Research On Mechanical Performance Analysis And Lightweight Design Of The Bending Stiffener Of The Marine Umbilical

Nowadays,with the growing demand for oil and gas resources,countries are paying more and more attention to the development and utilization of oil and gas resources.The oil and gas resources on land has been developed,and countries are putting the focus into the ocean.In deep water environment of the South China Sea,the oil and gas resources are extremely rich,but the immaturity of China’s underwater production technology has severely restricted the oilgas fields development progress of deep water in the South China Sea.The umbilical serves as the "lifeline" between the floating body and the underwater production system.Once damaged,it will cause immeasurable economic losses.In order to prevent damage to the umbilical,improve the service life of the umbilical,and break the technical barriers of underwater production technology,the design and research of the bending protection accessories is of extremely great academic value and important practical significance.Based on the 1500 water depth of the South China Sea,this paper takes the bending protection accessories of the marine umbilical as the research object,using finite element method as the main analysis method,and applying intelligent optimization algorithms and topology optimization to light-weight design of the bending protection accessories.The main research contents are as follows:According to the operating conditions of the bending protection accessories of the marine umbilical,the working principles of two kinds of the bending protection accessories are respectively elaborated.The local mechanical properties of the double-armored umbilical with central steel tube unit are compared and verified by theoretical methods and finite element methods.Determine the material selection and basic structural size parameters of the initial bending protection accessories.The overall analysis of the umbilical is carried out according to the marine environment of 1,500m water depth in the South China Sea,and the rain-flow counting method is used to extract the load conditions used for the subsequent analysis.A mechanical model of the bending protection accessories of the umbilical is established,and a theoretical method for the curvature analysis of the umbilical is proposed.The mechanical properties of the bending protection accessories are studied and analyzed,and the protection mechanism is further explained.Material nonlinearity analysis is introduced,and the results of material nonlinearity analysis are compared with those of neglected material nonlinearity analysis,and the effects of material nonlinearity and material temperature on the performance of the bending protection accessories are investigated to provide reference standards for structural optimization in the following textFor the lightweight design of the bend stiffener,the design variables are determined by analyzing the parameter sensitivity of different structural sizes,taking the lightweight and fatigue resistance of the bend.stiffener as the optimization objective.Based on the curvature theory analysis method,multi-objective structural optimization was carried out by intelligent optimization algorithm.The accuracy of various optimization algorithms is compared,and the optimal result is obtained.And using theoretical methods and finite element methods to verify the performance of the optimization results,to prove the feasibility of the optimization methodology.For the lightweight design of the bend restrictor,taking flexibility minimization as the optimization goal.Using OptiStruct software to carry out topology Optimization under the conditions of quality and strength constraints.And using curve fitting method to reconstruct the model to obtain the best results.The working performance of the optimization results is verified by the finite element method,and the physical scale model of the bend restrictor is processed by 3D printing technology to prove the feasibility and manufacturability of the structural optimization methodology.