Study on the behavior of sunk screw connection between cabins in the rocket

A finite element model is conducted to investigate the behavior of sunk screw connection between cabins in the rocket. The finite element model is compared with experiment by the displacement along cabin. The load distribution of sunk screw connection between cabins subjected to bending moment and axial force is studied by analytical approach and numerical approach. It is found that the analytical approach can predict the load distribution accurately when the connection subjected to bending moment only and the friction is ignored at the same time. The axial force has significant effect on load distribution. With the rise of axial force, the shear forces on screw-1 to screw-3 significantly increase and the shear forces on screw-11 to screw-13 significantly decrease. Then a qualitative parametric study is presented to investigate the influence of friction and pretension on load distribution and strength. It is shown that with the increase of friction coefficient, the shear forces on sunk screw and the slope of shear force curve decrease. Therefore, the average attenuation coefficient can be introduced to predict the load distribution more accurately. In addition, the shear forces on screws reduce approximately linearly with the rise of pretension and the optimum pretension force can be predicted by finite element method.