NUMERICAL SIMULATION OF ELASTIC-PLASTIC DEFORMATION OF TORSION SHAFTS OF VEHICLE SPRING SYSTEMS, TAKING INTO ACCOUNT CONTACT INTERACTION

The paper develops a model of stress-strain state of torsion shafts. A variable formulation of the problem on the basis of the theory of variational inequalities was made. Numerical modeling of the stress-head-deformed state was made with the involvement of the finite element method. In the model of the stress-head-deformed state of torsion shafts, its generalized parametric description is integrated. It contains both varied significant design and technological indicators, in particular, the structural design of the torsion head, the galley transition and the diameter of the stem torsion shaft stem, and the parameters of the technological process of double winding: twist angles and features of the shaft material. It is established that the stresses that occur in the torsion shaft are mainly concentrated in the contact interaction zone of the spline shaft head with the spline coupling. The parametric dependencies of the level of equivalent stresses by Mises on the level of double windings and on the ratio of the head diameter and the stem of the torsion shaft stem have been determined. Recommendations have been developed regarding the improvement of strength characteristics of torsion shafts. Contact pressure distribution on the slots of the torsion bar head is also determined. Its characteristic features depend on the type of boundary conditions. If bilateral interaction is enabled on the boundary, the contact pressure may become negative. Furthermore, the contact pressure gets a sharp spike. This non-physical feature disappears if unilateral contact conditions are imposed. Therefore, this version of the boundary conditions is more adequate. It was used to compute the stress-strain state of a torsion bar, taking into account the plastic deformation of the material and the contact interaction with conjugate bodes.
Keywords: torsional shaft; stress-strain state; finite element method; theory of variational inequalities; contact interaction