A Theoretical Model for Characterizing the Internal Contact of the CICC Strands under Axial Strain

A theoretical model is proposed to calculate the internal contact distributions and contact forces of a 3×4×4×4 twisted Nb3Sn cable under applied axial strain. The critical current density reduction of the whole cable can be calculated. The thin rod theory is employed to analyze the mechanical behavior of each strand. According to the regular helical structure, the contact distribution of each strand is obtained, and the contact force in the cable is analyzed. At last, a prediction about the critical current density of the twisted cable is made. The results show that decreasing the pitch length can reduce the contact forces between strands.