Fig. 3

(a) Representative rotational angle–torque curves under the rotational test combined with compression force in each group. (b) Representative torque–maximum principal strain curves under the rotational test combined with compression force in each group. (c) Representative torque–minimum principal strain curves under the rotational test combined with compression force in each group. Both the rotational angle-torque curve and the torque-strain curves in the Square group showed two steps before complex failure