Revamp of supporting surfaces of turbogenerating sets foundation frames by composite materials

Structural mechanics

Paper shows results of experimental studies of loading capacity of composite material ‘Multimetal Stahl 1018’ under static and vibrational loads at high temperatures in order to possibly use this material as a leveling layer on supporting surfaces of large-sized units of turbogenerating sets when they are mounted on foundation frames. Tensile strengths of composite samples were obtained at static loading for temperature range +20°С...+80°С on experimental machine ‘РМ-20’; obtained values do not exceed the maximum compressive stress of the material σ = 160 MPa. Experimental studies have been conducted on a specially created vibration unit because construction of foundation of turbogenerating sets is subjected to vibrations with wide spectrum of frequencies. Parameters of oscillatory process were measured using vibration velocity meter, signals were fixed using ADC ‘Е 14-140M’ and amplifier ‘LE-41’; signals processing was performed on ‘DSP’ processor module. Differential equation of forced oscillations is compiled, amplitudes and dynamics coefficients are determined for constructed dynamic model of vibration unit. Dependence of oscillation amplitude on height of the test samples is presented graphically. Table summarizes values of the dynamic coefficients at different samples heights for the same temperature spectrum as in case of static loads. It was concluded that the dynamic coefficient decreases with increasing temperature for larger height of sample. It was experimentally established that studied composite material withstands dynamic loads significantly exceeding those that can occur when installing turbogenerating sets on foundation frames. This allowed to recommend material ‘Multimetal Stahl 1018’ for use in installation of turbogenerating sets. Technology has been proposed for revamp of supporting surface of foundation frame in order to perform such works. Industrial tests that were carried out at two thermal power plants when revamping supporting surfaces of foundation frames under turbogenerating set ‘TGV 200’ and under low pressure cylinder of turbine ‘К-20-180 LMP’ that confirmed effectiveness of proposed method and its operability.