Tools › Structures › Fatigue › Spectrum Fatigue Life › Example
ASTM E1049-85 §5.4.4: rainflow counting of the nine-reversal history A to I
| Tool | Spectrum Fatigue Life |
| Source | ASTM International (2017). Standard Practices for Cycle Counting in Fatigue Analysis. ASTM E1049-85 (Reapproved 2017), West Conshohocken, PA. Section 5.4.4, Fig. 6 and Table 1. |
| Level | Professional |
Problem
Rainflow count the stress history with peaks and valleys A to I of −2, 1, −3, 5, −1, 3, −4, 4, −2 (in units of stress) and tabulate the cycles by range with their counts.
Inputs to Enter
- History: −2 1 −3 5 −1 3 −4 4 −2 (enter in ksi; the values are far below the S/N threshold so the count is the check)
- Any S/N selection; repeats 1; scatter factor 4
Answers
- Range 3: 0.5 cycle; range 4: 1.5 cycles (one full cycle E–F with mean 1.0, max 3, min −1, plus one half); range 6: 0.5; range 8: 1.0 (two half cycles C–D and G–H); range 9: 0.5
- Total count 4.0 cycles (Table 1 of the standard)
Notes
The tool's default history is its own 14-cycle block, so paste the nine values. The residue is counted as half cycles as the standard does; a first assumption of 4.5 total was corrected to the standard's 4.0.