Research Summaries

Back Field-Based Residual Stress Measurements for Predicting Stress Corrosion Cracking

Fiscal Year 2013
Division Graduate School of Engineering & Applied Science
Department Mechanical & Aerospace Engineering
Investigator(s) Brewer, Luke N.
Sponsor Office of the Secretary of Defense (DoD)
Summary This program will employ portable XRD as a practical means for measuring the residual stresses in aluminum shipboard structures. Stresses in ship structures can lead to both stress corrosion and fatigue cracking. These stresses stem from residual stresses due to manufacturing processes, from unaccounted shifts in ship loading over time, and from repair processes such as welding. Peening processes such, as ultrasonic impact treatment (UIT), can be used to suppress stress corrosion and fatigue cracking by imposing a compressive stress into the near-surface region of the material. Despite its importance, we are not currently measuring the residual stress state at key locations on naval vessels. This information is required for predicting the appearance of cracks before they occur and for understanding the effectiveness of mitigation approaches such as UIT. For FY2013, this proposed program will consist of three activities: 1) receipt, installation, and testing of a portable x-ray diffractometer at the Naval Postgraduate School (NPS), 2) initial application of this approach to ultrasonically-treated areas on an actual naval vessel, and 3) comparison of laboratory and field-measurements of residual stresses at welds with and without UIT. This proposal represents a continuation of research for the Technical Corrosion Collaboration (TCC) for FY2012, which funded a feasibility study and the successful procurement of a portable x-ray diffractometer.
Keywords
Publications Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal
Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal