Evaluation of Mechanical Properties of Tubular Materials With Hydraulic Bulge Test for Superconducting Radio Frequency (SRF) Cavities

The plastic constitutive equation of tubular materials under hydraulic pressure needs to be determined for the successful application of hydroforming technique to the seamless fabrication of multicell superconducting radiofrequency cavities. This paper provides the empirical constitutive properties of tubular material determined by tensile and hydraulic bulge tests. During an experimental bulge test, the internal pressure, bulge height and wall thickness were continuously measured. Based on this data, the flow stress curves were calculated using an analytical model. From the obtained flow stress curves, numerical simulations were performed, and the resulting bulge heights and wall thicknesses obtained were compared with the experimental results to verify the procedure.