Abstract: it is a complex structure of bars thatall bars are arbitrarily pinned to a rigid body andother structures of bars can be considered as its special cases. In the structure, tensile bars are usually made from a nonlinearly elastic high-strengthmaterial. The exponential function is used to approximately represent the stress-strain curve of thenonlinearly elastic material. The universal expression of the stress-strain calculation in the nonlinearly elastic structures of bars has beed derived andthe general prog...