The purpose of this MSc thesis is to do an experimental study into the spatial and temporal variation of rocking armour units. Armour units on a breakwater slope under wave loading can sometimes start to move back and forth, this phenomenon is known as rocking. Rocking can lead to significant impacts between armour units, which can result in breakage. This is especially important for single layer armour units, like the Xbloc. The development of the smart Xbloc makes it possible to measure accelerations and angular velocity with a stand alone sensors at a sampling frequency of around 100 Hz. The current literature does not provide the spatial distribution of the number of impacts and the impact velocities due to rocking. Furthermore, only limited knowledge is available on the distribution in time. The research aim of this thesis is: Determining the spatial and temporal distribution of the number of moving armour units, the number of impacts and the impact velocity of rocking armour units. To achieve this aim a physical scale model was set up and model tests have been performed with 10 smart Xbloc units to measure rocking. The collected data, analysis and results provide a unique look into the behaviour of single layer armour units. The results can be used to validate rocking models and provide valuable statistical information on the number of impacts and the impact velocities.

The concrete armour unit industry exist for more than 70 years, in this period various units were developed. The first units derived their hydraulic stability on their own weight, later the units got more complex shapes and got interlocking capabilities. The first interlocking units were placed in a two-layer configuration, like Tetrapod and Dolos. Later the industry shifted to a one-layer design where concrete use became less since fewer units were needed. The industry standard of one-layer gave rise to various new armour units, like Core-Loc and Xbloc. Up to the present, this industry is mainly studied from a technological perspective where the hydraulic capabilities and design formulae are extensively researched (so called 'hard factors'). However, some units became very commercially successful in terms of units placed but others did not. In this highly technological industry, no market research is done in order to study which factors led to commercial success. In this study, an effort is made to investigate which factors are responsible for becoming successful in this branch. To do so, the concept of technological dominance is linked to this industry. Technological dominance is a technology management concept wherein a market similar technologies are ‘battling’ for the allegiance of the market. Eventually, the market selects a particular design and becomes dominant. Over the years scholars identified factors that contribute to obtaining technological dominance and collected those in a framework. In this study, the framework by Van de Kaa et al. (2011) is chosen. This framework consists of 29 factors that influence the outcome of a technology battle. The methodological approach for this study is to select relevant factors regarding this industry by interviewing 4 key experts. The identified relevant factors are then carried into the next round of interviews, where a broader group of 14 experts were asked to rank these factors according to the Best Worst Method. The Best Worst Method (BWM) is a multi-criteria decision-making tool, designed by Rezaei (2015), where the decision-maker expresses their preference by making pairwise comparisons. This method gives more reliable weights and requires fewer pairwise comparisons in respect to other multi-criteria decision-making tools, like AHP. The results yielded by this method suggest that the factor ‘brand reputation and credibility' are among experts considered as the most important factor for technological dominance regarding this industry. Furthermore, ‘hydraulic stability’ is in this branch considered second most important for obtaining technological dominance. Also, factors like 'marketing communications' and having a large network of stakeholders are considered very important. Based on the results, there can be concluded that in this technological branch soft factors can be more important than hard factors. This implies that in order to be successful in this industry actors should focus more on building a reliable and well-known brand reputation. In this branch, actors have proved that a strong brand name can help to extend the commercial lifespan of an armour unit with expired patent and can help to speed up the adoption of new armour units.