Coffin-Manson Thermal Fatigue Calculator

N_f = A\,(\Delta\varepsilon)^{-c}

Nf = cycles to failure
A = material constant
Delta eps = strain range
c = Coffin-Manson exponent (positive)

Cycles to Failure (Nf)A ConstantDelta Strain (Delta eps)c (positive)

Solved Nf: 4000000000

Have a more complex case than this calculator covers? Get in touch.

How it works

The Coffin-Manson model predicts fatigue life under thermal cycling — solder joints, wire bonds, and other structures that crack from repeated expansion and contraction. Larger temperature swings (ΔT) mean fewer cycles to failure, so the acceleration factor between a harsh test and milder field use is:

AF = \left(\frac{\Delta T_{test}}{\Delta T_{field}}\right)^{c}

where ΔT is the temperature range of each cycle and c is the Coffin-Manson exponent (roughly 2 for solder fatigue, higher for brittle materials).

Example:Field cycling of ΔT = 40 °C versus an accelerated test at ΔT = 100 °C, with c = 2, gives AF = (100/40)² = 6.25. One test cycle is worth about 6 field cycles, so a 500-cycle test represents roughly 3,000 field cycles for that mechanism.

Use this for thermal-cycling and thermal-shock fatigue. For diffusion- or reaction-driven wear-out, use the Arrhenius calculator instead; to define the real-world ΔT distribution your product sees, start with the Mission Profile tool.