The lower limit of the first frequency of natural vibrations externally statically indeterminate truss: analytical solution

Abstract

A scheme of a statically determinate planar truss with two additional supports duplicating the main ones is proposed. The formula for the dependence of the lower estimate of the first natural frequency on the number of panels is obtained. The solution is compared with the numerical one. Determination of the forces in the rods by the method of cutting out the nodes and with all the transformations performed in the Maple computer mathematics system. The high accuracy of the result is shown with a large number of panels.