RELIABILITY OPTIMIZATION DESIGN OF THE STEEL TUBE UMBILICAL CROSS SECTION BASED ON PARTICLE SWARM ALGORITHM

Umbilical is one of key control equipment in the under-sea production system. The cross section at the top of configuration could undertake the most dangerous load cases during operation. Firstly, the uncertainty of components in the section is investigated, and the strength failure is analyzed under this working condition. Based on above content the limit state equation is established. Then, the reliability of the umbilical is calculated by improved first order second moment method and Monte Carlo method. Finally, strength reliability optimization equation is established with the objective of minimum mass of unit length, which takes the external diameter and wall thickness of steel tubes as variables, with the consideration of the reliability constraint. The particle swarm optimization algorithm is adopted to solve the problem, the results of which show that reliability index is 67.43% higher than the original design. The effectivity of this method is verified, which is greatly engineering significant to guide the high-performance design of the umbilical.