Dynamic Marine Component (DMaC) Test Facility

The Dynamic Marine Component (DMaC) test facility is a purpose built test rig that aims to replicate the forces and motions experienced by marine components in offshore applications. The test facility is based within the Renewable Energy Research Group of the University of Exeter at Penryn Campus, Cornwall.

Introduction to DMaC

The test rig consists of a linear hydraulic cylinder at the tailstock that applies the tension and compression forces or displacements. At the other end of the rig, the headstock with three degrees of freedom can apply bending moments (torque) and angular displacements. The combination of forces and motions from the headstock and tailstock simulate the loads and displacements experienced by a floating body. The working principles are illustrated in figure 1 below. For example, the tailstock can replicate heave motion (Z) and the headstock can replicate pitch (Øx), roll (Øy) and yaw (Øz) motions.

The rig is capable of replicating dynamic tensile forces up to 20 tonnes, static tensile forces up to 40 tonnes, and displacements up to 1 m. The maximum bending angle at the headstock is ±30º for pitch and roll with up to 10 kN·m of bending moment. The maximum torque or yaw is 10 kN·m with an infinite rotational displacement. Beyond that, the rig has the unique feature that components can be submerged in fresh water to allow testing in a wet environment. These features allow dynamic testing of large-scale components under controlled conditions with realistic motion or load characteristics.

This unique combination of features have allowed the DMaC test facility to support studies in to a variety of marine components including: conventional mooring ropes, compliant mooring components, subsea power cables, bend restrictors for power cables, aquaculture components, power take off devices for MRE and even acoustic monitoring of components. These studies are commonly part of national and international collaborative projects and are used to inform performance characterisation, peak or fatigue load assessment, reliability studies and accelerated test campaigns. Furthermore, test work has been conducted to international standard.

Download the DMaC specification sheet

Working principles of the DMaC test rig:

	Heave	Pitch and Roll	Yaw
Force	400 kN (max)	10 kN-m	10 kN-m
Displacement	1m	30°	Infinite
Speed	0.1 m/s	120°	10rpm

Brochure

Click on the brochure to enlarge it and see it full screen. Alternatively, you can download a copy.

Example projects

DMaC test facility have performed a huge range of project with collaboration from varying industrial and academic partners. More details can be found in the brochure. The following is a list of example projects and below that are videos to accompany the example projects and case studies in the brochure:

Synthetic fibre robes
Highly compliant elastomeric mooring components
Mooring load control systems
Marine power cables
Cable bend restrictors and stifferners
Power take off devices
Conventional mooring components (e.g. chain and shackles)
Aquaculture components
Acoustic monitoring of marine components
General tension and bending assessments

Videos of our example projects:

Click on the links below to be redirected to a YouTube video demonstration [new window].

Publications list

The following is lists of the publications associated with work completed at DMaC test facility including 1) Conventional mooring lines, 2) Compliant, elastic mooring lines, 3) Subsea power cables and bend restrictors, 4) Reliability studies and 5) Acoustic monitoring.

1. Conventional mooring lines

Weller SD, Davies P, Johanning L., 2013. The influence of load history on synthetic rope response. EWTEC, Denmark, Proceedings of the 10th European Wave and Tidal Energy Conference.
Dorenbusch J, Canedo A, Leao A, Rodríguez Arias R, Glez. De Lena V, Johanning L, Thies PR, Parish D, Weller S., 2014. Fibre Ropes for Taut Mooring Lines for Marine Energy Converters. MARINET infrastructure access report: FibreTaut1.
Weller, S.D., Davies, P., Vickers, A.W. and Johanning, L., 2014. Synthetic rope responses in the context of load history: Operational performance. Ocean Engineering, 83, pp.111-124.
Dorenbusch J, Canedo A, Leao A, Rodríguez Arias R, Glez. De Lena V, Johanning L, Thies PR, Parish D, Weller S., 2015. Fibre Ropes for Taut Mooring Lines for Marine Energy Converters. MARINET infrastructure access report: FibreTaut2.
Rodríguez, A., Weller, S.D., Canedo, J., Rodríguez, R., González de Lena, V., Thies, P.R., Parish, D., Johanning, L. and Leão, A., 2015. Performance Comparison of Marine Renewable Energy Converter Mooring Lines Subjected to Real Sea and Accelerated Loads. 11th EWTEC conference.
Weller, S.D., Davies, P., Vickers, A.W. and Johanning, L., 2015. Synthetic rope responses in the context of load history: The influence of aging. Ocean Engineering, 96, pp.192-204.

2. Compliant, elastic mooring lines

Thies, P.R., Johanning, L. and McEvoy, P., 2014. A novel mooring tether for peak load mitigation: Initial performance and service simulation testing. International Journal of marine energy, 7, pp.43-56.
Gordelier, T., Parish, D., Thies, P.R. and Johanning, L., 2015. A Novel Mooring Tether for Highly-Dynamic Offshore Applications; Mitigating Peak and Fatigue Loads via Selectable Axial Stiffness. Journal of Marine Science and Engineering, 3(4), pp.1287-1310.
Gordelier, T., Parish, D., Thies, P.R. and Johanning, L., 2015. A novel mooring tether for highly-dynamic offshore applications; Mitigating Peak and Fatigue Loads via Selectable Axial Stiffness. ASRAnet 2014.
Parish, D.N., 2015. A novel mooring tether for highly dynamic offshore applications. Doctoral dissertation, University of Exeter.
Luxmoore, J.F., Grey, S., Newsam, D. and Johanning, L., 2016. Analytical performance assessment of a novel active mooring system for load reduction in marine energy converters. Ocean Engineering, 124, pp.215-225.
Luxmoore, J., Grey, S., Newsam, D., Thies, P.R. and Johanning, L., 2016, February. Performance assessment of a novel active mooring system for load reduction in marine energy converters. International Conference on Ocean Energy (ICOE).
Parish, D.N., Herduin, M., Thies, P.R., Gordelier, T. and Johanning, L., 2017. Reducing peak and fatigue mooring loads: A validation study for elastomeric moorings. In Eupopean Wave and Tidal Energy Conference Series, Cork, Ireland.
Gordelier, T., Parish, D., Thies, P.R., Weller, S., Davies, P., Le Gac, P.Y. and Johanning, L., 2018. Assessing the performance durability of elastomeric moorings: Assembly investigations enhanced by sub-component tests. Ocean Engineering, 155, pp.411-424.
Luxmoore, J.F., Thies, P.R., Grey, S., Newsam, D. and Johanning, L., 2018. Performance and reliability testing of an active mooring system for peak load reduction. Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment, 232(1), pp.130-140.

3. Subsea power cables and bend restrictors

Marta, M., Mueller-Schuetze, S., Ottersberg, H., Isus, D., Johanning, L. and Thies, P.R., 2015. Development of dynamic submarine MV power cable design solutions for floating offshore renewable energy applications.
Marta, M., Mueller-Schuetze, S., Ottersberg, H., Isus, D., Johanning, L. and Thies, P.R., 2015. Development of new highly dynamic power cables design solutions for floating offshore renewable energy applications. MARINET infrastructure access report: HDPC4FMEC.
Thies, P.R., Tuk, T., Tuk, M., Marta, M. and Mueller-Schuetze, S., 2016. Accelerated reliability testing of articulated cable bend restrictor for offshore wind applications. MARINET infrastructure access report: Bend restrictors.
Thies, P.R., Johanning, L., Bashir, I., Tuk, T., Tuk, M., Marta, M. and Müller-Schütze, S., 2016. Accelerated reliability testing of articulated cable bend restrictor for offshore wind applications. International Journal of Marine Energy, 16, pp.65-82.DMaC_Publications_List

4. Reliability Studies

Gordelier, T., Johanning, L. and Thies, P.R., 2013, October. Reliability verification of mooring components for floating marine energy converters. SHF Symposium.
Thies, P.R., Johanning, L., Gordelier, T., Vickers, A. and Weller, S., 2013, June. Physical component testing to simulate dynamic marine load conditions. In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers.
Thies, P.R., Johanning, L. and Gordelier, T., 2013. Component reliability testing for wave energy converters: Rationale and implementation. European Wave and Tidal Energy Conference.
Weller, S.D., Thies, P.R., Gordelier, T., Harnois, V., Parish, D. and Johanning, L., 2014. Navigating the valley of death: Reducing reliability uncertainties for marine renewable energy.
Thies, P.R., Johanning, L., Karikari-Boateng, K.A., Ng, C. and McKeever, P., 2015. Component reliability test approaches for marine renewable energy. Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability, 229(5), pp.403-416.
Weller SD, Thies PR, Gordelier T, Davies P, Johanning L., 2015. The role of accelerated testing in reliability prediction. 11th European Wave and Tidal Energy Conference EWTEC2015, France.
Weller, S.D., Thies, P.R., Gordelier, T. and Johanning, L., 2015. Reducing reliability uncertainties for marine renewable energy. Journal of Marine Science and Engineering, 3(4), pp.1349-1361.

5. Acoustic monitoring

Bashir, I., Walsh, J., Thies, P.R., Weller, S.D., Blondel, P. and Johanning, L., 2017. Underwater acoustic emission monitoring - Experimental investigations and acoustic signature recognition of synthetic mooring ropes. Applied Acoustics, 121, pp.95-103.

Certification and Standards

Certification

The Quality Management System of DMaC test facility is accredited to ISO 9001:2015 by the British Standards Institute. The accreditation is applicable to:

THE DESIGN, TEST AND REPORT ON EXPERIMENTAL SERVICES OF MARINE COMPONENTS.

Quality Policy - The management team of the Dynamic Marine Component (DMaC) test facility aims to consistently provide a high-quality experimental service that meets or exceeds the clients’ requirements by:

Operating at the greatest achievable accuracy of driving parameters (i.e. requested forces and motions), boundary conditions and measurements.
Ensure traceability for critical processes, such as calibration and data analysis.
Prioritises safety of personnel and equipment.
Continual improvement of quality through process and equipment evaluation and enhancement.
Implementing and maintaining a quality management system certified against BS EN ISO 9001:2015.

Standards

The DMaC test rig aims to provide a Class 1 uniaxial testing machine, according to ISO 7500-1:2004. Class 1 test machines have relative errors of accuracy and repeatability less than ±1% and 1% respectively.
Test work has been conducted to international standards. For example, fibre ropes for offshore stationkeeping (ISO 19336:2015 and ISO 18692:2007) and subsea power cables (DNV-RP-F401 and Cigre Technical Brochure 623).

Certification and Standards list as shown above if required.

Contact details

Please contact the DMaC team to discuss your experimental requirements: