Define the Properties of Spring Dampers

The Properties tab on the Spring Dampers panel allows you to define the translational or rotational stiffness and damping properties of coil or torsion springs respectively.

1. Click the Properties tab.
2. For a coil spring damper, define the spring force (K) using the options in the drop down menu.
   If Linear is chosen, enter a real and positive for the linear stiffness coefficient of the coil spring.
   If Curve is chosen, define the spring force transmitted through the spring damper, expressed in the form of a curve which is a function of an independent variable.
   1. Select AKIMA, CUBIC, LINEAR , or QUINTIC under Interpolation as the method of interpolation of between two data points on the curve.
   2. Enter a value under Independent variable.
      By default, the independent variable is filled with the expression {sd.DM}, where sd is the variable name of the spring damper.
   3. Resolve the curve by double-clicking the Curve collector and selecting a curve from the Select a Curve dialog.
      Note: To use a curve, you first need to define a curve (using the Curves panel) which represents the behavior of the spring damper.
   If Sline3D is chosen, define the spring force transmitted through the spring damper, expressed in the form of a 3D spline which is a function of two independent variables.
   1. Select AKIMA, CUBIC, LINEAR , or QUINTIC under as the method of interpolation of values between 2 data points in XY plane.
   2. Resolve the 3D spline by double-clicking on the Spline3D collector and selecting a Spline3D entity from the Select a Spline3D dialog.
      Note: To use a Spline3D entity, you first need to define a spline using the Spline3D panel.
   3. Specify an expression for Independent variable X and Independent variable Z.
      By default, the Independent variable X is filled with the expression {sd.DM}, where sd is the variable name of the spring damper.
   If Expressions is chosen, enter a solver expression to define the spring force transmitted through the spring damper.
3. Similarly, define the damping force (C) of the coil spring using the options in the drop down menu.
   If Curve is chosen, by default, the independent variable is filled with the expression {sd.VR}, where sd is the variable name of the spring damper.
   If Spline3D is chosen, by default, the Independent variable X is filled with the expression {sd.VR}, where sd is the variable name of the spring damper.
4. For a torsion spring damper, define the spring force (KT) using the options in the drop down menu.
   If Linear is chosen, enter a real and positive for the linear rotational stiffness coefficient of the torsion spring.
   If Curve is chosen, define the spring torque transmitted through the torsion spring, expressed in the form of a curve which is a function of an independent variable.
   1. Select AKIMA, CUBIC, LINEAR , or QUINTIC under Interpolation as the method of interpolation of between two data points in the curve.
   2. Enter a value under Independent variable.
      By default, the independent variable is filled with the expression {sd.AZ}, where sd is the variable name of the spring damper.
   3. Resolve the curve by double-clicking the Curve collector and selecting a curve from the Select a Curve dialog.
      Note: To use a curve, you first need to define a curve (using the Curves panel) which represents the behavior of the spring damper.
   If Sline3D is chosen, define the spring force transmitted through the spring damper, expressed in the form of a 3D spline which is a function of two independent variables.
   1. Select AKIMA, CUBIC, LINEAR , or QUINTIC under as the method of interpolation of values between 2 data points in XY plane.
   2. Resolve the 3D spline by double-clicking on the Spline3D collector and selecting a Spline3D entity from the Select a Spline3D dialog.
      Note: To use a Spline3D entity, you first need to define a spline using the Spline3D panel.
   3. Specify an expression for Independent variable X and Independent variable Z.
      By default, the Independent variable X is filled with the expression {sd.AZ}, where sd is the variable name of the spring damper.
   If Expressions is chosen, enter a solver expression to define the damping transmitted through the spring damper.
5. Similarly, define the damping force (CT) of the torsion spring using the options in the drop down menu.
   If Curve is chosen, by default, the independent variable is filled with the expression {sd.WZ}, where sd is the variable name of the spring damper.

   If Spline3D is chosen, by default, the Independent variable X is filled with the expression {sd.WZ}, where sd is the variable name of the spring damper.