Effects of Elastic Anisotropy on Residual Stress Measurements Performed Using the Hole-Drilling Technique

Joshua T. Ward, Wright State University


In the present work, the variation in through-thickness residual stress profiles driven by elastic anisotropy is investigated using the incremental hole-drilling method. The standardized hole-drilling technique allows for the calculation of in-plane stresses based on measured surface strains, however, these calculations assume elastic isotropy. The assumption of elastic isotropy allows for the material constants to be reduced down to two values, however, this assumption is invalid for many materials used in aerospace design. These materials are often times elastically anisotropic, which leads to inaccuracy and uncertainty in measured stress profiles. An interference fit ring and plug sample was designed, using a finite element model, to impart a predictable stress profile for C260 brass with varying levels of crystallographic texture. Utilizing the finite element model, simulated and experimental hole-drilling measurements can be compared. The correlation study between the virtual and experimental stress profiles aids in quantifying the magnitude of errors caused by assumption of elastic isotropy. Understanding the potential sources of the errors will allow us to develop new modeling and experimental approaches that can incorporate elastic anisotropy into residual stress hole-drilling measurements.