The Design Of Subsea Demountable Modularized Diamond Wire Saw And The Study Of Parameter Optimization

In the field of offshore oil-gas production,for one thing,the nearshore oil-gas exploitation features long history,mature technology and gloomy prospect compared with deep sea peer,and for another,higher demands for emergency maintenance equipment are raised due to foreseeable ageing and various leakages.With late start and a weak basis,our core technology and fundamental research of subsea maintenance equipment lag behind major powers worldwide and have to be resolved.As step one of pipeline maintenance,underwater diamond wire saws designed for deep sea pipeline cutting is rather important.The conceptual design for emergency and the research on mechanism of cutting and wear are of great significance for securing the subsea oil-gas production.Subsea demountable modularized diamond wire saw was designed to realize resumption of production after wires breaking or overwearing and supporting work procedures are provided;The impact force of docking system was analyzed to optimize cone angles using ADAMS;Optimal Kalman Filter was chosen to control the feed of diamond wire saws and the process was simulated by simulation software.The results proved that Kalman Filter made the control of depth of feed and cutting speed more accurate and improved the immunity of the cutting process.After studying mechanism of diamond grits cutting,the cutting force model of single diamond grit was established using response surface method and design of experiments.Validated by VIF and ANOVA,the model reveals the influence of cutting speed,depth of cut and coefficient of friction on cutting force.Experiments using tribometer were conducted to compare cutting force results of the obtained model with real cutting,previous FEA&empirical model,causes of the difference were discussed behind.The RSM model proved to be more accurate,error-reduction-friendly and convenient for influencing factor analysis.After studying mechanism of diamond grits abrasion,the prediction model of wearing rate of single diamond grit was established by making results of the virtual experiments using smoothed particle hydrodynamics implemented with ABAQUS fit Archard formula.The model went through goodness of fit utilizing universal global optimization and reveals he influence of cutting speed,depth of cut and coefficient of friction on abrasion of diamond grit.To maximize cutting force models and minimize wearing rate models,multi-object evolution algorithm was adopted to gain pareto front.The optimal single diamond grit cutting could be achieved when the cutting speed is 17 m/s and the depth of cut lie between 29 μm and 33 μm.On the basis of data obtained from 3D Optical Profiler observing and measuring diamond beads,the surface topography of diamond beads was characterized and digitalized,which effectively connect abrasion of grits to wear of diamond beads.The micro to macro model proved to be a reliable method to deduce the variation of outer diameters by experiments conducted.