A fatigue test is a method used to evaluate the durability and strength of materials or components under repeated loading conditions. This test simulates the effects of cyclic stress, which can lead to material failure over time. Engineers use fatigue tests to determine how long a material can withstand repeated forces before it begins to crack or break. During a fatigue test, samples are subjected to controlled cycles of stress until they fail. The results help in understanding the material's performance in real-world applications, such as in automotive parts or aircraft structures, ensuring safety and reliability in their use.