Viscoelasticity

A property of materials that exhibit both viscous and elastic characteristics when undergoing deformation

Viscoelasticity is a property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. This property is particularly important in the study of biological tissues, polymers, and other complex materials. Viscoelastic materials have the ability to dissipate energy, which is a key factor in their behavior under stress and strain.

Properties of Viscoelastic Materials

Viscoelastic materials are characterized by their time-dependent strain response to stress. This means that the deformation of the material is not only dependent on the applied stress but also on the duration for which the stress is applied. The key properties of viscoelastic materials include:

Creep

Creep is the tendency of a viscoelastic material to deform permanently under a constant load over time. When a constant stress is applied, the material will initially deform elastically, but over time, it will continue to deform at a decreasing rate.

Stress Relaxation

Stress relaxation is the decrease in stress experienced by a viscoelastic material when it is held at a constant strain. Over time, the material will adjust to the strain, resulting in a reduction of the internal stress.

Hysteresis

Hysteresis refers to the energy loss in a viscoelastic material when it is subjected to cyclic loading and unloading. This energy loss is due to the internal friction within the material, which causes the stress-strain curve to form a loop.

Dynamic Moduli

The dynamic moduli, including the storage modulus and the loss modulus, describe the material's response to oscillatory stress. The storage modulus represents the stored energy, while the loss modulus represents the energy dissipated as heat.

Mathematical Models

Several mathematical models are used to describe the behavior of viscoelastic materials. These models help in predicting the response of materials under various conditions.

Maxwell Model

The Maxwell model represents a viscoelastic material as a combination of a spring and a dashpot in series. It is useful for modeling materials that exhibit stress relaxation.

Kelvin-Voigt Model

The Kelvin-Voigt model consists of a spring and a dashpot in parallel. It is used to describe materials that exhibit creep behavior.

Standard Linear Solid Model

The standard linear solid model, also known as the Zener model, combines elements of both the Maxwell and Kelvin-Voigt models to provide a more comprehensive description of viscoelastic behavior.

Applications in Medicine

Viscoelasticity is a critical property in the field of medicine, particularly in the study of biomechanics and tissue engineering.

Biomechanics

In biomechanics, the viscoelastic properties of tissues such as tendons, ligaments, and cartilage are essential for understanding their function and response to mechanical loads. These properties influence how tissues absorb shock and distribute forces throughout the body.

Tissue Engineering

In tissue engineering, understanding the viscoelastic properties of scaffolds and biomaterials is crucial for designing materials that mimic the mechanical behavior of natural tissues. This knowledge helps in developing implants and prosthetics that integrate well with the body.

Related Pages

• Elasticity (physics)
• Viscosity
• Biomechanics
• Tissue engineering

Viscoelasticity

• Non-Newtonian fluid

• Elastic vs. viscoelastic material

• 

  Comparison of three and four element models

• 

  Maxwell diagram

• Kelvin-Voigt diagram

• 

  SLS

• SLS2

• Jeffreys rheological model

• Burgers model 2

• Burgers model

• Weichert

• Visco