About Springs

In COSMOSMotion you can work with two types of springs:

• Translational springs represent forces acting between two parts over a distance and along a particular direction. You specify the location of the spring on two parts. COSMOSMotion calculates the spring forces based on the distance between the locations of the two parts. COSMOSMotion applies a force to the first part you select, and an equal and opposite force along the line of sight of the second part you select, based on the spring function.

• Torsional springs are rotational springs applied between two components. COSMOSMotion calculates the spring moments based on the angle between the two parts about the specified axis. COSMOSMotion applies a moment about the specified axis to the first part you select, and an equal and opposite reaction moment to the second part you select, based on the spring function.

Example.

The function expressions for the underlying action-reaction forces are:

Translational spring:

- K* (X - X_o)ⁿ + F_o

Torsional spring:

- KT* (Theta - Theta_o)ⁿ + T_o

where:

• X - Current distance between parts at the attachment points

• Theta - Current angle between the parts, about the user-defined spring axis

• X_o- Defines the reference length for the spring. If the reference force of the spring is zero, X_oequals the free length.

• Theta_o- Defines the reference angle for the torsional spring. If the reference torque of the spring is zero, Theta_oequals the free angle.

• F_o - Specifies the reference force at X_o.

• T_o - Specifies the reference torque of the torsional spring at Theta_o.

• n - Exponent. For example, if spring force = kx2, then n = 2 (valid options are -4,-3,-2,-1,1,2,3,4).