7.1.1 2D Load Functions

The Modeler2D load functions are used to specify forces and moments applied to specific bodies in the mechanism model. In general, moments are specified by magnitude, and forces are specified by magnitude and line of action.
By using Modeler2D axis objects to define the line of action, a force can be applied to a point attached to any body in the mechanism, and the direction of the force can be a global or local vector, or a line from one body to another. The magnitude of a force or moment applied to a static model can be a constant, or it can be a function of location or velocity-dependent variables or even a function of the reaction forces at specified constraints. An applied load that is a function of constraint reaction forces is often used to model friction.

2D load functions.

An option for Force.

Modeler2D load objects are typically used in a similar manner to Modeler2D constraint objects. They are defined prior to adding them to the model and then passed to SetLoads. Some examples of valid load objects follow.

This loads the Modeler2D package.

In[1]:=

Here is a moment of magnitude 4 applied to the crank.

In[2]:=

Out[4]=

Here is a moment applied to the crank with magnitude equal to twice the rotation angle of the crank.

In[5]:=

Here is a force applied to the crank passing through point {1,1} on the crank and pointing in the global X direction, with magnitude equal to k times the distance from the point of application to the global origin.

In[6]:=

The Gravity function needs to know the mass and the location of the centroid of each body to apply the gravitational force. These properties are defined with the Mass and Centroid options for the Modeler2D Body function, and added to the model with SetBodies. See Section 8.1.