Analysis Of Longitudinal Buffering System Of Spud Carriage On Cutter Suction Dredger

With the development of dredging engineering, cutter suctiondredging is facing an adverse working environment. Its working field isextending from river to sea, and rock dredging is becoming more popular.As important dredging machines, large cutter suction dredgers haveupsizing installed powers, to meet the growing dredging demand. However,spuds of large cutter suction dredgers are prone to fatigue failure, bearingcomplex forces and extreme wave loads in adverse sea conditions, whichmake it a one of the factors limiting dredgers· production capacity. Soreducing forces on the spud and guaranteeing its reliability have been aproblem to be solved.In this study, the longitudinal buffer system of the spud-carriage (alsoknown as flexible spud system) build a connection between spud anddredger with crossed ropes, which is helpful in reducing longitudinal wavemoments. In this way, this buffer system is a guarantee for large cuttersuction dredgers to work in adverse sea conditions. In order to analyze how the system works and find out the basic designprincipals, the environmental loads and hydrodynamic coefficients of thedredger hull were obtained from HYDROSTAR. On this basis, a dynamicsimulation in time domain is done through AMESim, taking couplingbetween the system and ship motion into full consideration, to obtain thesystem·sdynamiccharacteristics.Inthesimulation,someparametersofthehydraulic control loop were altered to discuss the sensitivity of the buffersystem to them, including numbers of accumulators, preloading, diameterof the wire rope, the length distribution, taper of the damping valve core,diameter of the damping hole and the spring stiffness. The analysisconclusion showed that these parameters could change the stiffness of thesystem, which is measured by magnitude of load under unit rotation. Hencethe system could reduce its stiffness to improve its buffering efficiencywith less positioning accuracy for sacrifice.In conclusion, the quantitative analysis reveals the design basis of thebuffer system, laying a foundation to further improve dredger·s sea-keeping performance.