMPROVEd chemical tanker. IMPROVE-Conference, Dubrovnik, Kroatien. 2009; 131-135.
  • Remes H, Klanac A, Varsta P, Ehlers S. ConStruct – Platform for Conceptual Structural Design. IMPROVE-Conference, Dubrovnik, Kroatien. 2009; 86-91.
  • Ehlers S, Klanac A, Kõrgesaar M. A design procedure for structures against impact loading. Vorgetragen in der Jahreshauptversammlung der Schiffbautechnischen Gesellschaft in Hamburg 2008, die schriftliche Fassung erschien im Jahrbuch 2008.
  • Ehlers S, Klanac A, Tabri K. Increased safety of a tanker and a RO-PAX vessel by implementing a novel sandwich structure. 4th Intl. Conference on Collision and Grounding of Ships. Germany, 2007; 109-115.
  • Tabri K, Alsos H, Broekhuijsen J, Ehlers S. A benchmark study on ductile failure criteria for shell elements in multiaxial stress state. Advancements in Marine Structures. 2007; 401-409.
  • Ehlers S, Tabri K, Schillo N, Ranta J. Implementation of a novel ship side structure into a tanker and a ropax vessel for increased crashworthiness. 6th European LS-DYNA Users' Conference, Gothenburg, Sweden. 2007; 4.111-4.120.
  • Klanac A, Tabri K, Ehlers S, Nekic A. Multi-Attribute Design of Crashworthy Structures in the Bi-Stakeholder Environment, International Marine Design Conference – IMDC, Ann Arbor, 2006.
  • Ehlers S. Design of steel sandwich panel joints with respect to fatigue life. Sommertagung der Schiffbautechnischen Gesellschaft in Stettin 2004. Erschienen im Jahrbuch 2006, Band 98, ISBN 3-540-27423-5.
  • Klanac A, Ehlers S, Tabri K, Rudan S, Broekhuijsen J. Qualitative design assessment of crashworthy structures. Proc Int Maritime Association of Mediterranean, Portugal. 2005; 461-469.
  • Klanac A, Ehlers S, Tabri K. Analysis of crashworthy structures. Maritime Research News 2005, Vol. 20.
  • Ehlers S. Design of steel sandwich panel joints. Ship structural design seminar, Espoo, Finland 2005.
  • Kujala P, Romanoff J, Tabri K, Ehlers S. All Steel Sandwich Panels – Design Challenges for Practical Applications on Ships. 9th Symposium on Practical Design of Ships and Other Floating Structures, Lübeck-Travemünde, Deutschland 2004.

Reports

  • Jelovica J, Romanoff J, Ehlers S, Remes H. Ultimate strength tests of corroded web-core and corrugated-core sandwich beams. Aalto University, Dept. of Applied Mechanics. Research Report 2011. http://lib.tkk.fi/SCIENCE_TECHNOLOGY/2011/isbn9789526044347.pdf

  • Ehlers S, Enquist B. Uni axial tensile necking of steel dog-bone specimens. Helsinki University of Technology, Ship Laboratory, M-303, 2007.

  • Ehlers S. A thin circular plate under hemi-spherical punch; An experimental study of a plate subjected to a displacement controlled punch. Helsinki University of Technology, Department of Applied Mechanics, TKK-AM-7, 2009.

Books with societal impact

  • Guedes Soares C, Parunov J, Blagojević B, Grubišić R, Zamarin A, Žiha K, Ehlers S, Klanac A, Tokić G. Experience and Sustainability of International Curriculum Development in Naval Architecture. 2010. 88 pages, ISBN 978-953-7738-00-6.
  • Grubišić R, Prpić-Oršić J, Parunov J, Ehlers S, Kujala P, Guedes Soares C. Advanced Studies of Naval Architecture in Croatia, Finland and Portugal. 2010. 125 pages, ISBN 978-953-7738-01-3.