Hysteresiskäyrän

Hysteresis curve, also known as a hysteresis loop, is a graphical representation of the relationship between two variables, typically magnetic field and magnetic flux density, or stress and strain in materials. The term "hysteresis" originates from the Greek word "hysteresis," meaning "a lagging behind." This phenomenon occurs when the output of a system does not depend solely on the current input, but also on the history of the input.

The hysteresis curve is characterized by a loop that does not close, indicating energy dissipation within the system. This is often observed in ferromagnetic materials, where the magnetic flux density lags behind the magnetic field strength during magnetization and demagnetization processes. The area enclosed by the hysteresis loop represents the energy lost per cycle due to hysteresis.

In the context of stress-strain relationships, hysteresis is observed in materials that undergo plastic deformation. The stress-strain curve for such materials exhibits a hysteresis loop, with the material not returning to its original state upon unloading, indicating permanent deformation.

Hysteresis curves are crucial in various fields, including materials science, electrical engineering, and physics. They provide valuable insights into the behavior of materials under different conditions and help in the design and optimization of systems involving magnetic or elastic materials. Understanding hysteresis is essential for predicting the performance and reliability of these systems under various operating conditions.