Different materials can be subjected to the fatigue test, depending on the purpose in which they are intended for. Metals and composites are commonly subjected to fatigue tests because these materials are commonly used in applications where components are repetitively subjected to forces that can either bend or break them. Making sure that these materials have a high fatigue limit is essential for these applications, so they are commonly subjected to such tests. Other materials such as polymers, wood, and ceramics may also be fatigue tested to determine their suitability for specific applications.