Experimental studies of shell vibrations

Results of modal analysis by ANSYS software for high pressure shaft of turbofan engine NK-8 are presented. Results of experimental researches of low modes and frequencies of the shell by photogrammetric complex ARAMIS HS are given as verification of calculations. The main attention is for experiment fulfillmentfeatures. For example, conditions of shell installation for free position of shaft are developed; different ways of researched shell vibration excitement are used. It gives a possibility of correct experiment for own frequencies obtaining. Comparison experiments for different values of crop-factor are fulfilled; analysis of information volume for obtained pictures is undertaken. Technology of researched object lighting for satisfactory image recognition for little exposure is developed. Methods of researched object photographing for complex algorithm of pictures switching are developed. It gives a possibility of experimental research of vibration processes which frequency is more than limit frequency of recording equipment. By these results an experimental methodic is developed and an experiment is fulfilled. First and second own frequencies are obtained experimentally; its values correspond to calculation results. In means that modeling of shaft in ANSYS software and boundary conditions are correct. Vibration modes for frequencies 211 Hz and 362 Hz are obtained. It corresponds to calculation results too. This research is fulfilled as a part of research of high pressure shaft of turbofan engine NK-8, as obtaining of correct model of boundary conditions (stiffness and damping of flange connection between shaft and disks of turbine and compressor) and influence of these boundary conditions on own frequencies and modes.