Creep Rate Calculator Formula
Understand the math behind the creep rate calculator. Each variable explained with a worked example.
Formulas Used
Steady-State Creep Rate
creep_rate = prefactor * pow(stress, stress_exp) * exp(-q_j / (8.314 * temp_k))Variables
| Variable | Description | Default |
|---|---|---|
stress | Applied Stress (sigma)(MPa) | 100 |
stress_exp | Stress Exponent (n) | 5 |
temp_k | Temperature(K) | 800 |
activation | Activation Energy (Q)(kJ/mol) | 250 |
prefactor | Pre-exponential Constant (A) | 10000000000 |
q_j | Derived value= activation * 1000 | calculated |
How It Works
Steady-State Creep Rate
Creep is the slow, time-dependent deformation of materials under sustained load at elevated temperatures. The secondary (steady-state) creep rate follows a power-law Arrhenius equation.
Formula
epsilon_dot = A × sigma^n × exp(-Q / (R × T))
where A is a material constant, sigma is the applied stress, n is the stress exponent (3-8 for metals), Q is the activation energy for creep, R = 8.314 J/(mol·K) is the gas constant, and T is absolute temperature.
Worked Example
A nickel alloy at 800 K under 100 MPa (A=1e10, n=5, Q=250 kJ/mol).
stress = 100stress_exp = 5temp_k = 800activation = 250prefactor = 10000000000
- 01sigma^n = 100^5 = 1 × 10^10
- 02Q/(RT) = 250000 / (8.314 × 800) = 37.57
- 03exp(-37.57) = 4.83 × 10^-17
- 04Creep rate = 1e10 × 1e10 × 4.83e-17 = 4.83 × 10^3 s^-1 ... (values depend on actual A)
Ready to run the numbers?
Open Creep Rate Calculator