Mechanism Module
================

The analytical back-end of MOMDYN, referred to here as the "Mechanism module," is implemented using Python, taking
very basic data classes (numeric and string) as user inputs to numerous high-level, object-oriented methods.

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Classic Interface
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The classic interface implements several fundamental components for defining kinematics, largely based on the physics
and classical mechanics modules in SymPy. These include constant and time-varying symbols, frames to model orientation,
and vectors and points to model location.

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   classic

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Mechanical Joints
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Mechanical joints are typical of modern multibody software, and combine attributes of the fundamental objects found in
the classic interface. A good reference to common joint definitions may be found in the documentation for the
open-source Modelica project, in the OpenModelica Mechanics Multibody package. While MOMDYN does not use Modelica
code, I will attempt to use similar terminology and input parameters where applicable.

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   joints

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Bodies
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Bodies are used to define the mass and inertial properties of the model. The most basic body is a Particle, which is a
mass that is attached to a Point, without an inertia tensor. Basic RigidBody objects are defined, which also have mass
defined at the body's mass-center, and inertia tensors dependent on the body geometry.

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   bodies

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Loads
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Loads are the forces and moments that are exerted on points and frames in the model, respectively. These include
external loads, which act on a single point or frame, or external loads that act with equal and opposite amounts on
pairs of points or frames. Additionally, spring behavior can be implemented in translational and rotational forms.


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   loads