Open AccessPredictive Crack Growth Technique for Laser Peening Process Development
Author(s) -
Spradlin Thomas J.,
Hodges Joshua L.
Publication year - 2015
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2015.0110
Subject(s) - laser peening , residual stress , shot peening , materials science , ultimate tensile strength , peening , residual , structural engineering , paris' law , crack closure , fracture mechanics , composite material , computer science , engineering , algorithm
Laser peening (LP) has shown excellent fatigue life extension in numerous tests with typical treatments garnering 2‐4 times the fatigue performance of an untreated component. Initially, large test programs were implemented to determine the best LP parameters for a given scenario, eventually being augmented by physics‐based modeling due to the large design space available to the LP process. Approval for these processes continues to be on a case‐by‐case basis, contingent on multiple factors: cost, applicability, time, % fatigue life extension, and ability to track crack growth. Because LP induces compressive residual stresses in the near surface region, the compensatory tensile residual stresses are shifted sub‐surface. While an axial tensile load would be mitigated by surface compressive stresses, sub‐surface a crack can propagate rapidly via tensile stresses. Current predictive methods lack the ability to track this sub‐surface behavior, limiting the accuracy of fatigue crack growth predictions throughout the various design stages of an LP treatment. This work demonstrates a framework that incorporates user‐defined geometry, material data, crack growth data, mechanical loading, and residual stresses to predict the crack front shape evolution in 3D solids. A baseline case with no residual stresses is simulated and compared with a closed form solution.