1 / 20

Ae105c Term Project CDR Team report from Experimental Team Jason Cerundolo

Ae105c Term Project CDR Team report from Experimental Team Jason Cerundolo Vivek Viswanathan Pelayo Bohorquez. Level 2 Requirements. Level 2 – Experimental Team Specific

Download Presentation

Ae105c Term Project CDR Team report from Experimental Team Jason Cerundolo

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Ae105c Term ProjectCDRTeam report from Experimental Team Jason Cerundolo Vivek Viswanathan Pelayo Bohorquez

  2. Level 2 Requirements • Level 2 – Experimental Team Specific • Provide experimental data, including geometry, material property, static, and dynamic data, used to verify a structural finite element model (FEM).

  3. Interfaces • Will be put into master matrix in appropriate spots.

  4. Assumptions • All tests must be non-destructive. • Filters on hardware electronics do not affect data in region of interest. • Verified by manufacturers' datasheets. The filter cut-off frequency is much higher than region of interest. • Motion of boundary condition is negligible. • Valid assumption because motion of canister during testing was below the noise floor. • The boom's response is in the linear stress-strain region. • This is driven by the System ID and Structural teams' models and influences experiments that are run and the processing of the data.

  5. Synopsis up to PDR • Geometry and material properties measurements were completed and published. • Static test were completed and in process of being published and processed. • Brainstormed ideas for dynamic testing

  6. Disposition of RFAs

  7. Progress Since PDR • Static test parameters have been published • Dynamic testing completed • Random vibration • Sine sweep • Tap Test • Ambient Test • Torsion Test • Experimental descriptions, parameters, and data posted online and linked to from the wiki.

  8. Technical Status • All testing and publishing is completed. • Experimental results have met or exceeded the requirements of the other teams. 8

  9. General Experimental Setup • Canister firmly mounted on pipe structure with racketed tie-down straps. • Laser displacement sensors measure vertical and horizontal displacement. • Shaker is attached to center of endplate. • The shaker moves a given displacement for a given input voltage using feedback. • A load cell measures the force applied by the shaker. • Low load cell measurements imply modes. • Signals from sensors are processed by input boxes and captured on a PC running LabView under Windows Vista. • Tests run multiple times to ensure repeatability. 9

  10. General Experimental Setup 10

  11. Static Force-Displacement Test • Known masses were hung by the center of the end plate. • Deflection of the boom at multiple points was measured. • Force-displacement curve could be fit to stiffness. 11

  12. Random Vibration Test • Shaker is given random noise from function generator. • Data was not used in analysis • The function generator excited up through 50 MHz. • Region of interest was 1 – 100 Hz, only a small amount of energy was exciting those frequencies. • This resulted in an insufficient signal-to-noise ratio. 12

  13. Sine Sweep Test • Shaker is sine wave input swept through a frequency range (5 – 100 Hz). • Time scale was logarithmic and around 4 octaves/minute. • FFT of displacement over FFT of load cell data show modes of vibration. • Mode found near 15 Hz. 13

  14. Tap Test • Structure is excited by a manual tap with a hammer. • The ring down response is measured. • Allows easy calculation of damping. • Ideally shows fundamental mode. 14

  15. Ambient Test • Structure is left undisturbed and response measured. • This test gives a good indication of the noises environment in the lab. • Can identify unexpected modes and identify regions of noise. 15

  16. Torsion Test • Shaker was mounted off-axis and connected to one of the longerons not on the vertical axis of symmetry • Lasers were positioned off-axis. • Difference in position is the torsion. • Mode found near 50 Hz. 16

  17. Open Issues and Concerns • Random noise test has insufficient signal-to-noise ratio. • FFT of ambient matched random noise. • Compensated by sine sweep testing. • Recommend a narrow band-limited function generator to supply random noise in the future. • Current set up is limited to 50 MHz. • Region of interest is only up to 1 kHz. • Test Conducted with imperfect boundary condition. • Recommend detailed study of canister mount be conducted in the future. • Recommend a more isolating mount be used. • Tap Test • Force hammer would provide more data and allow for another check of results. • For now, only good for damping 17

  18. Summary • Testing specified by level 2 requirements is complete. • Geometry and material property • Provided at sufficient fidelity to Structural Team • Static • Force-displacement • Used to correlate with Structural Team's model. • Dynamic • Random vibration • Used to identify regions of interest and rough estimates of mode frequencies. • Sine sweep • Chosen over random noise due to higher signal-to-noise ratio. • Used by System ID Team to correlate modes with computerized models. • Ambient noise • Used by System ID Team to remove lab environment noise from other tests. • Improved fidelity of data from other dynamic tests. • Tap response • Used by System ID Team to deduce damping response. • Torsion • Used by System ID Team to identify torsional modes and correlate with computerized models.

  19. Back-up Material

  20. Equipment Used

More Related