EngineerBenchLinear thermal expansion from a temperature change
A part's length change is its initial length multiplied by its coefficient of linear expansion and the temperature change. A positive temperature change produces growth for a positive coefficient. The reverse mode finds the temperature change needed to produce an entered change in length.
Temperature change is not absolute temperature
A rise of 10 °C is a difference, not a final temperature of 10 °C. Fahrenheit temperature differences use a scale conversion without the absolute-temperature offset. Enter the change between the two conditions, with the appropriate difference unit selected.
Free expansion versus restraint
This model estimates free, uniform expansion with a constant coefficient. A constrained part can develop stress instead of moving freely. Temperature gradients, changing material properties, and differential expansion between mating parts require additional consideration.
Estimating the size of a movement
For a one-meter part with an assumed expansion coefficient of 12 micrometers per meter per degree Celsius, a 50 °C rise produces 0.6 mm of free expansion. The coefficient expresses change relative to original length for each degree of temperature change. Length and temperature rise both scale the result directly in this constant-coefficient model.
Use the coefficient for the material and relevant temperature range rather than selecting a value only by a broad material name. Some materials are direction-dependent, and assemblies can combine several materials with different coefficients. If you are comparing a hot component with its support, calculate the relative movement along the actual constrained direction. A negative temperature change represents cooling and produces contraction for a positive coefficient. The inverse calculation finds the temperature difference associated with a requested free movement; it does not predict how a heat source brings the component to that temperature or how quickly the temperature becomes uniform.
Formula
ΔL = α L ΔT. The temperature field is a difference, not an absolute temperature.