Finite Element Analysis of Coiled Tubing Fatigue Life under Different Internal Pressure

In order to make up the theoretical calculation defect on accurately predicting the fatigue life of coiled tubing, ANSYS Workbench finite element analysis software is used to establish the three-dimensional finite element mechanical model of coiled tubing at working condition. The finite element analysis steps of coiled tubing fatigue life is attained to analyze the fatigue life of coiled tubing under different internal pressures and investigate the influence of wall thickness on the fatigue life of coiled tubing, and the analysis result was compared with the experimental results obtained by the previous paper. The results of the investigation show that, the calculated results have the same trend as the experimental results of the coiled tubing with different wall thickness and under different internal pressure. The maximum error is less than 8.46% and the average error is 5.84%~7.04%, which can meet the requirement of engineering precision, verifying that finite element method could be used for coiled tubing fatigue life analysis. The increase of the wall thickness can not only increase the strength of the coiled tubing but also prolong its fatigue life.