How is viscoelastic material defined in Abaqus?

How is viscoelastic material defined in Abaqus?

in abaqus for modelling viscoelastic material in time domain there are three ways:

1. combined test data.
2. shear test data.
3. volumetric test data.

What is viscoelastic damping?

Abstract. Viscoelastic (VE) dampers have been successfully incorporated in a number of tall buildings as a viable energy dissipating system to suppress wind- and earthquake-induced motion of building structures. This type of damper dissipates the building’s mechanical energy by converting it into heat.

Which material is considered viscoelastic?

Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Synthetic polymers, wood, and human tissue, as well as metals at high temperature, display significant viscoelastic effects.

What is the formula for frequency when the material is viscoelastic?

Power law frequency dependence where a and b are real constants, g∗1 and k∗1 are complex constants, and f=ω/2π f = ω / 2 ⁢ is the frequency in cycles per time.

What is Anelastic deformation?

Deformation constitutes both change in shape, distortion, and change in size/volume, dilatation. Time dependent recoverable deformation under load is called anelastic deformation, while the characteristic recovery of temporary deformation after removal of load as a function of time is called elastic aftereffect.

What is prony series?

A nonlinear least squares regression algorithm is employed. The measured data includes ramp loading, relaxation, and unloading stress-strain data. The resulting Prony series, which captures strain rate loading and unloading effects, produces an excellent fit to the complex loading sequence.

What is loss factor viscoelastic materials?

The loss factor of viscoelastic materials as a function of frequency has at least one peak. It is shown that the magnitude and width are interrelated through the dispersion of dynamic modulus and the rate of frequency variation of loss factor.

Is a visco elastic damping compound?

Vibrating surfaces are often dampened by applying visco-elastic materials directly to the surface, thus converting the vibration energy to heat. The flexing of the damping material provides the energy dissipation and “decay” to reduce noise.

What are viscoelastic materials used for?

Viscoelastic materials are used in automobile bumpers, on computer drives to protect from mechanical shock, in helmets (the foam padding inside), in wrestling mats, etc. Viscoelastic materials are also used in shoe insoles to reduce impact transmitted to a person’s skeleton.

Is plastic a viscoelastic material?

The primary property that makes most plastics so attractive over other materials is viscoelasticity. This gives plastic the ability to absorb energy, flex and spring back without cracking.

What are Anelastic materials?

An anelastic material is one that shows a temporal shift between an applied stress and the resulting strain. If the applied stress is periodic as shown in the diagram, this material behavior will result in a phase shift between the stress and strain in the steady state.

What is the use of viscoelasticity model in Abaqus?

Viscoelasticity model in Abaqus is useful for materials in which dissipative losses primarily caused by viscous (internal damping) effects. The model must be combined with an elastic material model. Viscoelasticity cannot be combined with any of the plasticity models.

What type of material damping is used in Abaqus?

For many applications such damping may be adequate. Another option is to use Rayleigh damping or structural damping. In Abaqus, material damping can be defined for both direct-integration (nonlinear, implicit or explicit) and mode-based (linear) dynamic analyses.

How does Abaqus define linear isotropic elasticity?

Abaqus assumes that the viscoelastic material is defined by a Prony series expansion of the dimensionless relaxation modulus: , i = 1, 2, …, N , are material constants. For linear isotropic elasticity, substitution in the small-strain expression for the shear stress yields γ(t – s)ds.

What is viscous damping?

The most widely used damping form called viscous damping, in which the damping force is velocity proportional. In fact, the complex damping may be proportional to the square of velocity, such as the damping force of solid motion in liquid, and sometimes it even has nothing to do with speed, such as the friction at the supports.