Jännityskeskittymän

Jännityskeskittymä, also known as stress concentration, is a geometric feature in a part that causes stress to accumulate in a localized area. These can occur at sharp corners, holes, notches, or any abrupt change in the cross-section of a material. When a load is applied to a component, the stress is not uniformly distributed across its surface. Instead, the presence of a geometric discontinuity redirects the flow of stress, causing it to become significantly higher in the vicinity of the discontinuity compared to the average stress in the material.

The magnitude of this stress increase is quantified by the stress concentration factor, denoted by K_t. This factor is a ratio of the maximum stress at the discontinuity to the nominal or average stress. A higher stress concentration factor indicates a greater likelihood of failure at that point. Even if the overall stress on a component is well below the material's yield strength, a high stress concentration can lead to premature fracture or fatigue failure.

Understanding and mitigating stress concentrations is crucial in engineering design, particularly in applications subjected to cyclic loading or high stress levels. Designers often employ strategies such as filleting sharp corners, rounding holes, or using smooth transitions in cross-sectional areas to reduce the severity of stress concentrations. Finite element analysis (FEA) is a common computational tool used to predict and analyze stress distribution and identify areas of high stress concentration in complex geometries.