To Insert Standard Joints

Because standard joints, except for welding, add degrees of freedom (DOF) to an assembly, you must add one or more standard joints before you can add other categories of joints. You can add one or more standard joints as soon as you start Dynamic Simulation with an assembly open.

Joint type choice

When choosing the type of standard joint to add to a mechanism, consider the degrees of freedom you need between the two components and the relative movements of the two joint coordinate systems . At the time of joint insertion, place the two joint coordinate systems, one on each component. When applying the joint, the software positions the two components so that their joint coordinate systems are coincident. Then, the software creates degrees of freedom, depending on the joint type, between the two coordinate systems and, therefore, between the two components.

In the following table, the subscript numbers refer to the components making up the joint. For example, Z 1 is the Z vector of the first component and Z 2 is the Z vector of the second component.

Preliminary steps

1. Open an assembly.

   Tips included in Prepare assemblies for dynamic simulation tell how you can edit an assembly for easy dynamic simulation.

2. On the ribbon, click Environments tab Begin panel Dynamic Simulation .

3. On the ribbon, click Dynamic Simulation tab Joint panel Insert Joint .

4. To select the joint type, click the down arrow in the joint type box or click the Joints Table icon .

The rest of the steps vary according to the type of joint you are adding. Click the joint type below to see the steps to insert that particular joint type.

Revolution

1. On either the joint type menu or the joints table, select Revolution.

2. In the graphics window, specify the joint coordinate system of component one.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of component one.

   • Select the Z axis.

     The Z axis must be the axis of rotation.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This setting may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Prismatic

1. On either the joint type menu or the joints table, select Prismatic.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the Z axis.

     The Z axis must be along the translational degree of freedom.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Cylindrical

1. On either the joint type menu or the joints table, select Cylindrical.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the Z axis.

     The Z axis must be along the translational degree of freedom, as well as the axis of rotation.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Spherical

1. On either the joint type menu or the joints table, select Spherical.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the origin of the joint coordinate system.

     The origin should be the origin of the three axes of rotation.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

   • Select the Z axis.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Planar

1. On either the joint type menu or the joints table, select Planar.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the X-Z plane on the first component.

     The plane should include both translational degrees of freedom.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

3. Repeat step 2 for the second component.

4. If necessary, click Switch X to flip the direction of an X axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Point-line

1. On either the joint type menu or the joints table, select Point-line.

2. In the graphics window, specify the joint coordinate system of the component containing the line.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the Z axis.

     The Z axis should be along the translational degree of freedom.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Specify the joint coordinate system of the component containing the point.

   • Select the point.
   • Select the Z axis.
   • Select the X axis.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Line-plane

1. On either the joint type menu or the joints table, select Line-plane.

2. In the graphics window, specify the joint coordinate system of the component containing the plane.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the X-Z plane.

     The plane should contain both translational degrees of freedom.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Specify the joint coordinate system of the component containing the line.

   • Select the Z axis.
   • Select the origin of the joint coordinate system.
   • Select the X axis.

4. If necessary, click Switch the plane normal to flip the direction of the plane normal, Switch X to flip the direction of an X axis, or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Point-plane

1. On either the joint type menu or the joints table, select Point-plane.

2. In the graphics window, specify the joint coordinate system of the component containing the plane.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   • Select the X-Z plane.

     The plane should contain both translational degrees of freedom.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Specify the joint coordinate system of the component containing the point.

   • Select the point.
   • Select the Z axis.
   • Select the X axis.

4. If necessary, click Switch the plane normal to flip the direction of the plane normal, Switch X to flip the direction of an X axis, or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Spatial

These joints create six degrees of freedom. Use this option to model a universal joint or other entities, such as, a ball, that have no constraints.

1. On either the joint type menu or the joints table, select Spatial.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   Note: For this joint, you can enter the Z axis, origin, and X axis in any order.

   • Select the Z axis.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This feature makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.

Welding

These joints create no degrees of freedom. Use the joint when you need a rigid connection between two components or to model a weldment. This behavior is useful when you want to generate results for export to FEA.

1. On either the joint type menu or the joints table, select Welding.

2. In the graphics window, specify the joint coordinate system of the first component.

   The joint coordinate system for a component may not be the same as the component coordinate system.

   The software expresses the results in the joint coordinate system of the first component.

   Note: For this joint, you can enter the Z axis, origin, and X axis in any order.

   • Select the Z axis.

     Tip: If you have trouble picking a geometric entity, click and then select the component in the graphics window. This function makes it easier to select an entity in the component.

     While you are not always required to select additional geometric entities to specify the joint coordinate system, it is good practice to specify the joint coordinate system as precisely as possible.

   • Select the origin of the joint coordinate system.

     The joint coordinate system for the first component has its origin at the point at which this component is linked to the second component.

   • Select the X axis.

3. Repeat step 2 for the second component.

4. If necessary, click either Switch X to flip the direction of an X axis or Switch Z to flip the direction of a Z axis.

   This change may be necessary to ensure that the two components are properly positioned when the software moves them so that their joint coordinate systems are superimposed.

5. Click OK.