dashpot

Figure 1 shows that each bogie supports the cabin with four vertical, lateral, and axial secondary suspensions consisting of spring and dashpot. This model is basically similar to the previous UTM vehicle model [24], except for the lateral control system.

The tunable vibration absorber was composed of mass, spring and dashpot elements and boring bar modeled as a cantilever beam.

Equation [1] is derived from the characteristic equation of motion of a vibrating beam, which idealizes the continuous system as a mass, spring, dashpot system.

Also, the attempt to use science to give "phase angle" or "tan delta" would apply to the spring and dashpot model, but cannot be used for the viscoelastic model of a rubber where the viscosity is due to the need to do work to move neighboring elements held attracted by Van der Waal's forces and elasticity is the entropy effect of stretched chains returning to a random configuration.

A gap element typically has a spring (stiffness) subelement, a friction sub-element (viscous damper or dashpot), and a means for specifying closure distance and direction.

Dashpot coefficients were also applied, and the equation used and values are shown in the next section.

The constants, [p.sub.i=1 or 2] correspond to the characteristic relaxation time, [[mu].sub.i]/[[eta].sub.i] along each branch of the mechanical model, where [eta] is the dampening constant of the dashpot. The glass modulus is defined as [[mu].sub.0] = [[mu].sub.[infinity]] + [[mu].sub.1] + [[mu].sub.2].

(iii) a small damping ratio (measured on the first free mode) is added through a linear dashpot;

The two masses are connected by a spring and dashpot to account for the vehicle suspension (system with 2DOF).