Mechanical analysis on beryllium rotating mirror of ultra-high speed camera

The methods of numerical analysis for the strength and modal of rotating mirrors were presented based respectively on the three-dimensional elastic mechanics and dynamics.On strength computation,the finite element models of rotating mirror were established according to the real structure of the mirror,and the rotating three-faced beryllium mirror were analysed.Results display that the surface deformation magnitude of the mirror is approximately 0.334 6 μm,and the maximum stress is 0.204 GPa at 600 m/s of edge linear speeed.The regions of maximum stress are on the axial hole and symmetric to symmetrical planes of mirror body,and keep beelines to surfaces.On the modal analysis,the results show that the first and second modals of bending vibration exist around 3.4×105 r/min and 6.6×105 r/min,which appear binate and orthogonal respectively,and another modal belongs to the first torsional vibration that occurs by 5.13×105 r/min.Analysis indicates that endurance failure by resonances plays vital role for mirror failure rather than static load by body force if manufacturing defects are of nonexistence.