The dynamic load responses are often concern in floatover system analysis. In this paper, experimental research on the mating process of the floatover system is conducted to analyze the dynamic load characteristics of LMUs (Leg Mating Units) and DSUs (Deck Support Units). The experimental model applies a dynamic ballasting system and carefully designed LMU and DSU. The continuous mating models are tested to investigate the dynamic load characteristics and the critical load transfer interval, and the critical stationary stages are further analyzed. The results find that the PSDs of LMU forces have similar shape and distribution, and the pitch motion of vessel contributes the most to forces.
Installing an offshore platform topside is an important and high-risk activity in ocean engineering. The widely applied deck installation methods mainly consist of lifting methods by using crane vessels and floatover installation methods. With the development of offshore platforms towards large-scale trends, the lifting method usually takes long hook-up, commissioning, and offshore installation durations, and the capacity and availability of the crane vessels are also limited (ONeill et al., 2000). In addition, the increase in offshore wind turbines in the future will also lead to increased demand for the installation of large offshore converter stations, and a fast and safe installation method is needed to complete it. Compared with the lifting method, the floatover installation method has the advantages of higher capacity, higher efficiency, and lower costs, which becomes more popular in large integrated topside installations (Tian et al., 2018).
Floatover operation generally consists of transportation, docking, mating, and undocking processes. In these processes, the mating stage has always been widely concerned and investigated because of the inherent complexity of multi-body coupled and nonstationary dynamics. During the mating stage the stabbing cones of the topside will gradually contact the receptors of LMUs to transfer the deck weight with the floatover vessel ballasting, as shown in Fig. 1. The LMUs and DSUs will absorb the impact loads of the floatover system, which is worth investigating.
