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Description
ℹ️ General Information
Component Name: Damage Accumulation Rule according to Palmgren-Miner
Component Location: core/damage_cumulation
Suggested Python Names: damage_cumulation_elementary, damage_cumulation_basic, damage_cumulation_haibach
FABER WG Relation: 4.5
Brief Description: three functions to deal with the Palmgren-Miner linear damage accumulation depending on the choice of its version:
Priority: 10
Technical Complexity: 2
Estimated Effort: 1
Dependencies: -
Implementation Details
📋 Specification
There are at least these three functions to deal with the Palmgren-Miner linear damage accumulation depending on the choice of version:
- Elementary version - the same slope k of the S-N curve below and above the fatigue limit
- Basic version - the S-N curve gets horizontal at the fatigue limit, no damage for stresses beneath
- Haibach version - the original slope_k is modified below fatigue limit to 2*slope_k-1
Inputs
(1) Parameters of the S-N curve in the power law sig^k*N=C: (a) slope k, (b) constant C
(2) Fatigue limit value sig_FL
(3) Pairs of load spectrum: stress sig, number of occurrences n
Outputs
Damage caused by each input pair
Required behavior
For the stresses at and above the fatigue limit, the damage is computed from the input law:
D=n/N=n*sig^k/C
For the response below the fatigue limit, the response differ based on the version to be implemented:
1) Palmgren-Miner elementary
The same rule as above the fatigue limit is applied to compute damage
2) Palmgren-Miner basic
D=0
3) Palmgren-Miner by Haibach
D=nsig^(2k-1)/(C*sig_FL^(k-1))
Resources for understanding if necessary
- Graphical interpretation of the change in the S-N curve based on the chosen version can be found e.g. in this open-access paper: http://dx.doi.org/10.5545/sv-jme.2013.1348
- The principles of the linear damage accumulation can be grasped from this post: https://community.sw.siemens.com/s/article/calculating-damage-with-miner-s-rule
Tests/validation information if necessary
For k=5, C=1e15, sig_FL=137.97
n=5000, sig=150: D=3.8e-3 for any variant
n=100000, sig=110:
Elementary: D=1.61e-2
Basic: D=0
Haibach: D=6.51e-3