h integrated dial thermometer FSAT H Oil level in B4-FV22-B Bevel-helical speed reducers B4

Flender/Flender Gear Units/Bevel-helical speed reducers B4

ysis. As in the frequency response measurement, stochastic excitation signals ranging from 0 Hz to 1,0 Hz are generally employed. The displacements in the machine are mea- sured by accelerometers at each of the measuring points, preferably in the coordi- nate directions, and are related to the applied forces. The transfer functions determined in this manner are then interpreted in terms of amplitude peaks and phase positions in the range of dominant resonant frequencies extracted from the compliance frequency responses [ EWIN0 ]. Fig. 8.7 Compliance measurement on dressing spindle ( left) and three-dimensional measuring set-up for modal analysis3 8 Dynamics of Machine Tools Determination of the transfer functions for each point in the structure is followed by curve tting [ KIRC8 ] in which the measured transfer functions are described mathematically. In this approximation of the transfer functions through complex analytical equations, the frequency and the damping are required for each important resonant frequency mode, each point in the structure and each direction of thecomplex compliance vector. There are many different curve processes, generallydistinguished into two categories, [ NATK9 ]: single degree of freedom (SDOF) processes and multiple degree of freedom (MDOF) processes In the SDOF process, the structure is described by system of decoupled single mass oscillators with single degree of freedom, .. the mode is determined as if this were the only resonant frequency of the structure. The cumulative compliancefrequency response of the structure can then be described as the sum of allindividual frequency responses. It should be pointed out that the individual vibra-tion modes of the tested structure must be clearly decoupled if the SDOF method isused. This is manifested in the compliance frequency responses by individualresonance points which are well separated in terms of their frequencies, andhence have only slight inuence on each other. SDOF processe