Dataset underlying the MSc thesis: Development of an instrumented mooring system for VFFS model testing: Focused on the sensor configuration and calibration procedure

Floating structures have developed significantly in recent years. As land is becoming scarce, the use the water surface will contribute to ease this scarcity. Therefore in recent years, floating structures covering large areas have been developed, also called flexible floating structures. In this project the focus is set on the mooring system very flexible floating structures (VFFS). At the TU Delft, two towing tanks can be used to investigate the mooring system of VFFS, however first a reliable measuring system is required that is able to examine a specific part of the mooring system. Conventional setups that measure the mooring forces consist of large instruments, as these instruments only have a small effect on their investigated structure (vessels). The response of VFFS is dominated by elastic deformations and differs from conventional rigid structures. For VFFS, these type of instruments will have a large effect on the structure motions and thus these conventional setups cannot be used. Therefore, a new measuring system is required to conduct small scale experiments with VFFS, and the following objective is formulated: Develop an instrumented mooring system for VFFS at model scale for the towing tank at the TU Delft and determine its accuracy. A new concept is developed in this project. This concept resulted from an extensive concept development where all functions of the system were analyzed. With the use of a Morphological Chart and a Multi Criteria Analysis the best concept was selected. For this concept, it was determined that the focus should be on the sensor configuration and calibration procedure. First, the optimal sensor configuration of the concept was specified by analysing the working principle of the concept. Second, the calibration procedure was further analyzed. From this analysis, three calibration procedures were developed: the single sensor calibration matrix, the full fixed calibration matrix and the full rotated calibration matrix. From literature and theory, it was not possible to determine in advance what calibration procedure should be selected, and therefore the performance of the procedures were verified with experiments. All calibration procedures were executed, whereafter the performance of the different procedures were compared. The two main considerations for the comparison were the accuracy and the usability of the procedures. After performing the comparison, the main conclusion was that the full upright calibration procedure is the optimal procedure. To verify the concept under realistic conditions, an example application was performed in the towing tank No.1 at the TU Delft. By doing this, the concept has proven to be suitable to measure the mooring force and transform them into usable data. In this project a new concept was developed into a working system. This system forms an excellent base for extensive research into the mooring system of VFFS, and is a good addition to the measurement instruments for the towing tank at the TU Delft. It is concluded that the system is able to measure the mooring forces and the direction. The accuracy of the system still has to be improved, and with additional research the working concept can be further developed.

近年来，浮式结构技术取得了长足发展。随着陆地资源日趋紧缺，开发利用水面空间可有效缓解这一困境，因此近年出现了大跨度浮式结构，亦称柔性浮式结构。本项目的研究对象为超柔性浮式结构（Very Flexible Floating Structures，VFFS）的系泊系统。代尔夫特理工大学（TU Delft）拥有两座拖曳水池，可用于开展VFFS系泊系统的相关研究，但首先需要搭建一套可靠的测量系统，以实现对系泊系统特定部件的测试。传统的系泊力测量装置多采用大型传感器，这类传感器对被测船舶结构的干扰极小，但VFFS的运动响应以弹性变形为主，与传统刚性结构截然不同，若采用这类传统测量装置，其对VFFS的运动干扰将十分显著，因此无法适用于本项目的测试需求。因此，本项目需要研发一套适配VFFS缩尺模型试验的新型测量系统，据此确立如下研究目标：为代尔夫特理工大学拖曳水池搭建一套带传感功能的VFFS系泊系统，并对其测量精度进行标定。本项目研发了一套全新的测量方案，该方案源自对系统各项功能的全面分析所开展的大量概念设计工作，通过形态学图表法与多准则分析，最终选定了最优方案。针对该最优方案，研究重点聚焦于传感器配置与校准流程两大方面：首先，通过分析方案的工作原理，明确了该方案的最优传感器配置；其次，对校准流程展开深入研究，据此提出了三种校准方案：单传感器校准矩阵法、全固定校准矩阵法与全旋转校准矩阵法。仅通过文献与理论分析无法预先确定最优校准方案，因此需通过试验验证各方案的性能。本项目对三种校准方案均开展了试验，并对其性能进行了对比，对比的核心指标为测量精度与操作易用性。对比结果显示，全直立校准矩阵法为最优校准方案。为验证该方案在实际工况下的适用性，项目在代尔夫特理工大学1号拖曳水池开展了实例应用试验，试验结果证明，该方案可有效测量系泊力并将其转化为可用数据。本项目将全新研发的方案搭建为一套可实际运行的测量系统，该系统为VFFS系泊系统的深入研究提供了优质的试验平台，同时也为代尔夫特理工大学拖曳水池的测量工具库增添了有力的补充。综上，该系统可有效测量系泊力及其作用方向，但系统的测量精度仍有待提升，后续可通过进一步研究对该方案进行优化完善。