Analysis of residual stresses around welds in a combustion casing

The electron-beam (EB) welding process and the subsequent post-weld heat treatment (PWHT) in an aero-engine combustion casing were simulated in 2D and validated by comparison with hole-drilling measurements. The full 3D modelling including the details of the complex component geometry was then carried out, and used as the “reference” state for the eigenstrain reconstruction problem. Permanent strain distribution along two hoop welds and a circumferential soleplate weld were represented using a set of basis functions appropriately chosen and justified for the specific case considered. Inverse eigenstrain method was applied in order to determine the unknown parameters that give rise to the best agreement between eigenstrain reconstruction and the “reference” residual stress (RS) distributions. The result appears to capture successfully the RS distribution at all locations of major stress concentration, and to provide a satisfactory RS approximation in other regions.