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Support Tube Dynamic Analysis. KEK’s ANSYS simulation model details Single Point Response Spectrum analysis SUGGESTED improvements beam model Harmonic Response Analysis Random Analysis Transient Dynamic Analysis (time domain) . E. Doyle 12/6/99. KEK model constraints
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Support Tube Dynamic Analysis • KEK’s ANSYS simulation • model details • Single Point Response Spectrum analysis • SUGGESTED improvements • beam model • Harmonic Response Analysis • Random Analysis • Transient Dynamic Analysis (time domain) E. Doyle 12/6/99
KEK model constraints horiz rotations free, all other d.o.f. fixed
Four freq/displacement points used in KEK SPRS analysis - analysis of max response to transient event - damping accounted for in response curve
Beam Model - simply supported more efficient than shell model
Beam Model vs. Shell Model • Natural frequencies in Hz
Responses of Concern • Differential motion between Q1 magnets • Resulting from • non-uniform ground motion at two ends • structure asymmetry • ANSYS can be used to explore these • tube support dynamics • benefit from joining two cantilevers (creation of common modes)
Excitation Modes of Concern • Harmonic - cultural sources • Harmonic Response Analysis • Random - natural and cultural sources • Random PSD (power spectral density) • Transient Analysis (time domain)
Harmonic Analysis • Sinusoidal excitation at specified ampl & freq • Response at magnet mount points • Combine responses at all frequencies of interest
Harmonic analysis - vert base motion, unit amplitude Different damping for the two beams
Random Vibration Analysis • Input PSD of base motion • Result is PSD response at each magnet • how to interpret?
Absolute PSD Response ( 1m2/hz flat input) --------- FREQUENCY
PSD Response relative to base motion --------- FREQUENCY
Transient Dynamic Analysis • Input sampled ground motion (time domain) • Response is motion in time domain • Combine in time domain (outside ANSYS) • Generate cross correlation function (outside ANSYS)