Finite Element Modeling And Analysis Of Three-stranded Wire Helical Spring Based On ANSYS

Three-stranded wire helical spring is rolled by steel strand,which is composed of three carbon steel wire of 0.4~3mm in radius.The spring has the characteristics of strong rigidity,good effect of absorbing vibration and long fatigue life compared with common spring.Hence.It has important applications in the fields of aerospace and automatic weapons.Three-stranded wire helical spring is complicated in structure.The friction between the steel wires and the deformation at the contact area make it difficult to reflect the real situation of the spring after suffering force by using theoretical analysis.So it is very necessary to analyze it by finite element method.The analysis model of spring can be simplified by using helical symmetry boundary conditions thanks to its helical symmetry in geometric structure.In this paper,the space forming process of the three-stranded wire helical spring is introduced.Vector projection method is used to derive the mathematical equations of centerline of the steel wires.Then,three-dimensional parametric finite element model of the three-stranded wire helical spring is established by using APDL language in finite element software ANSYS.The mechanical properties of the static axial loading process are simulated by applying accurate helical symmetrical boundary conditions between the cross sections of both ends and the relationship between the axial force and the axial tensile strain are obtained,including the stress distribution.The influence of the geometrical parameters on the performance of the three-stranded wire helical spring is studied by using the developed finite element model.It is found that the spring stiffness and the equivalent stress in the cross section increase with the increase of the spiral angle,decrease with the increase of the spring index,and increase with the increase of the cable angle.The results of two cases of friction and no friction are compared.The results show that the relative displacement between spring steel wire decreases and the equivalent stress of the local contact increases due to friction.