Abstract
The Dynamic Inertia Measurement (DIM) method uses a ground vibration test setup to determine the mass properties of an object using information from frequency response functions. Most conventional mass properties testing involves using spin tables or pendulum-based swing tests, which for large aerospace vehicles becomes increasingly difficult and time-consuming, and therefore expensive, to perform. The DIM method has been validated on small test articles but has not been successfully proven on large aerospace vehicles. In response, the National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) conducted mass properties testing on an “iron bird” test article that is comparable in mass and scale to a fighter-type aircraft. The simple two-I-beam design of the “iron bird” was selected to ensure accurate analytical mass properties. Traditional swing testing was also performed to compare the level of effort, amount of resources, and quality of data with the DIM method. The DIM test showed favorable results for the center of gravity and moments of inertia; however, the products of inertia showed disagreement with analytical predictions.
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Abbreviations
- AFRC:
-
Armstrong Flight Research Center
- CAD:
-
Computer-aided design
- CG:
-
Center of gravity
- CRV:
-
Crew return vehicle
- DFRC:
-
Dryden Flight Research Center
- diff:
-
Difference
- DIM:
-
Dynamic inertia measurement
- DOF:
-
Degree of freedom
- ETA:
-
Engineering test article
- F:
-
Force
- FRF:
-
Frequency response function
- Fx :
-
Force in x-axis
- Fy :
-
Force in y-axis
- Fz :
-
Force in z-axis
- g:
-
Gravitational acceleration
- GVT:
-
Ground vibration test
- Hz:
-
Hertz
- I:
-
Inertia matrix
- IMAT:
-
Interface between MATLAB® Analysis, and Test
- Ixx :
-
Moment of inertia about the x-axis
- Ixy :
-
Product of inertia between x and y-axis
- Ixz :
-
Product of inertia between x and z-axis
- Iyy :
-
Moment of inertia about the y-axis
- Iyz :
-
Product of inertia between y and z-axis
- Izz :
-
Moment of inertia about the z-axis
- Ixz :
-
Moment of inertia about the xz-axis
- L:
-
Length
- m:
-
Mass
- M:
-
Mass matrix
- MOI:
-
Moment of inertia
- NACA:
-
National Advisory Committee for Aeronautics
- NASA:
-
National Aeronautics and Space Administration
- Nx :
-
Moment about the x-axis
- Ny :
-
Moment about the y-axis
- Nz :
-
Moment about the z-axis
- POI:
-
Product of inertia
- PSMIF:
-
Power spectrum mode indicator function
- T:
-
Period
- w:
-
Weight
- x:
-
Time or frequency
- \( \ddot{\mathrm{x}} \) :
-
Linear acceleration in x-axis
- XCG :
-
Center of gravity location along the x-axis
- YCG :
-
Center of gravity location along the y-axis
- ZCG :
-
Center of gravity location along the z-axis
- ÿ:
-
Linear acceleration in y-axis
- \( \ddot{\mathrm{z}} \) :
-
Linear acceleration in z-axis
- \( \ddot{\uptheta} \) :
-
Angular acceleration
- \( {\ddot{\uptheta}}_{\mathrm{x}} \) :
-
Angular acceleration about x-axis
- \( {\ddot{\uptheta}}_{\mathrm{y}} \) :
-
Angular acceleration about y-axis
- \( {\ddot{\uptheta}}_{\mathrm{z}} \) :
-
Angular acceleration about z-axis
- 60K3S:
-
60,000-lb Starr Soft Support
References
Toivola J, Nuutila O (1993) Comparison of three methods for determining rigid body inertia properties from frequency response functions. In: Proceedings of the 11th international modal analysis conference, Kissimmee, pp 112–1132
Witter MC,(2000) Rigid body inertia property estimation using the dynamic inertia method. Master of Science thesis, Department of Mechanical Engineering, University of Cincinnati
Lazor DR (2004) Considerations for using the dynamic inertia method in estimating rigid body inertia property. Master’s of Science thesis, Department of Mechanical Engineering, University of Cincinnati
Peterson WL (2004) Mass properties measurement in the X-38 project. SAWE paper no. 3325, category 6.
Stebbins MA, Brown DL (1998) Rigid body inertia property estimation using a six-axis load cell. In: Proceedings of the 16th international modal analysis conference, Santa Barbara, pp 900–906
Gatzwiller KB, WitterMC, Brown DL (2000) A new method for measuring inertial properties. In: Proceedings of the 18th international modal analysis conference, San Antonio, pp 1056–1062
Witter MC, Brown DL, Dillon M (1999) A new method for RBP estimation – the dynamic inertia method. SAWE paper no. 2461, category no. 6
Green MW (1927) Measurement of the moments of inertia of full scale airplanes. NACA Technical Note No. 265
Miller MP (1930) An accurate method of measuring the moments of inertia of airplanes. NACA Technical Note No. 351
Miller MP, Soule HA (1931) Moments of inertia of several airplanes. NACA Technical Note No. 375
Soule HA, Miller MP (1933) The experimental determination of the moments of inertia of airplanes. NACA Report No. 467
Turner HL (1950) Measurement of the moments of inertia of an airplane by a simplified method. NACA Technical Note 2201
Gracey W (1941) The additional-mass effect of plates as determined by experiments. NACA Report No. 707
Fladung WA, Napolitano KL, Brillhart RD (2010) Final report on dynamic inertia measurement method testing, unpublished internal document. ATA Engineering, San Diego
Cloutier D, Fladung WA (2013) Final report on dynamic inertia measurement method testing on iron bird 2, unpublished internal document. ATA Engineering, San Diego
Holland JA (2014) A safe, advanced, adaptable isolation system that eliminates the need for critical lifts. NP-2009-08-02-DFRC, http://www.nasa.gov/pdf/484129main_Soft-Support-TOP.pdf. Accessed 30 Oct 2014
Acknowledgements
The authors thank the NASA Aeronautics Research Mission Directorate Aerosciences Project and Aeronautics Test Program for funding the Dynamic Inertia Measurement research. The authors also thank the testing support personnel at the Flight Loads Laboratory at the Armstrong Flight Research Center for conducting the Dynamic Inertia Measurement and pendulum tests. Special thanks also go to aerospace engineers Bob Clarke and Adam Harding of the Armstrong Flight Research Center for their support and expertise in performing the conventional pendulum mass properties tests.
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Chin, A.W., Herrera, C.Y., Spivey, N.D., Fladung, W.A., Cloutier, D. (2015). Testing and Validation of the Dynamic Inertia Measurement Method. In: Wicks, A. (eds) Shock & Vibration, Aircraft/Aerospace, and Energy Harvesting, Volume 9. Conference Proceedings of the Society for Experimental Mechanics Series. Springer, Cham. https://doi.org/10.1007/978-3-319-15233-2_10
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DOI: https://doi.org/10.1007/978-3-319-15233-2_10
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