Modified Symmetry Cell Approach for Simulation of Surface Enhancement Over Large Scale Structures

Author:  T. Spradlin, R. Grandhi and K. Langer
Source:  Conf Proc 2011: ICSP-11 South Bend, IN USA (pgs. 111-116)
Doc ID:  2011018
Year of Publication:  2011
Abstract:  
Abstract Physical surface enhancement techniques such as Shot Peening (SP), Laser Peening (LP), and Low Plasticity Burnishing (LPB) offer excellent fatigue mitigation options for the design engineer due to the compressive surface stresses they imbue. These techniques must typically be used on large surfaces to garner any type of advantage. To understand how these large-scale residual stress fields affect the fatigue life of a structure, the LP residual stress field must be in place on the simulated structure so that its effects on loading can be observed. A highly refined mesh is required to obtain a reasonably accurate residual stress field. This mesh refinement combined with any type of plasticity equates to a long simulation time. For processes that rely on a large number of simulations, i.e., each shot of an SP or LP pattern, this translates to a time-prohibitive simulation. By carefully constructing the simulated peening area outside the boundaries of the region of interest, an accurate symmetry cell is created in an AISI 1045 steel. The symmetry cell constructed within this work is then compared with previous symmetry cell methods and experimental data to demonstrate improvement in accuracy. Keywords Symmetry Cell, Laser Peening, AISI 1045 Steel, FEA.