Comparison of Direct Acoustic Impingement of Avionics Equipment to Vibration Base Shake Response
No abstract available
Scogin, Tyler M.↗
Engineering topics
LaVerde, Bruce T.
Publications and source records attributed to LaVerde, Bruce T..
Validation of Transmission Loss Simulation Approach with Goal to Estimate Launch Vehicle Internal Cavity Acoustics
No abstract available
Smith, Andrew M.↗
Resolution of Forces and Strain Measurements from an Acoustic Ground Test
The Conservatism in Typical Vibration Tests was Demonstrated: Vibration test at component level produced conservative force reactions by approximately a factor of 4 (approx.12 dB) as compared to the integrated acoustic test in 2 out of 3 axes. Reaction Forces Estimated at the Base of Equipment Using a Finite Element Based Method were Validated: FEM based estimate of interface forces may be adequate to guide development of vibration test criteria with less conservatism. Element Forces Estimated in Secondary Structure Struts were Validated: Finite element approach provided best estimate of axial strut forces in frequency range below 200 Hz where a rigid lumped mass assumption for the entire electronics box was valid. Models with enough fidelity to represent diminishing apparent mass of equipment are better suited for estimating force reactions across the frequency range. Forward Work: Demonstrate the reduction in conservatism provided by; Current force limited approach and an FEM guided approach. Validate proposed CMS approach to estimate coupled response from uncoupled system characteristics for vibroacoustics.
Smith, Andrew M.↗
Determining System Response using Uncoupled Transfer Functions - And Advantages Using Response Matching Methods
No abstract available
Smith, Andrew M.↗
Reporting Recommended Patch Density from Vehicle Panel Vibration Convergence Studies using both DAF and TBL Fits of the Spatial Correlation Function
Using the patch method to represent the continuous spatial correlation function of a phased pressure field over a structural surface is an approximation. The approximation approaches the continuous function as patches become smaller. Plotting comparisons of the approximation vs the continuous function may provide insight revealing: (1) For what patch size/density should the approximation be very good? (2) What the approximation looks like when it begins to break down? (3) What the approximation looks like when the patch size is grossly too large. Following these observations with a convergence study using one FEM may allow us to see the importance of patch density. We may develop insights that help us to predict sufficient patch density to provide adequate convergence for the intended purpose frequency range of interest
Smith, Andrew M.↗
Validation of Measured Damping Trends for Flight-Like Vehicle Panel/Equipment including a Range of Cable Harness Assemblies
This validation study examines the effect on vibroacoustic response resulting from the installation of cable bundles on a curved orthogrid panel. Of interest is the level of damping provided by the installation of the cable bundles and whether this damping could be potentially leveraged in launch vehicle design. The results of this test are compared with baseline acoustic response tests without cables. Damping estimates from the measured response data are made using a new software tool that leverages a finite element model of the panel in conjunction with advanced optimization techniques. While the full test series is not yet complete, the first configuration of cable bundles that was assessed effectively increased the viscous critical damping fraction of the system by as much as 0.02 in certain frequency ranges.
Smith, Andrew M.↗