Study of finite element analysis on tube fittings

Abstract

Abstract This study uses finite element analysis based on DEFORM-2D commercial software to explore the plastic behaviors in grip and seal of tube fittings. The tube fittings consist of tube, nut, front ferrule, back ferrule and body. The material of the tube is SUS 304 stainless steel, and the material of the tube fittings is all SUS 316 stainless steel. As the nut tightens, the back ferrule squeezes into the front ferrule while forcing the front ferrule into both the nut and the tube, which results in an effective mechanical grip and seal. The nut locking force changes with the geometry conditions of α, β, and γ in the back ferrule and the front ferrule. The results show that the nut locking force increases with the increase of the frictional factor, the back ferrule chamfer (β), and the front ferrule tilt angle (γ), however decreases with the increase of the front chamfer (α).