Smart Rocking Armour Units

Conference object English OPEN
Hofland, B. ; Arefin, Syed Shamsil ; van der Lem, Cock ; van gent, Marcel (2018)

This paper describes a method to measure the rocking motion of lab-scale armour units. Sensors as found in mobile phones are used. These sensors, data-storage and battery are all embedded in the model units, such that they can be applied without wires attached to them. The technique is applied to double-layer units in order to compare the results to the existing knowledge for this type of armour layers. In contrast to previous research, the gyroscope reading is used to determine the (rocking) impact velocities. Two pioneer measurement series are described. From the readings both the temporal distribution of rocking can be inferred, as well as the spatial distribution. The temporal probability distribution for the rocking events seems logarithmic, with the impact velocity u2% being in the same order of magnitude as those reported earlier. These measurements indicate that for a randomly placed cube in an armour layer most rocking and most violent impact velocities occur about 2Dn under the waterline, instead of around the waterline. Moreover, the wave steepness is seen to have an effect on the rocking intensity. From the measurements with multiple units it can be seen that the measured impact velocity exhibits a large spatial variation among different units at an otherwise equal location.
  • References (9)

    Arefin, S.S. (2017) Rocking Revisited 2 - Measurement on Rocking of cubes in a Double Layer on a Breakwater. MSc Thesis. TUDelft.

    Burcharth, H.F. (1992) Design of rubble mound breakwaters: Structural Integrity. In: Design and Reliability of Coastal Structures. Short course, 23rd ICCE, Venice.

    CUR (1989) Golfbrekers. Sterkte Betonnen Afdekelementen. Integratie van Fasen 1-3. Verslag werkgroep 1. Civiel Centrum Uitvoering Research en Regelgeving. In Dutch.

    CUR (1990a) Golfbrekers. Sterkte Betonnen Afdekelementen. Samenvatting onderzoek. Verslag werkgroep 1. Civiel Centrum Uitvoering Research en Regelgeving. In Dutch.

    CUR (1990b) Golfbrekers. Sterkte Betonnen Afdekelementen. Toepassingen. Verslag werkgroep 1. Civiel CentrumUitvoering Research en Regelgeving. In Dutch.

    Garcia, N., S. Richardson, T. Rigden (2013) Physical Model Testing of the Hydraulic Stability of Single-layer Armour Units. Proceedings of the Coasts, Marine Structures and Breakwaters 2013 Conference, ICE. Edinburgh, UK.

    Le, T.N. (2016) Rocking of a single cube on a breakwater slope. MSc Thesis. Delft: Delft University of Technology Sokolewicz, M. J. (1986) Impulsive loads for cubes and tetrapods in consequence of rocking during wave attack. MSc Thesis. Delft University of Technology. In Dutch: Impulsbelastingen voor kubussen en tetrapodes als gevolg van rocking bij golfaanval.

    Van der Meer J.W. and Heydra, G. (1991) Rocking armour units: Number, Location and Impact Velocity. Coastal Engineering 15, 1991.

    Zwanenburg, S.; Uijttewaal, W.S.J., Ten Oever, E., Muttray, M. (2013) The Influence of the Wave Height Distribution on the Stability of Interlocking Single Layer Armour Units. Proc. ICE Breakwaters conference. Edinburgh

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