Fatigue Failure Due to Improper Design

There was a fracture of an anchor link that rides on a post with a spherical surface. No bevel or radius was called for, leaving an extremely sharp edge. A fatigue crack grew from the top sharp edge. The casting had good toughness and strength (1448 MPa, or 210 ksi, tensile strength). This fatigue failure was the result of poor design, which incorporated a notch that acted as a stress raiser, leading to fatigue-crack growth. A generous radius was recommended to avoid similar failures.