// multi-utility computation suite · offline · instant · precise
┌──────────────────────────┐
│ [c] calcalyst_ │
│ computation suite │
└──────────────────────────┘
// select a module to initialize
/ search↵ open firstesc close
// adsenseEMPTY_LEADER_SLOT728×90
// adsenseMOBILE_ANCHOR_SLOT320×50
// keyboard_shortcuts
/focus search
↑↓navigate module list
Enter
open first result from search
open highlighted
compute when module is open
compute when focused in a field
Escclose module · clear selection
⌫
eng.fatigue-sn-curve Calculator
Calculates fatigue life (cycles to failure) from applied stress amplitude using the Basquin power law (S-N curve) and endurance limit. Steel has a true endurance limit at approximately 50% of ultimate tensile strength — aluminium has no endurance limit and will eventually fail at any cyclic stress.
Inputs
Ultimate Strength Mpa
Maximum stress before fracture. Structural steel: 400–700 MPa. Aluminium alloys: 200–500 MPa.
Endurance Limit Mpa
Reference formula or conversion factor shown for context.
Applied Stress Mpa
Internal force per unit area (Pa or MPa). Must stay below yield strength in service.
Stress Concentration Kt
Amount of solute per unit volume. Higher concentration = more solute dissolved.
Results
fatigue life Nf (cycles)
The value at the specified point or condition.
endurance limit Se (MPa)
Sample size or count used in the calculation.
notched stress σ_a·Kt (MPa)
Internal force per unit area (Pa or MPa). Must stay below yield strength in service. Beyond yield: permanent deformation. Beyond tensile strength: fracture.
S-N slope b
The gradient -- rise divided by run. In finance, rate of change per unit time.
Se (steels) ≈ 0.5 UTS up to ~1400 MPa
Reference formula or conversion factor shown for context.