7.1.3 Generalized Load Function

The Load function is analogous to the Mech Constraint function. Load allows the user to specify an algebraic expression to be added directly to the model's load vector, just as Constraint allows an algebraic constraint to be added to the constraint list.

The generalized load function.

The Load function is typically used only when special generalized coordinates have been added to the model, and it is necessary to apply a load directly to those coordinates. Load basically allows expressions to be added directly to a model's load vector. Using Load to apply a load to a model's Cartesian coordinates is equivalent to applying a force or moment to a body in the model.

Here are Load and Force objects that are functionally equivalent.

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In 3D models, the sym argument to Load has a special caveat: if the Angular solution method was specified with SetSymbols, loads cannot be directly applied to the Euler parameters, because the load vector is formulated in terms of angular velocity. However, loads can be applied directly to the angular velocity coordinates, which is equivalent to applying a pure moment.

Here are Load and Moment objects that are functionally equivalent, when the SetSymbols settings are as specified.

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