Pair the stress-band data
Keep each applied count n with the N corresponding to that same stress range and fatigue detail.
ELECTRICAL & DUTY / TOOL 30
Miner Fatigue Damage Calculator
Sum linear cumulative damage after the fatigue-model cycles for each stress band have already been established.
Before you start: required inputs
- Obtain the applied cycle count for each stress-range band from the assessed history.
- For each band, obtain matching fatigue-model cycles N from the selected S–N curve, detail category, stress definition and environment.
Calculation diagram
A PRACTICAL WALKTHROUGH
How to use this calculator
Exclude unused bands
Use zero applied cycles for unused bands. Retain a positive N so every ratio remains defined.
Review damage contributions
Read each n/N contribution and their sum D. Apply the acceptance criteria of the selected fatigue method separately.
Two populated fatigue bands
THE INPUTS
100,000 applied cycles with N = 1,000,000 and 200,000 applied cycles with N = 2,000,000; zero applied cycles in bands 3 and 4.
THE RESULT
Each populated band contributes 0.1, giving a linear cumulative damage sum D = 0.2 over 300,000 applied cycles.
What does the result mean?
01
D is the arithmetic sum of the entered n/N ratios under the linear Miner model.
02
A larger contribution identifies a band that consumes more of the selected fatigue-model capacity.
03
This calculation does not establish remaining safe life, load-sequence effects, crack growth or design acceptance.
Watch for this
Using one N for every band even though their stress ranges differ.
Formula & model conditions +
D = Σ(n_i/N_i)
D is a modelled damage sum; this tool does not assign a design acceptance or remaining safe life.
- Palmgren–Miner linear cumulative damage with four entered stress bands.
- Each N must correspond to the same stress range, fatigue detail, environment and selected fatigue model as its n.
- Sequence effects, mean-stress corrections, crack growth, inspection planning and standard-specific acceptance factors are outside this calculation.
Common questions
Does D below 1 mean the component is safe?
Acceptance depends on the selected fatigue design method, factors, stress model and assessed detail. This tool makes no automatic pass decision.
Can I use lifted tonnes instead of cycle counts?
No. Each input n is a cycle count, and each N is the corresponding fatigue-model cycle count for that stress band.