Gage R & R for destructive tests
Where quality characteristics of a part significantly changes due to first time measurement, it can be considered destructive. For examples, a rubber hose when assembled may have permanent deformation and force to assemble will change from first time to second time assembly.
In such case, we cannot use traditional approach to gage R & R because repeats are not possible.
In such case, we have take approach from first principles by comparing variation in a batch of samples ( assuming one batch samples are more homogenous) and compare them between the batches.
It is often useful to make sure that gages meet ISO requirements like calibration, linearity etc prior to conducting gage R & R studies.
Arvind