Only static equilibrium equations are used here, so the investigated system must be

The necessary condition is that the number of equilibrium equations equals the number of unknown reaction forces.

In case of a statically indeterminate system only the degree of statical indeterminacy will be calculated.

Steps to set up a new model:

- define coordinates of all relevant points (bearings, hinges and load locations).

The mouse can be used: double click to create new points, click drag to move existing points - define each part of the structure by a list of points, a part with only 2 points is a truss.

The mouse can be used: click the points, double click to finish a list - define for points with bearings, which direction is supported
- define loads (forces and/or moments)

If a part is defined by only 2 points it will be interpreted as a

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when no resulting force or moment acts on it. That gives 3 scalar equilibrium equations for each body.

Therefore, all bodies and pendulum rods are cut free and 3 equilibrium conditions are created in each case,

in which, in addition to the known loads, the hinge forces are also included as unknowns, 2 per hinge.

The bodies are connected to one another via the hinges. There is a central system of forces in each case.

Therefore, 2 equilibrium conditions are created for each coupling hinge.

An equation is also created for each floating bearing, which, depending on its orientation, sets one of the two bearing forces to 0.

With

The unknowns of this system of equations are the 2 reaction forces per hinge that are independently introduced for each body and bearing.

When it comes to "hand calculations", the procedure is slightly different, e.g. pendulum rods are not treated as bodies, but only as single-value power transmitters.

This significantly reduces the number of equations required, especially for truss frameworks.

A necessary condition is that the number of equations equals the number of unknowns.

All reaction forces will be calculated in this case.

The system is

In this case only the degree of statical indeterminacy will be calculated and displayed.

Reaction forces cannot be calculated without information about the deformation behavior of the components of the system.

The system is

Kinematical indeterminacy means that parts of the system or the system as a whole can move.

In this case the degree of kinematical indeterminacy will be calculated and displayed, and if equilibrium is possible, the reaction forces are also calculated.

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