# Torsion of a tube through a kinematically coupled reference point

A tube a = 8, b = 10, L = 40 (four hex20 blocks around, 4 × 8 × 8 each) clamped at z = 0; its end
face is coupled kinematically to a reference point on the axis, which carries a moment
T = 10⁶ about z (E = 200000, ν = 0.3).