Häviömoduli

Häviömoduli, also known as loss modulus, is a fundamental concept in the field of viscoelasticity. It represents the energy dissipated as heat during the deformation of a material. When a viscoelastic material is subjected to an oscillating stress, it exhibits both elastic and viscous behavior. The elastic component stores energy, while the viscous component dissipates it. The loss modulus quantifies this dissipated energy.

Viscoelastic materials, such as polymers and biological tissues, display time-dependent mechanical properties. Their response to stress depends on the rate of deformation. The loss modulus is one of two components that describe the complex modulus, the other being the storage modulus. The storage modulus relates to the elastic, recoverable part of the deformation, while the loss modulus relates to the viscous, irrecoverable part.

The loss modulus is typically measured using dynamic mechanical analysis (DMA). In a DMA test, a sinusoidal stress or strain is applied to the material, and the resulting strain or stress is measured. The phase difference between the applied and resulting motion is analyzed. A larger phase difference indicates greater energy dissipation, and thus a higher loss modulus. The loss modulus is often denoted by G'' for shear deformation or E'' for tensile/compressive deformation. Its temperature and frequency dependence provides valuable insights into the molecular mobility and relaxation processes within the material.