Creep Rate Calculator - Material Deformation & Strain Rate Analysis
Results:
Creep Strain
0.5000%
Creep Rate (s⁻¹)
5.000e-6
Rate (per hour)
1.800e-2
Length Change
0.500 mm
Formula: Creep Rate = (ΔL/L₀) / t = 0.005000 / 1000 = 5.000e-6 s⁻¹
How Creep Rate Calculation Works
Measure Lengths
Initial and final dimensions
Record Time
Duration of deformation
Calculate Rate
Apply creep formula
Formulas and Calculations
Creep Rate Formula
ε̇ = dε/dt = (ΔL/L₀) / Δt
Where:
ε̇ = Creep rate (strain per unit time)
ε = Strain = (L - L₀)/L₀
t = Time duration
Norton's Power Law
ε̇ = A σⁿ exp(-Q/RT)
A = Material constant
σ = Applied stress
n = Stress exponent
Q = Activation energy
R = Gas constant, T = Temperature
Creep Rate Examples
| Material | Temp (°C) | Stress (MPa) | Creep Rate (s⁻¹) |
|---|---|---|---|
| Steel (Carbon) | 400 | 100 | 1.0×10⁻⁹ |
| Steel (Stainless) | 600 | 150 | 5.0×10⁻⁹ |
| Aluminum | 300 | 50 | 2.0×10⁻⁸ |
| Copper | 400 | 75 | 1.5×10⁻⁸ |
| Titanium | 500 | 200 | 3.0×10⁻⁹ |
| Nickel Alloy | 700 | 300 | 1.0×10⁻⁸ |
| Lead | 100 | 10 | 1.0×10⁻⁶ |
| Zinc | 150 | 20 | 5.0×10⁻⁷ |
| Magnesium | 200 | 30 | 2.0×10⁻⁷ |
| Concrete | 50 | 5 | 1.0×10⁻¹¹ |
| Polymer (HDPE) | 80 | 2 | 1.0×10⁻⁷ |
| Ceramic (Al₂O₃) | 1000 | 100 | 1.0×10⁻¹⁰ |
| Tungsten | 1200 | 500 | 1.0×10⁻¹⁰ |
| Molybdenum | 1000 | 400 | 5.0×10⁻¹⁰ |
| Inconel 718 | 650 | 600 | 2.0×10⁻⁹ |
Creep Rate Comparison
Steel at 400°C
Aluminum at 300°C
Lead at 100°C
Concrete at 50°C
Polymer at 80°C
Ceramic at 1000°C
Practice Problems
Problem 1:
Steel bar: L₀=100mm, Lf=100.2mm, t=1000h. Find creep rate.
Solution: ε̇ = (0.2/100)/3600000 = 5.56×10⁻¹⁰ s⁻¹
Problem 2:
Creep rate 1×10⁻⁸ s⁻¹, time 500h. Find total strain.
Solution: ε = 1×10⁻⁸ × 500 × 3600 = 0.018 = 1.8%
Problem 3:
Aluminum: 0.1% strain in 200h. Calculate creep rate.
Solution: ε̇ = 0.001/(200×3600) = 1.39×10⁻⁹ s⁻¹
Problem 4:
Compare creep rates: Steel vs Aluminum at same conditions
Solution: Aluminum typically 10-100× higher than steel
Problem 5:
Temperature effect: Rate doubles every 50°C increase
Solution: Arrhenius relationship with activation energy
Daily Uses of Creep Rate Analysis
Power plant turbine blade life prediction and maintenance
Aircraft engine component design and safety analysis
Nuclear reactor pressure vessel integrity assessment
High temperature piping system design and inspection
Material selection for extreme environment applications