This component is used to exert a line force
between the origin of frame_a and the origin of frame_b
by attaching components of the 1-dimensional translational
mechanical library of Modelica (Modelica.Mechanics.Translational)
between the two flange connectors flange_a and
flange_b. Optionally, there is a point mass on the line
connecting the origin of frame_a and the origin of frame_b.
This point mass approximates the mass of the force element.
The distance of the point mass from frame_a as a fraction of the
distance between frame_a and frame_b is defined via
parameter lengthFraction (default is 0.5, i.e., the point
mass is in the middle of the line).
In the translational library there is the implicit assumption that
forces of components that have only one flange connector act with
opposite sign on the bearings of the component. This assumption
is also used in the LineForceWithMass component: If a connection
is present to only one of the flange connectors, then the force
in this flange connector acts implicitly with opposite sign also
in the other flange connector.