The reinforced S-shaped bellows, which can withstand high internal pressure, is a kind of typical metal bellows in aerospace and nuclear industries. Bending deformation is a typical displacement compensation of the reinforced S-shaped bellows. The discussion on bending characteristics of bellows under internal pressure has strong background of engineering application. In the present study, theoretical and numerical simulation analysis methods were introduced to investigate the bending characteristics of reinforced S-shaped bellows under internal pressure. Three different mechanical behavior characteristics were found in the whole bending process, they are high-rigidity, low-rigidity and rigidity sharply increase states. The state transition is mainly related to material nonlinearity and fitting relationship between bellows and reinforced hoop. Bending moment increases with the increase of internal pressure at the same angel of rotation, while both yield and sharply increase points forward. Although internal pressure makes the bellows yield earlier, the overall structure can still maintain a high displacement compensation capacity.

增强的S型波纹管可以承受较高的内部压力，是航空航天和核工业中的一种典型金属波纹管。弯曲变形是增强型S形波纹管的典型位移补偿。关于波纹管在内部压力下的弯曲特性的讨论具有很强的工程应用背景。在本研究中，介绍了理论和数值模拟分析方法，以研究内压力下钢筋S型波纹管的弯曲特性。在整个弯曲过程中发现了三种不同的力学行为特征，即高刚性，低刚性和刚性急剧增加的状态。状态转变主要与材料的非线性以及波纹管和加强箍之间的配合关系有关。在相同的旋转角度下，弯矩随内部压力的增加而增加，而屈服点和急剧增加的点都向前。尽管内部压力使波纹管更早屈服，但整体结构仍可保持较高的位移补偿能力。