threadstripping
Threadstripping is a failure mode in threaded fastener assemblies where the engagement between male and female threads is damaged or worn to the point that it can no longer carry load. This results in a significant loss of clamping force and may allow a fastener to loosen or withdraw under service stresses. Threadstripping can occur with external threads (bolts, screws) or internal threads (nut, tapped hole) and is often more about the thread profile being compromised than the nut or bolt breaking.
Common causes include overtightening beyond the material’s shear strength, cross-threading during installation, prolonged vibration, corrosion, wear
Detection symptoms are reduced torque resistance, the fastener spinning without drawing in, visible flattening or galling