Finite element analysis of copper–Nb3Sn contact performance under transverse compression

• To build the 2D model of Nb3Sn strand and analyze the copper strand influence on contact strain state with flat and concave plates.
• The two strand contact forms are (a) Nb3Sn–Nb3Sn contact model and (b) copper–Nb3Sn contact model (the cooper on the top).
• The three strand contact forms are (a) Nb3Sn–Nb3Sn–Nb3Sn contact model and (b) copper–Nb3Sn–Nb3Sn contact model (the cooper on the top).
• The average von-Mises strain of bottom Nb3Sn in two strand or three strand contact forms (a) and (b) with flat or concave plates is the same.
• The copper on the top press construction has no more influence on the strain distribution in Nb3Sn strand under the transverse compression.

It turns out from recent researches on Nb3Sn conductor that contact strain is important for Nb3Sn conductor, as it could cause the degradation of the conductor itself. Few experimental results describing the behavior of Nb3Sn sub cables under transverse load are available. Numerical modeling is one method to investigate the contact strain inside the cable. In this paper, finite element method was used to analyze the two- and three strand contact strains under two pressing configurations: flat and concave plates. From the finite element analysis, it is found that the average von-Mises strain of bottom Nb3Sn in Nb3Sn–Nb3Sn–Nb3Sn contact model and copper–Nb3Sn–Nb3Sn contact model is the same under flat or concave plates; the average von-Mises strain of bottom Nb3Sn in two strand contact model is also the same. It is also verified that the shape of the top copper press has no more influence on the strain distribution in Nb3Sn strand under the transverse compression.