Axial stiffness of a rotating trunnion joint

Abstract

A trunnion joint is modeled as a circular plate with two types of outer boundary conditions. One is clamped supported and the other is simply supported. Symmetrical bending deflection is produced when an external force acts on the inner side of the circular plate. The governing equations of the circular plate with these two kinds of boundary conditions are solved by using finite difference method, and the axial stiffness of the circular plate is obtained according to the relationship between the external force and the bending deflection of the circular plate. In order to verify the accuracy of the finite difference method, a finite element method was also given. The effects of rotational speed and the ratio of inner radius to outer radius of the circular plate on the axial stiffness are studied. It is shown that the rotational speed can significantly affect the axial stiffness of the trunnion joint for these two cases, especially for a lower ratio of inner radius to outer radius of the circular plate. The axial stiffness increases monotonically with the increase in rotational speed. More specifically, for a lower ratio of inner radius to outer radius of the circular plate, the axial stiffness with the simply supported boundary condition at high rotational speed is more than twice as much as the case without considering the rotational speed. Correspondingly, it is more than one and a half times for the clamped supported boundary condition.

A theoretical solution of the axial stiffness of a cylindrical shell with a circular plate

“…The trunnion joint is composed of a thin walled cylindrical shell on the leftmost side, a thin circular plate end cap, and a thin quill shaft on the rightmost end. 4 The sketch of the trunnion joint is shown in Figure 1. These three components can be seen clearly from the normal-sectional view of the trunnion joint shown in Figure 1(b).…”

“…For the first boundary condition, there should be no bending deflection of the circular plate at the outer peripheral sides, 4 thus …”

“…The second boundary condition requires the slope of the circular plate on the outer peripheral side should vanish. 4 It can be written as …”

“…Feng et al studied the effect of the rotating speed on the axial flexural rigidity of a trunnion joint, where the outer peripheral clamped or simply support boundary conditions is used to model the trunnion joint. 4 The axisymmetric large bending deflection of annular plates was calculated by using the Ritz method in Tielking’s paper. It was shown that the effect of large deflection on the axial stiffness becomes significantly.…”

Numerical and experimental investigation of the torsional stiffness of flexible disc couplings

“…Chakrabarti [8] used a modified test rig to study the torsional stiffness of flexible rubber couplings, as well as dynamic stiffness and the linearity ranges of the stiffness curves. Feng et al [9] calculated the axial stiffness of a trunnion joint and investigated the effects of rotation speed on its axial stiffness. Shentu et al [10] derived design equations based on a simplified model of laminated membrane coupling to calculate the torsional stiffness and axial stiffness.…”