Appendix M UML BUH Modal Testing
Peter Avitabile · 2017
UML BUH Modal TestingA generic academic structure has been used since 2000 at the University of Massachusetts Lowell in the Structural Dynamics and Acoustic Systems Laboratory.It is referred to as BUH (base-upright-horizontal). This structure has been tested in pieces and as an assembled structure; this structure has been used for many substructuring studies and various types of modal tests over the years.Correlations to finite element models have also been performed.A multiple reference impact test was performed with seven reference accelerometers mounted on the structure; 72 excitation points were used for impact.Figure M.1 shows the structure, with the components identified and measurement locations shown.Data was collected to 2000 Hz but only modes up to 325 Hz are evaluated here.The sum function in Figure M.2 shows many modes of this structure and the CMIF in Figure M.3 shows the same peaks with no apparent repeated roots.Figure M.4 shows the stability diagram, with 15 modes selected for modal extraction; the modes are shown in Figure M.5.Table M.1 shows the results of a correlation study with a finite element model.