Paris Law Crack Growth

Fatigue crack growth rate da/dN = C·(ΔK)^m. Integrates the life from initial to critical crack size.

StructuralFracture

Paris constant C - Steel in air: 3e-13; in sea water: 5e-13; corrosion fatigue: 1e-12.Paris exponent m - Stress-intensity range ΔKMPa·√m

Crack growth rate da/dN: 0.0000000024m/cycle

Cycles to grow 10 mm at current ΔK: 4,166,667cycles

Changing the inputs requires JavaScript. The calculator above shows its default inputs and result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

\frac{da}{dN} = C \cdot (\Delta K)^m

Symbol	Meaning	Unit
$C$	Paris regression constant
$m$	Paris exponent
$ΔK$	Stress-intensity range	MPa·√m

Source: Paris & Erdogan (1963) - Crack propagation

In short

Fatigue crack growth rate da/dN = C\u00b7(\u0394K)^m.

Learn the theory Hull Strength and Longitudinal Bending