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

Ae105c CDR, June 3, 2009 p. 2 Experimental Level 2 Requirements Provide experimental data, including geometry, material property, static, and dynamic data, used to verify a structural finite element model (FEM).

Ae105c CDR, June 3, 2009 p. 3 Group Interfacing ExperimentalSystem IDStructuralDynamics Experimental Statics & dynamics test data Experimental setup descriptions Voltage to displacements/acceleration conversions Experimental data in engineering units Experimental parameters used Mass & Geometry Material Properties Test Specifications System ID Deadlines to meet Experiments to perform Test parameters Test procedures Damping Coefficients Natural Frequencies Static Results Modal shapes (for correlation) Frequencies Damping Static and dynamic result Structural Experiments to run Requests for properties to be measured Theoretical model containing the modes of the dynamical system Modal Properties (mass, length, etc.) Dynamics System Performance  project level

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.  Battens are always in compression.  Diagonals always in tension.  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. Longeron Batten Diagonal

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.

Ae105c CDR, June 3, 2009 p. 6 Disposition of RFAs InitiatorConcernRecommendationAction Marco Address resolution of measurements Look at spec of lasers and precision required Laser precision around 1 μm and confirmed to be sufficient by other teams.

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  Torsion Test  Experimental descriptions, parameters, and data posted online and linked to from the wiki.

Ae105c CDR, June 3, 2009 p. 8 Technical Status  All testing and publishing is completed.  Experimental results have correlated with theoretical predictions.  Special thanks to Case Branford for help in the lab.

Ae105c CDR, June 3, 2009 p. 9 General Experimental Setup  Canister firmly mounted on pipe structure with ratcheted 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. MiddleRootCanister Side Tip Side Root Tip Force Shaker Load Cell

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

Ae105c CDR, June 3, 2009 p. 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. Canister Root Middle Tip Displacement [mm] Force [N] Displacement [mm] Plot courtesy of Case Bradford Time

Ae105c CDR, June 3, 2009 p. 12 Sine Sweep Test Shaker is given sine wave input swept through a frequency range (5 – 100 Hz). Time scale was logarithmic and approximately 1 octave/minute. FFT of displacement over FFT of load cell data shows modes of vibration. Modes found near 11 & 14 Hz. Frequency [Hz] Intensity ratio displacement/force

Ae105c CDR, June 3, 2009 p. 13 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. Time [s] 16 Displacement [mm]

Ae105c CDR, June 3, 2009 p. 14 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 52 Hz. Root Same Side of Load Tip Opposite Side of Load Root Opposite Side of Load Tip Same Side of Load Force Shaker Load Cell Plot goes here

Ae105c CDR, June 3, 2009 p. 15 Open Issues and Concerns  Random noise test has insufficient signal-to-noise ratio. – Replaced 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 100 Hz.  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

Ae105c CDR, June 3, 2009 p. 16 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 Low signal-to-noise ratio. Sine sweep Chosen over random noise due to higher signal-to-noise ratio. Used by System ID Team to correlate modes with computerized models. 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.

Ae105c CDR, June 3, 2009 p. 17 Back-up Material

Ae105c CDR, June 3, 2009 p. 18 Equipment Used EquipmentManufacturerModelNotes 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

Ae105c CDR, June 3, 2009 p. 19 Material Property Experiments Diagonal Tension Test Batten Compression Test Batten Tension Test

Ae105c CDR, June 3, 2009 p. 20 Material Property Measurements Diagonals: cylindrical cross section Battens: rounded rectangle cross section PropertyValue [Units]Method Length24.9 cmRuler Diameter1.25 mmCalibers Mass1.2 gScale Young’s Modulus48.97 GPaTensile Test PropertyValue [Units]Method Length (uncompressed)18.1 cmRuler Width2.87 mmCalibers Depth3.77 mmCalibers Mass (batten unit)14.2 gScale Young’s ModulusTDBTensile Test

Ae105c CDR, June 3, 2009 p. 21 Static Test Setup 4 Laser displacement sensors DAQ unit collects data at 100 Hz Weights added to the tip Fixed boundary condition created with two tie-down straps Tip

Ae105c CDR, June 3, 2009 p. 22 Static Test Results Time Displacement Time Tip Canister Root Middle Tip Middle Canister Root Canister Root Middle Tip

Ae105c CDR, June 3, 2009 p. 23 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.

Ae105c CDR, June 3, 2009 p. 24 Random Vibration Test Shaker is given random noise from function generator. Test was unsuccessful – 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.