Critical Constraints

• These wavelike bands radiate from the fracture origin.
• Wallner lines are created by interaction of the propagating crack front with a transverse elastic impulse, causing a momentary deviation of the crack front.
• May be observed without magnification.

Notes

• Not typically observed with filled materials.
• Useful in pinpointing initial fracture site.

If an initial fracture site and the suspect area that is believed responsible for the initial failure, have been located then you should consider modifying the design.

If the checklist has been followed and the initial fracture site has not been located, then you should contact an Eastman representative in your area for assistance.