Lämpötilajännite

Lämpötilajännite, also known as thermal stress, is a mechanical stress that arises from temperature changes within a material or structure. When a material is heated, it expands, and when it cools, it contracts. If this expansion or contraction is constrained, either by the material's own geometry or by external forces, internal stresses are generated. These stresses are referred to as temperature stresses or thermal stresses.

The magnitude of the temperature stress depends on several factors, including the coefficient of thermal expansion of the material, the temperature change, and the degree of constraint. Materials with a high coefficient of thermal expansion will experience greater dimensional changes and thus higher stresses for a given temperature change. Similarly, greater temperature changes will lead to larger stresses. Constraints, such as being fixed at both ends or being part of a larger, rigid structure, prevent free expansion or contraction, forcing the material to deform against the applied thermal forces, thus inducing stress.

Temperature stresses can be significant and can lead to various problems. In mechanical components, they can cause deformation, fatigue, and even fracture if the stresses exceed the material's strength. For example, in bridges or large buildings, expansion joints are incorporated to accommodate thermal expansion and contraction, preventing the buildup of excessive temperature stresses. In electronic components, differential thermal expansion between different materials can lead to stress and eventual failure. Understanding and accounting for temperature stresses is crucial in the design of many engineering applications to ensure their safety and reliability.