Numerical Study on Stress Distribution of Double-Layered Split Ultrahigh Pressure Die

To obtain lower stress level for the first layer supporting ring, two types of double-layered split ultrahigh pressure dies with a conventional round cylinder and a novel quadrate cylinder were designed. The stress distributions of cylinders and divided supporting rings (DSR-RC and DSR-QC) were investigated by FEM. The results show that the cylinders of two types of dies have almost the same von Mises stress remarkably smaller than that of the Belt-type die. DSR-RC has high stress level on the inner wall and large stress gradient in the radial direction. Stress concentration appears between the divided plane and inner wall of DSR-QC. Four types of structure improvements with variable interference fit for the inner wall were performed to reduce the stress concentration. It shows that the stress concentration of DSR-QC can be significantly improved simultaneously with lower stress level than DSR-RC obtained. Compared with DSR-RC, the modified DSR-QC can reduce the von Mises stress by 18.2%. The numerical results were validated by destructive experiments. This work will be rewarding to improve the pressure performance and service life of split-Belt high pressure die.