Adams Machinery > Dialog Box - F1 Help > Gear Pair - Mass (Detailed and 3D Contact)

Gear Pair - Mass (Detailed and 3D Contact)

Machinery → Create Gear Pair

By default, Adams View calculates the mass and inertia for a rigid body part based on the part's geometry and material type. The geometry defines the volume and the material type defines the density. The default material type for rigid bodies is steel.

You can change the material type used to calculate mass and inertia or simply specify the density of the part. If you do not want Adams View to calculate mass and inertia using a part's geometry, material type, or density, you can enter your own mass and moments of inertia.

It is possible to assign zero mass to a part whose six Degrees of freedom you constrain with respect to parts that do have mass. You should not assign a part zero mass, however. Any part that has zero mass and translational degrees of freedom can causes simulation failure (since a = F/m). Therefore, we recommend that you assign finite masses and inertias to all parts. In addition, a part without mass cannot have mass moments of inertia.

Learn about Methods for Calculating Mass Properties.

For the option	Do the following
Material (Gear1/Gear2)
Define Mass By	■User Input If you do not want Adams View to calculate mass and inertia using a part's geometry, material type, or density, you can enter your own mass and moments of inertia. ■Geometry and Density You can change the material type used to calculate mass and inertia or simply specify the density of the part. ■Geometry and Material Type The geometry defines the volume and the material type defines the density.
If you select User Input, the following options will be displayed:
Mass	Enter the mass of the gear part.
The parts are located at the center of the gear, with the z-axis as the rotational axis.
Inertia
Ixx/Iyy/Izz	Enter the values that define the principal mass-inertia components of the gear part.
Ixy/Izx/Iyz	Enter the values that define the deviational (cross-product) mass-inertia components of the gear part.
If you select Geometry and Density, the following options will be displayed:
Density	Enter the density value.
Inertia Geometry	■ Exact Define mass by default 'density' option, Adams View uses the part's density and the volume of the geometry to calculate its mass and inertia. ■Approximate Approximate volume of the gear element is calculated based on addition of gear blank (cylinder or cone) dimension and involute thread volume. Bore volume is subtracted from this calculated volume. For cylindrical gears, the cylindrical gear blank dimension is considered whereas front and rear cone dimensions are considered in case of bevel and hypoid. Rack considers the base width and trapezoidal teeth volume. The approximately calculated volume is multiplied by density to calculate mass. Approximate method has significant gain in performance over material and exact-density options. However, the calculated values are slightly less than other methods.
If you select Geometry and Material Type, the following options will be displayed:
Material Type	Enter the material type to be used inertia calculation.
Contact Settings Note: To get a full description of all contact parameters please refer to the online help for the IMPACT function.
Stiffness	Enter a value for the stiffness coefficient of the gear-to-gear contact. Note: The stiffness coefficient should always be the translational stiffness, that is, with units Force/Length.
Exponent	Enter a value for the contact exponent of the gear-to-gear contact.
Damping Coefficient	Enter a value for the damping coefficient of the gear-to-gear contact. Note: The damping coefficient should always be the translational damping, that is, with units Force*Time/Length.
Penetration	The contact penetration parameter defines the depth at which full damping is reached for the contact.
Static Friction Coefficient	Specifies the relative sliding velocity at which the transition between static friction and dynamic friction starts.
Dynamic Friction Coefficient	Specifies the coefficient of friction at a contact point when the slip velocity is larger than the Dynamic Friction Velocity.
Dynamic Friction Velocity	Specifies the relative sliding velocity at which the transition between static friction and dynamic friction ends. At sliding velocities higher than the Dynamic Friction Velocity, the Dynamic Friction Coefficient will be used.