Investigation of the stress–strain state of racks of light steel thin-walled structures by the method of digital image correlation

Abstract

The article discusses the features of the work of thin-walled profiles of light steel thin-walled structures (LSTS), used for the construction of prefabricated buildings. A brief description is given of the theory of stability of thin-walled rods based on the law of flat sections (Euler bending forms), the necessity of taking into account the seventh degree of freedom (deplanation of the cross section) when calculating LSTS for stability is revealed. The results of experimental studies of the stress–strain state (SSS) of LSTS under the influence of static compressive loads are presented. Relative deformations were monitored using strain gages and the digital image correlation method implemented in the Vic-3D digital optical system. The dependences of the main compressive stresses of the rack shelves on the applied compressive load and the field distribution of the relative longitudinal deformations of the rack walls as a result of speckle image processing in the Vic-3D system are presented. It was established that the loss of the bearing capacity of the studied LSTS from the loss of stability occurred from actual deformations, the values of which are significantly larger than the values ​​of the calculated deformations obtained from the calculation of stability based on the application of the law of flat sections.