Coupling structure includes: a first and a second pipe section each having a metal wall and a flexible pipe section interconnecting the first and second sections, a hinging support frame including a first set of arms connected to the first pipe section, a support ring around the flexible pipe section hingingly attached to the first set of arms, the first set of arms being pivotable around a first axis, and a second set of arms connected to the second pipe section and hingingly attached to the support ring, the second set of arms being pivotable around a second axis transverse to the first axis, the base ends of the first and second set of arms are connected to the first and second pipe sections via at least one connector member extending transversely to the respective pipe section, at a predetermined distance from the pipe section metal wall, the arms extending along the respective pipe sections over a predetermined length such that a gap between the pipe section metal wall and the arm is defined over the length.