Abstract: This study considers the relationship between the fundamental frequency of free transverse oscil-lations T of the systems of cross-beams with different sizes of cells on a triangular plan and their maximum deflections W under the action of evenly distributed loads depending on the stiffness characteristics of nodal 0 connections. We constructed dependences of deflections and frequencies of transverse oscillations depending on the rigidity of nodal connections for the systems of cross beams with different cell sizes. We proved that for the systems with cross-beams of the cell sizes a/l<0.17 (a is a cell size, l is a size in terms of the system of cross-beams) the coefficient K with an accuracy to 7.01% corresponds to the theoretical value for the isotropic triangular plates of the constant.