Usage Ratio is actually the Accumulated Damage Ratio. It is calculated for EACH NODE.

The APPLIED NO. OF CYCLES is IDENTICAL FOR THE WHOLE MODEL, so that, for each NODE, the Applied No. of Cycles is the same.

Consequently, the HIGHEST "Usage Ratio", representing the Applied No. of Cycles vs. Allowable No. of Cycles, yields to the MINIMUM Allowable No. of Cycles.

NOTE.

If ONLY ONE CYCLIC LOAD or STRESS RANGE is considered in analysis, then the Highest Usage Ratio and Minimum Allowable No. of Cycles correspond to the HIGHEST CYCLIC STRESS RANGE RATIO found by CII analysis. The Minimum Allowable No, of Cycle may be (actually it is!) taken from the applicable Fatigue Curve, based on that Highest Stress Range found by the stress analysis.

Otherwise, if 2 or more cyclic loads or stress ranges are to be considered, the Accumulated Damage Ratio (or "Usage Ratio" as named by CII developers) needs to be calculated for each section/node. The actual/minimum allowable no. of cycles is established from the Highest "Usage Ratio" value.