16810(16682) Engineering Design and Rapid Prototyping Lecture 7 a1n Structural Testing Instructor(s) Prof, olivier de weck January 21, 2004 Massachusetts Institute of Technology
(QJLQHHULQJ'HVLJQDQG5DSLG3URWRW\SLQJ (QJLQHHULQJ'HVLJQDQG5DSLG3URWRW\SLQJ /HFWXUH 6WUXFWXUDO7HVWLQJ ,QVWUXFWRU V 3URI2OLYLHUGH:HFN 3URI2OLYLHUGH:HFN -DQXDU\
IGa10 Outline Structural Testing Why testing is important Types of Sensors, procedures Mass, Static Displacement, Dynamics Test protocol for 16810 Explain protocol Sign up for time slots 16.810(16682) Massachusetts Institute of Technology
2XWOLQH 6WUXFWXUDO7HVWLQJ :K\WHVWLQJLVLPSRUWDQW 7\SHVRI6HQVRUV3URFHGXUHV« 0DVV6WDWLF'LVSODFHPHQW'\QDPLFV 7HVW3URWRFROIRU ([SODLQSURWRFRO 6LJQXSIRUWLPHVORWV
Data Acquisition and Processing al0 for Structural Testing (1)Sensor Overview Accelerometers, Laser sensors, Strain Gages Force Transducers and load cells gyroscopes (2)Sensor Characteristics Dynamics FRF of sensors, bandwidth resolution placement issues (3)Data Acquistion Process Excitation Sources, Non-linearity, Anti-Alias Filtering, Signal Conditioning (4)Data Post-Processing FFT, DFT, Computing PSD's and amplitude spectra statistical values of a signal such as rms, covariance etc (5)Introduction to System Identification ETFE, DynaMod measurement models 16.810(16682) Massachusetts Institute of Technology
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
IGAl0 Why is Structural Testing Important? M Example: Ground vibration Testing Product Qualification Testing Performance assessment a System Identification Design verification Damage assessment Aerodynamic Flutter Testing Operational Monitoring Material Fatigue Testing stimulus A Structural response Ref:http://www.af.mil/photos/may1999/19990518f2235.html System (imAgeistakenfromU.s.AirForceWebsitehttp://www.af.mill) vibration tests at edwards air N DAQ H DSP Force Base, calif. in april 1999 DAQ=data acquisition DSP =digital signal processing 16.810(16682) Massachusetts Institute of Technology
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mage is taken from U.S. Air Force Web site: http://www.af.mil.)
IGA10 I. Sensor Overview This sensor morphology is useful for classific of typical sensors used in structural dynamics Sensor Morphology Table Type Linear Rotational Bandwidth Low Medium High DerivativePosition Rate Acceleration Reference Absolute Relative Quantity Force/Torque Displacement Impedance Low High Example: uniaxial strain gage Need units of measurement [m], [Nml[)[rad]etc 16.810(16682) Massachusetts Institute of Technology
,6HQVRU2YHUYLHZ 7KLV6HQVRUPRUSKRORJ\LVXVHIXOIRUFODVVLILFDWLRQ RIW\SLFDOVHQVRUVXVHGLQVWUXFWXUDOG\QDPLFV 6HQVRU0RUSKRORJ\7DEOH 6HQVRU0RUSKRORJ\7DEOH 7\SH %DQGZLGWK 'HULYDWLYH 5HIHUHQFH 4XDQWLW\ ,PSHGDQFH /LQHDU 5RWDWLRQDO /RZ 0HGLXP +LJK 3RVLWLRQ 5DWH $FFHOHUDWLRQ $EVROXWH 5HODWLYH )RUFH7RUTXH 'LVSODFHPHQW /RZ +LJK ([DPSOH XQLD[LDOVWUDLQJDJH 1HHGXQLWVRIPHDVXUHPHQW >P@>1P@> µVWUDLQ@>UDG@HWF«