Product Code: ICAL09_205

Laser-Generated Crack-Like Features for Fatigue Testing
Authors:
Elizabeth Gounaris, Connecticut Center for Advanced Technology; East Hartford CT USA
D. Cassioppo, -; -
Paul Denney, Connecticut Center for Advanced Technology; East Hartford CT USA
Presented at ICALEO 2009

For several industries including aerospace, maritime, automotive and medical it is essential to develop a cost-effective, highly-reliable method to certify damage tolerances for fatigue-critical components. To certify materials for damage tolerances, they must have precise and repeatable artificial crack initiation sites in order to accurately measure fatigue deficits. At present, accepted methods of generating these crack initiation defects are by mechanical notching or Electrical Discharge Machining (EDM). Shortcomings of these methods include additional stresses applied to the material, lack of confidence of defect shape and size and the methods themselves are costly and time consuming. The Laser Applications Laboratory at the Connecticut Center for Advanced Technology (CCAT) has demonstrated through efforts with aerospace manufacturers that low powered lasers can be used as an effective method to create Laser-Generated Crack-Like Features (LGCLF) in selected aerospace materials and components. Using lasers to create LGCLFs has proven to be a less expensive, quicker, more repeatable and more flexible approach. As a calibration of the LGCLFs a fracture technique using liquid nitrogen was developed for visual evaluation as an alternative to traditional metallographic sectioning and polishing techniques. A review of potential future efforts and applications is also discussed.