Structure Design Of Underwater Pipeline Repair Machine And Modeling&Simulation Of Milling And Cutting Process

Underwater pipeline repair equipment, especially cutting machineSingle function, lowreliability and low Operating depth are common performance deficiencies of underwaterpipeline repair machine of our contry. With the support of “major projects for science andtechnology in developing great oil&gas field and coal bed gas”, the paper carries outresearches on Underwater Pipeline Repair Machine (UPRM). The main research contents ofthe paper include:The general structure project of UPRM is designed. On the base of the present state ofthe domestic and foreign research and the idea of modular design, UPRM is divided into fivemodules, include overall framework, pipeline operation mechanism, clamping mechanism,hydraulic circuit and buoyant equilibrium mechanism. The paper designes the structureproject of each module, establishes the3-dimensional model of UPRM, introduces operationfunction and principal of UPRM.Mathmatical model of progress of milling and cutting is founded. According to theoperation principle of UPRM, the primary motions are established. On the base of theprinciple of turn-milling mathmatical model of milling and cutting of UPRM is founded todescribe dynamic behavior of cutting tools of cutterhead. The ideal kinematic vector equationof one cutting edge of milling cutter, the eccentric kinematic vector equation of one cuttingedge of milling cutter and the kinematic vector equation of several cutting edges of millingcutter are deduced. On the base of that dynamic equations of milling thickness and depth arededuced, calculation methods of incidence angle and emergence angle are optimized and theempirical cutting force equation, the instantaneous dynamic cutting force equation of onecutting edge of milling cutter, the numerical and vectorial resultant cutting force equations ofmilling cutter in one cycle and power equation of milling and cutting operation are deduced.The progress of milling and cutting operation is simulated and process parameters areoptimized. According to the kinematic vector equation of cutting edges of milling cutter, theinfluence of each parameter of the equation on the orbit of cutting edges and the position ofthe orbit of cutting edges in relation to pipeline are researched in Pro/E. On the base of theprinciple of optimality, optimality mathmatical model of process of milling and cutting isfounded. Process parameteres are optimized under the constraint condition which is set up bytool life and milling parameters. According to the cutting force equation of cutting edges ofmilling cutter, the variation laws of the instantaneous dynamic cutting force of one cutting edge of milling cutter, the numerical and vectorial resultant cutting force of milling cutter inone cycle are researched in Matlab to get extremums, typical values and various cycles.Static characteristics and mode of milling cutter are analyzed. It is the worst workingcondition with maximum numerical resultant cutting force, then stress distribution anddisplacement deformation of milling cutter is researched to test strength and stiffness.According to actual working conditions, mode of milling cutter is analyzed in Abaqus to getfirst eight natural frequencies and mode of vibration. Milling cutter’s drive frequency issolved and compared with its first eight natural frequencies to analyze whether Resonancewould occur.