Bimetallic Strips

Heat and bending of bimetallic strips. Calculate the bending displacement of bimetallic strips due to temperature changes using the thermal expansion coefficient, length, temperature difference, and thickness.

Bimetallic Strips Calculator

Bi-metallic strips are subject to bending due to heat and can be used to convert change in temperature to mechanical displacement.

Bending occurs towards the side of the metal with the lowest temperature coefficient of expansion.

Formula

s = α × L² × dt / t

Where:

  • s = bending (m)
  • α = thermal expansion coefficient difference (K⁻¹), typically 13-19×10⁻⁶ K⁻¹
  • L = length of bimetallic strip (m)
  • dt = temperature difference (°C)
  • t = thickness of bimetallic strip (m)

Common Materials

  • Steel: 12×10⁻⁶ K⁻¹
  • Copper: 16.6×10⁻⁶ K⁻¹
  • Brass: 18.7×10⁻⁶ K⁻¹
Calculator

Inputs

Results

Bending Displacement (s)-- m
Bending Displacement (s)-- mm
Material 1Material 2α (K⁻¹)Common Use
SteelCopper4.6×10⁻⁶Thermostats
SteelBrass6.7×10⁻⁶Temperature sensors
InvarCopper14.8×10⁻⁶Precision instruments
SteelAluminum8.5×10⁻⁶Thermal switches