DIAGNOSTICS OF THE PRESS POWER FRAME WITH THREADED CONNECTIONS OF LOAD-BEARING ELEMENTS BY STRAIN GAUGE METHOD

Abstract

The distribution of tightening forces between several threaded connections of power elements of machines and mechanisms directly affects the strength and reliability of the entire structure. When operating heavily loaded mechanisms with threaded connections in excess of the deadlines set in the technical documentation, the likelihood of loosening the tightening increases. This negatively affects the distribution of stresses in the power frame and, under unfavorable conditions, can lead to an increase in the level of mechanical stresses to critical values. The purpose of the work is a strain gauge method for monitoring the power frame of a hydraulic stamping press with threaded connections to assess the operability of the structure and conclude on the feasibility of repairs. Using strain gauges and finite element modeling methods, the regularities of the distribution of deformations in the material of columns and press racks with a maximum workload of 10 thousand tons are established. It is shown that in the working cycle, deformations are determined by the force and moment of force associated with the eccentricity of the application of the working force. Criteria for assessing the quality of threaded connections based on the relative difference and simultaneity of changes in mechanical stresses in the material of columns and press racks have been developed. The immobility of the connections of the power frame of the press during operation with maximum effort is ensured by the uniformity of the stress distribution on the racks and columns, taking into account the error of the results of the strain gauge method of 5%. The influence of the sliding elements of the movable elements of the press on the experimentally established patterns of stress distribution is substantiated by the method of finite element modeling.