Finite Element Simulation of Residual Stress around Split Sleeve Cold Expanded Hole for AA7075

Abstract

Split sleeve hole cold extrusion strengthening technology is one of the most commonly used fatigue resistance technology for metal structures. The residual stress field of the hole cold extrusion strengthening structure needs to be analysed, which is an important part of the fatigue life study. Finite element analysis for the 7075 aluminum alloy cold extrusion strengthening plate is carried out in this paper. The effects of split sleeve and reaming process are considered in the analysis process, and the residual stress field at the hole edge is obtained. The numerical results are verified by the experimental results, which show that the two are in good agreement. It is show that the residual stress is the compressive stress near the extrusion hole while the tensile stress far away from the extrusion hole. Additionally, the compressive stress value is the largest in the middle layer, the smallest in the squeeze layer, and the value in the extrude layer is between the two.

Finite Element Analysis of Split Sleeve Cold Expansion Process on Multiple Hole Aluminum Alloy

“…A three-dimensional (3D) finite element model was developed for studying the split sleeve expansion process [ 23 ]. Zhang et al established a three-dimensional finite element model to simulate the SSCE process considering non-uniform stress distribution of the split sleeve, and found that the compressive stress value is the largest in the middle layer, the smallest in the squeeze layer, and the value in the extrude layer is between the two [ 24 ]. Based on numerical simulation and experimental testing methods, Seifi et al studied the effect of CE-induced residual stress of two adjacent holes on fatigue life and crack initiation period and analyzed the effect of expansion ratio and distance between adjacent holes on total life and crack growth life [ 25 , 26 ].…”

Numerical investigation of the effect of hole reaming on fatigue life by cold expansion

“…D r a f t field (Yang et al 2010;Zhu 2020;Zhang et al 2015). Cold expansion process with split sleeve can greatly reduce the damage of the hole wall, prolong the service life of the mandrel while ensuring the high interference amount of expansion, and improve the hole strengthening effect (Zhang et al 2019;Du et al 2018). It is well known that a reasonable reaming depth can not only ensure the assembly of bolts and nuts, but also remove large strains or small cracks at the ridges after cold expansion.…”

“…To obtain a convergent solution, the different mesh models are calculated. When the calculated maximum value difference between the two models is less than 1%, it is considered that the mesh size at this time meets the requirements of calculation accuracy (Zhang et al 2019). The different number of elements was set on the plate for grouping analysis, as shown in Table 3.…”