The Scheme Design Of CALM Mooring Device And Analyze Of Mooring Ability For Extreme Sea Condition

Catenary anchor leg mooring device(CALM for short)is the earliest and most widely used SPM device.Because of its advantages,it is mainly used as the terminal of offshore oil unloading.It can not only cooperate with the traditional oil wharf,improving the efficiency of oil unloading operation,but can be used independently,unloading oil in areas not suitable for the wharf.In this paper,based on the design requirements of a CALM device,the key problems and methods of the scheme design and mooring analysis are carried out,while the reasonable scheme is proposed at the same time.In this paper,through the static analysis,establish the catenary equations.According to specification,the material selection of anchorage cable is completed,and four reasonable preliminary plans are put forward based on the results.Then,calculates the mooring force and stiffness curve of each plan by MATLAB software.Through statistical analysis,the expression of recurrence period environmental condition is established,and the environmental conditions of extreme sea conditions are calculated based on the observed samples.According to the connection mode between Mooring Ships and buoys,carries out the calculation steps of the "single floating body" and the "double floating body" system by the quasi static force method,and analysis the four preliminary schemes.Then,screens the schemes based on the results.AQWA software is used to simulate extreme sea conditions lasting three hours and calculate the wave load,buoy offset motion response,anchor cable tension response and mooring force response under different environmental directions.Comparing the results of dynamic method and quasi-static force method,analyzes the influence of assumptions on the results in quasi-static force method,and screen the final scheme.Based on the static analysis and catenary theory,the study of the mooring system of CALM device is carried out.The mooring ability under the extreme sea conditions is analyzed by using the quasi static force method and the dynamic method respectively.The research results have some reference significance for similar structures design.