Stressspitzen

Stressspitzen, also known as stress concentrations, are localized areas within a material where stress levels are significantly higher than the average stress applied to the object. These occur at geometric discontinuities or flaws. Common examples include sharp corners, holes, notches, cracks, or any sudden change in cross-section. The presence of a stressspitze means that the material in that specific region is subjected to a much greater load than the rest of the structure, even if the overall applied load is moderate.

The magnitude of a stressspitze is quantified by the stress concentration factor, often denoted by the Greek letter beta (β) or K_t for elastic stress. This factor represents the ratio of the maximum localized stress to the nominal or average stress. A higher stress concentration factor indicates a more severe concentration of stress.

Stressspitzen are critical in the design and analysis of mechanical components because they can be the initiation points for fatigue failure or fracture. Even under static loads, if the localized stress exceeds the material's yield strength, plastic deformation will begin at the stressspitze. Under cyclic loading, repeated stress cycles at these high-stress regions can lead to crack initiation and propagation, eventually causing the component to fail prematurely. Therefore, engineers often employ design strategies to minimize or eliminate stressspitzen, such as using rounded corners and avoiding sharp features, or by employing materials with higher fracture toughness.