Measurements of strain fields around crack tips under proportional and non-proportional mixed-mode fatigue loading

For various configurations examined in a series of fatigue experiments on thin-walled tubes under tension and torsion, the experimental results – crack path, crack growth life, near crack tip deformations, and crack closure – are measured. Optical inspections and digital image correlation technique were used in the experimental investigation. Crack opening and closure loads were determined. The mechanical material behavior has been assumed as...