1. Ae105c CDR, June 3, 2009 p. 1 Ae105c Term Project CDR Team report from Experimental Team Jason Cerundolo Vivek Viswanathan Pelayo Bohorquez

2. Ae105c CDR, June 3, 2009 p. 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. Ae105c CDR, June 3, 2009 p. 3 Interfaces Will be put into master matrix in appropriate spots.

4. Ae105c CDR, June 3, 2009 p. 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. Ae105c CDR, June 3, 2009 p. 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. Ae105c CDR, June 3, 2009 p. 6 Disposition of RFAs RFA / ConcernRecommendationAction Taken #2: Address resolution of measurements Look at specs for lasers and requirement for precision Measurements from lasers are accurate to about 1 μm. Precision required by other teams was not specified and assumed to be sufficient. #6: Interfaces not aligned Teams meet to scrub interfaces Met with teams, specifically System ID and Structural, and clarified experiments to be completed. #7: Level 1,2 requirements not set Specify level 1 and 2 requirements Met as a class and determined level 1 and 2 requirements for each team.

7. Ae105c CDR, June 3, 2009 p. 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. Ae105c CDR, June 3, 2009 p. 8 8 Technical Status  All testing and publishing is completed.  Experimental results have met or exceeded the requirements of the other teams.

9. Ae105c CDR, June 3, 2009 p. 9 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 displacemen t for a given input voltage using feedback. – A load cell measures the force applied by the shaker. – Low load cell measuremen ts 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.

10. Ae105c CDR, June 3, 2009 p. 10 10 General Experimental Setup 

11. Ae105c CDR, June 3, 2009 p. 11 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.

12. Ae105c CDR, June 3, 2009 p. 12 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.

13. Ae105c CDR, June 3, 2009 p. 13 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.

14. Ae105c CDR, June 3, 2009 p. 14 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.

15. Ae105c CDR, June 3, 2009 p. 15 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.

16. Ae105c CDR, June 3, 2009 p. 16 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.

17. Ae105c CDR, June 3, 2009 p. 17 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

18. Ae105c CDR, June 3, 2009 p. 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. Ae105c CDR, June 3, 2009 p. 19 Back-up Material

20. Ae105c CDR, June 3, 2009 p. 20 Equipment Used Equipment Manufacture r ModelNotes Laser HeadKeyence LK-G157 & LK- G87 Displacement sensor Laser ControllerKeyenceLK-GD500 Signal GeneratorAgilent33250A Generate input signal for force shaker Power AmplifierLabworks Inc.PA-138 Force SensorPCB208C01a.k.a. “Load Cell” Vibration MotorLabworks Inc.ET-132a.k.a. “Shaker” Signal Conditioner PCB480E09 Analog to Digital Converter National Instruments NI USB-6210 Data Collection Program National Instruments LabView 8.6 Running on Windows Vista Post ProcessingMATLab2009b Running on various operating systems