Roller

Defines the spring stiffness and dash pot damping properties of rollers in a Roller Contact component.

1. Parameters

  • Damping: Dash-post damping coefficient

  • Stiffness, options are

    • Constant stiffness: ☑

    • Nonlinear stiffness: ☐

1.1. Constant contact spring properties

  • Spring stiffness (bi-linear or non-linear)

  • Radius: Radius of roller

The spring is active when the distance between the roller axis and the pipe is less than \(\Delta_0 = \mathrm{radius + RTUBE}\), where RTUBE is the external radius of the pipe cross-section, see Figure 1.

image
Figure 1. Constant spring.

1.2. Nonlinear stiffness characteristics

  • Force: Pressure force corresponding to compression

  • Compression: Spring compression stiffness

The specified stiffness characteristics is moved to account for the external radius of the tube (RTUBE).The external radius is calculated based on the external area of the actual cross section, see Figure 2.

image
Figure 2. Nonlinear stiffness