带扳手槽舱段轴向对接结构弯曲刚度的半解析分析

Connecting stiffness is a significant factor that must be considered in studying the structural dynamic characteristics of missiles.Currently,the structures of small and medium-sized projectiles mostly adopt the axial connecting structure with slot-nuts. Due to complex geometric shape and multiple design parameters,it is hard to obtain an analytical expression for the connecting bending stiffness.Based on the theory of elastic bending deformation beam,a semi-analytical analysis method for the bending stiffness of axial connecting structure between cabins with slot-nuts was proposed.The calculation method for the neutral axis was determined, and the theoretical formula for connecting bending stiffness was derived.Based on the circumferential cyclic symmetry of the connecting structure,a parameterized model of the 1/ n connecting substructure was established,and a method for determining the axial calculation length was provided.The tensile and compressive stiffness of the substructure was obtained using nonlinear contact analysis method.The obtained tensile and compressive stiffness were substituted into the theoretical formula to obtain the connecting bending stiffness.Finally,the influence of the main design parameters on the bending stiffness was researched through orthogonal experiment. The results show that the maximum relative error between the bending stiffness obtained from semi-analytical calculation and the finite element calculation of the overall structure is -13.86% and the minimum is -3.337%.In the theoretical calculation of bending stiffness,the position of the bending neutral axis should be reasonably calculated based on the actual tensile and compressive stiffness. When the diameter (≤300 mm) of the cabin is constant,the influence of connection thickness on bending stiffness is most significant, followed by the stud number.Relatively speaking,the influence of stud specifications and preload level is relatively smaller.