You might feel that thermal deformation is “invisible” because it often develops slowly with gradually changing temperature. Check out the video showing the thermal expansion of a bimetallic strip below. Thermal deformation exists and it affects the behavior of our products and structures. In this case, the mismatch in coefficients of thermal expansion between the two metal strips results in nonuniform deformation, which leads to curling. Sometimes, the result of a thermal condition can be significant. In a constrained condition, the internal force caused by a temperature change can even lead to buckling failure.
Thermal expansion can also be utilized. The simplest example is a mercury thermometer, which uses the expansion of mercury to measure the temperature. Another practical application of thermal expansion is using hot water or hot air to treat a car dent. After the car bumper/door is heated up, it's very easy to restore the original shape.
In this lesson we will discuss two applications of thermal strain.
Here are the accompanying handout slides for this lesson.