正反顺序加载下安装边螺栓预紧力分散度的数值模拟与试验验证

在航空发动机机匣安装边装配过程中，不同位置螺栓之间会产生弹性交互作用，不同加载方案会使装配后的螺栓预紧力存在一定的分散度。针对这一问题，建立了3层带止口机匣安装边3维接触有限元模型，研究不同加载方案下螺栓预紧力的施加方法。基于有限元模型数值模拟了3层机匣安装边分别在顺序加载方案、交叉加载方案和正反顺序2轮加载方案下螺栓预紧力的分散度。搭建了相应的试验装置，分别对3种加载方案的预紧力分散度进行试验验证。结果表明：采用正反顺序2轮加载后的螺栓预紧力分散度最小，在3层止口机匣安装边上采用正反顺序2轮加载方案后的螺栓预紧力分散度较小，在有限元仿真中螺栓预紧力分散度为2.43%，在试验中螺栓预紧力分散度为4.98%。采用此方案加载后，止口机匣安装边能达到更好的密封效果和较好的刚度对称性。

Numerical Simulation and Experimental Verification of Flange Joint Bolt Preload Uniformity Under Clockwise-counterclockwise Circular Tightening Sequence

In the assembly process of aeroengine casing flange joints, elastic interaction occurs between bolts at different positions, and different tightening sequence cause bolt preload dispersion to a certain extent after assembly. To solve this problem, a 3D contact finite element model of the 3-layer casing flange joint with a spigot was established, and the methods of applying the bolt preload under different loading schemes were studied. Based on the finite element model, the bolt preload dispersion of the clockwise tightening sequence, the cross tightening sequence, and the two-pass clockwise-counterclockwise circular tightening sequence for the 3-layer flange joint were simulated numerically. The corresponding test equipment was set up to verify the preload dispersion of the three loading schemes. The results show that the bolt preload uniformity is the best when adopting the two-pass clockwise-counterclockwise circular tightening sequence, and the bolt preload dispersion is relatively small. The bolt preload dispersion results from the finite element simulation and the test are 2.43% and 4.98% respectively. After adopting this loading scheme, a better sealing effect and stiffness symmetry can be achieved for the flange joint with a spigot.