Matalasykliväsymys

Matalasykliväsymys, also known as low-cycle fatigue, is a phenomenon where a material weakens and eventually fails due to repeated stress cycles. Unlike high-cycle fatigue, which occurs at lower stress levels over many cycles, low-cycle fatigue involves larger stress amplitudes that cause significant plastic deformation with each cycle. This leads to the initiation and growth of cracks relatively quickly.

The process of low-cycle fatigue typically begins with the accumulation of micro-cracks within the material. These cracks propagate with each subsequent stress cycle. Eventually, when the total crack length reaches a critical size, the material can no longer withstand the applied load, leading to catastrophic failure. The rate of crack growth in low-cycle fatigue is often influenced by factors such as the material's properties, the magnitude and frequency of the stress cycles, and the environmental conditions.

Materials susceptible to low-cycle fatigue include those that exhibit ductility, meaning they can deform plastically before fracturing. Common examples where low-cycle fatigue is a concern are in aerospace components, power generation turbines, and structures subjected to thermal cycling. Understanding and predicting low-cycle fatigue is crucial for ensuring the safety and reliability of these engineering applications. Design considerations often involve limiting the stress amplitudes or incorporating materials with higher fatigue resistance.