Finite-Element Parametric Study of Split Sleeve Cold Expansion Process

Luis A Brito-Santana

doi:10.7273/000005540

Owing to some manufacturing defects along with human errors during the split-sleeve cold expansion process (SSCE) may imply unwanted changes in residual stresses and consequently in fatigue life of metallic structures with holes, resulting in probable crack initiation. The objective of this study is to determine how manufacturing variables affect the fatigue life i.e., residual stress, contact pressure, strain, and pulling force of this process. In addition, a parametric study was conducted for the SSCE process. The geometrical modification of the hole, as well as the angular pulling of the mandrel and sleeve with respect to varying coefficient of friction, are investigated to observe how they influence the SSCE-induced residual stresses, mandrel pulling force, strain, and contact pressure exerted by the mandrel. Using commercial finite element (FE) software, ABAQUS, a 3-D FE model was generated to Investigate the effects of the aforementioned parameters. The entry and exit hole diameter are varied up to 90µm (0.09mm) along with a maximum angle of 1.5° perpendicular to the pulling direction for both mandrel and sleeve. Two different Coefficient of friction (0.05 and 0.1) was also considered for the analysis. The results of our research show that residual stress varies asymmetrically around the hole with a declining trend of circumferential compressive stress in the exit and entry face adjacent to the hole. It was also observed that contact pressure and pulling force changes substantially with increasing friction coefficient. The residual stress distribution is influenced by several factors. These factors are separated into two sections for a better understanding: manufacturing parameters and analytical parameters. Friction, mandrel design, split sleeve design, mandrel velocity, geometric configurations, expansion percentages, and material properties are some of the process parameters. Analysis parameters are decisions and assumptions made during the analysis to come as close to a realistic process as possible. This involves factors like choosing an analysis type, analyzing contact between assembled parts, setting boundary conditions, meshing methodologies, mesh sensitivity, mesh element quality, and interaction features, among other things.

Finite-Element Parametric Study of Split Sleeve Cold Expansion Process

Files and links (1)

Abstract

Metrics

Details