自紧影响CNG-2气瓶疲劳寿命的主因探究

Main Causes of Autofrettage Effect on Fatigue Life of CNG-2 Gas Cylinder

利用有限元数值分析,根据欧标EN13445-3-2009相关规定,对自紧影响气瓶疲劳性能的原因和规律进行研究。结果表明:随着自紧压力的增加,气瓶内胆工作压力下拉应力降低,但零压下压应力增加,使得内胆的应力幅基本保持不变,而平均应力降低。另外,依据EN13445-3-2009相关理论,得出应力幅不是自紧改善气瓶疲劳性能的主要原因,平均应力降低才是影响疲劳寿命主因的结论。

Through having FEM numerical analysis adopted and EN13445-3-2009 codes based, both reason and rules of autofrettage effect on the fatigue performance of CNG-2 cylinder was investigated to show that, with the increasing of autofrettage pressure, the steel liner＇ s tensile stress under working pressure can become decreased while compressive stress under zero pressure increases, and this can keep the stress amplitude con-stant while the average stress decreases. According to EN13445-3-2009 codes, the conclusion that the stress amplitude is not the main reason of autofrettage improving the fatigue performance and the average stress＇ re- duction mainly influences the fatigue life was reached.