Continuous: Tube

Unlike a segmented pipe, a continuous tube has no axial stress discontinuity at joints, so no stress concentration factor ($K_t \approx 1$) in the longitudinal direction. This significantly improves burst strength and fatigue life. When a continuous tube is bent to a radius $R_b$, the bending strain is:

where $D$ = outer diameter. For coiling, the minimum bend radius without plastic collapse is: continuous tube

Bending strain: $\epsilon = \fracD2R_b = \frac25.42 \times 1200 = 0.01058$ (1.06%) Unlike a segmented pipe, a continuous tube has