The standard linear solid (SLS) model is a method of modeling the behavior of a viscoelastic material using a linear combination of springs and dashpots
to represent elastic and viscous components, respectively.
Another coupled model of electrical and mechanical signals based on the spring-dampers (dashpots
) system is proposed by Jerusalem et al.
Analog mechanical models, constructed from linear springs and dashpots
, arranged in series or in parallel, are convenient tools to model the linear viscoelastic behavior under uniaxial loading.
Rheological models usually use differential representation, visualizing the material by the elementary mechanical models composed of elastic springs, plastic sliders, and viscous dashpots
[13, 19, 20].
Viscoelastic relaxation may be represented by a rheological model of springs and dashpots
The connections of suspension system are modelled as a system of linear springs and viscous dashpots
in the vertical direction.
An external viscous dissipation (e.g., due to the surrounding air) is also taken into account by a uniform distribution of linear dashpots
, whose flexural and torsional viscosity coefficients are [c.sub.t] and [c.sub.r], respectively.
Consider a double-Rayleigh beam system consisting of two finite, prismatic, undamped, parallel upper and lower Rayleigh beams joined together by a viscoelastic layer (core) which is modeled as a set of parallel springs and dashpots
as shown in Figure 1.
The masses are connected to linear springs with stiffnesses [K.sub.1] and [K.sub.2] and linear viscous dashpots
with damping constants [C.sub.1] and [C.sub.2].
In a more sophisticated railway vehicle model, the suspension mechanisms are modeled by springs, the damping effect of the suspension systems and air-cushion by dashpots
, and the energy dissipating effect of the interleaf mechanism by frictional devices.
However, in the fractional-derivative model of viscoelastic materials over extended ranges of time and frequency, the deformation work corresponding to springs and losses corresponding to dashpots
(described by fractional derivatives) have both energy types (stored and dissipated) at any point of the utilized materials [27, 28].
The macroscopic stress-strain-time behavior can be described using rheological constitutive models, which consists of a combination of elements such as springs, plastic sliders, and dashpots
that emulate the basic features of the material behavior.