Alternating stress
The term alternating stress clarifies the effects of stress acting in different directions or with varying strengths , which can change the structure of a (mostly) metallic material. If the material lacks the necessary elasticity (mostly brittle alloys), the structure is destroyed. In practice, this means stress cracks that can lead to breakage of the material.
species
Alternating stresses are caused by stresses acting with different strengths, for example alternating tensile-compressive stresses, for example due to pressure fluctuations in a pressure vessel ( alternating pressure stress), through temperature changes during heating or cooling processes ( alternating temperature stress or alternating thermal stress ) or through changes in external or internal loads (wind loads, different filling level of a container).
impact
Alternating, cyclical loads lead to fatigue damage if the permissible number of load cycles is exceeded. This is known as reaching fatigue life.
Individual evidence
- ↑ DIN EN 13445 Part 3, sections "Simplified calculation of the fatigue life", "Detailed calculation of the fatigue life"