Materialermüdung

Materialermüdung, also known as fatigue, is the weakening of a material caused by repeatedly applied loads. It is a progressive and localized structural damage that occurs when a material is subjected to cyclic loading. Even if the applied stress is well below the ultimate tensile strength of the material, fatigue can cause failure.

The process of fatigue typically begins with the formation of a small crack, often at a stress concentration point such as a surface imperfection or a sharp corner. Under repeated loading, this crack grows incrementally. Eventually, the crack reaches a critical size, and the material fails suddenly and often catastrophically.

Fatigue is a significant concern in many engineering applications, including bridges, aircraft, vehicles, and machinery. Factors that influence fatigue life include the magnitude and type of stress cycles, the material properties, the presence of defects, and the environmental conditions. For instance, higher stress amplitudes generally lead to shorter fatigue lives.

Understanding and predicting material fatigue is crucial for ensuring the safety and reliability of structures and components. Engineers use various methods to assess fatigue resistance, including experimental testing and computational modeling. Design strategies to mitigate fatigue include reducing stress concentrations, selecting appropriate materials, and implementing inspection and maintenance schedules to detect and repair cracks before they become critical.