Stress of a Trunnion Joint

A trunnion joint is modeled as a circular plate with a rotational spring at the outer peripheral portion to resist rotation. Asymmetrical bending deflection is produced when an external moment acts on the inner side of the circular plate. The equations of the circular plate with a special outer peripheral boundary condition are derived. Choosing the stiffness of the rotational spring and the ratio of the outer radius and inner radius of the circular plate as two parameters, the stresses consist of the radial stress, hoop stress and tangential stress are calculated. The effect of the stiffness of the rotational spring on the radial stress and hoop stress becomes obvious for a greater ratio of the outer radius and inner radius. However, the tangential stress is independent of the stiffness of the rotational spring.