Chevron Marks

Chevron marks are often left on a fracture surface as a result of a fracture process. Most usually, they occur as a result of running fractures, i.e., fractures which progress through the structure. Chevron marks are extremely helpful to the failure analyst. Chevrons point to where the crack came from, i.e., where the crack ultimately originated.

A clear set of chevron marks is shown in Photograph A. The chevrons in Photograph A point from right to left indicating the fracture origin for the portion of the crack is located to the left of Photograph A

Photograph A Chevrons pointing from right
 to left indicating the origin of the fracture
 lies to the left of Photograph A.

Chevrons, in the hardened zone (lower smooth fracture) of a turntable slewing bearing fracture are shown in Photograph B. The chevrons in the hardened bearing case clearly indicate (point) to the right. Therefore, this particular crack originated to the right in Photograph B.

Photograph B Chevrons in hardened case
 of a turntable bearing point to the right
 indicating a fracture origin to the right of
 Photograph B.