# Scale Factors P0, P1, P2, and Q0, Q1, Q2

These factors are used to represent friction in the bushing material and also other effects such as viscoelasticity.

The overall scale factor is defined on the left for stiffness and on the right for damping as follows:

The following plot shows the behavior of the scaling function ${S}_{y}$ for various values of $|y|$ and ${p}_{2}$ . Note that the y-axis is plotted on a log scale to make the effects more obvious.

The functional form of ${S}_{y}$ is selected as it easily represents a variety of shapes with very few parameters.
Note: ${S}_{y}$ and ${S}_{w}$ are primarily responsible for capturing the dependency of the dynamic stiffness and loss angle on the amplitude of the input.

The next figure shows the same data as the figure above, except $|y|$ is the x-axis and ${p}_{2}$ the curve parameter: