1. Select two measuring points symmetrically along the length direction on the load line at the outer edge of the slender ring. The measuring point shall be determined on the median vertical line of the inner width of the slender ring.

2. For the circular ring, select two measuring points horizontally and symmetrically at the inner edge of the circular ring, perpendicular to the loading direction and passing through the midpoint of the diameter d of the circular ring. The measuring point should be determined to ensure that the loading force directly passes through the welded part of the ring. In order to facilitate the measurement, reference points are marked with tools such as sample punching, and the measured data are compared with the factory technical data. This label and data should be kept.