# Stability

The following discussion of stability follows Zhang and Guest, who state, "Stability is related to level of self-stress and material properties." [1] See also Connelly, R

## Minimum Energy Stability (Rest State)

A structure is considered stable if and only if, when subject to small disturbances, it returns to its original configuration. This occurs when the structure's configuration is a minimum energy state, and disturbances lead to an increase in energy that can then be shed.

## Prestress Stability

Assume that the stiffness of members is infinite compared to level of self-stress. If the structure is stable in this case, then it is said to have prestress stability. Any stable tensegrity has prestress stability, but the inverse is not always correct.

## Super Stability

Super stability is unconditional stability, regardless of the level of self-stress and material properties. It is the preferred stable state for tensegrity structures.

## Instability Due to Divisibility

Some tensegrity structures can be physically and mechanically divided into several identical substructures. If these substructures have relative motions, the original structure is obviously unstable.