WASHER
DTIs are a function of induced tension. As a fastener assembly is tightened, the arch-like protrusions are compressed and the change in distance between the base of the protrusions of the DTI washer and the protrusion apex, correlates to a value of tensile force induced into the fastener. This distance can be verified by insertion of a tapered feeler gage between the protrusions to the bolt shank. The number of instances the bolt shank can be reached by the feeler gage is then compared to either the results of a pre-installation verification procedure or the manufacturer's instructions.