Technology
Assessment & Research (TA&R) Program
| Project
Number |
23 |
| Date of Summary |
March 31, 1985 |
| Subject |
Incipient Structural Failure by
the Random Decrement Method |
| Performing Activity |
University of Maryland |
| Principal Investigator |
Dr. Jackson Yang |
| Contracting Agency |
Office of Naval Research |
| Estimated Completion |
Complete |
| Description |
This was a joint Industry Project
(JIP); to conduct a laboratory study of vibration response of a scale model of an offshore
tower subjected to random excitation. The random decrement technique will be applied to
the recorded and filtered vibration response data to establish a set of signatures. From
these signatures the sensitivity of the signatures to induced fatigue cracks of various
lengths and locations can be studied. |
| Progress |
Complete. Experimentation was
conducted on a model offshore structure which was tested in air and water and on solid and
sand footings. Effects of simulated structural damage were studied on natural frequency
and mode shapes. Results demonstrated the ability of the method to detect and measure
progressive failure in the model. The Random Decrement technique also was evaluated under
the NDE Round Robin Program, Project No. 34 and
results are encouraging. It is being applied to several offshore structures made available
by the Navy and the Coast Guard to determine possible field
related problems. |
| Reports |
AA (13 pages)
 |
Yang, J. C. S., Dagalakis, N. G.,
Hirt, M., Application of the Random Decrement Technique in the Detection of Induced Cracks
on an Offshore Platform Model, Computational Methods for Offshore Structures, Special
publication AMD-Volume 37 of the American Society of Mechanical Engineers (ASME). Library
of Congress #80-69180, 1980. |
| AB (24 pages)
|
Li, C. S., Yang, J. C. S.,
Dagalakis, N. G., Messick, W., Similitude Analysis and Testing of Prototype and 1:13.8
Scale Model of an Offshore Platform, This paper was accepted for publication in the 51st
Shock and Vibration Bulletin. |
| AC (5 pages)
|
Yang, J. C. S., Dagalakis, N. G.,
Detection of Incipient Failure in Structure Using Random Decrement Technique, Proceeding
of the Fall Meeting of Society of Experimental Stress Analysis (SESA), pp. 43, Ft.
Lauderdale, Florida, 1980. |
| AF (14 pages)
|
Yang, J. C. S., Aggour, M. S.,
Dagalakis, N., Miller, F., Damping of an Offshore Platform Model by Random Dec Methods,
American Society of Civil Engineers (ASCE)/EMD Specialty Conference, Atlanta, Georgia, pp.
819-832, January 15-16, 1981. |
| AJ (104 pages)
|
Lin, Chin-Po, The Measurement of
Damping and Natural Frequencies in Linear Systems by Using the Random Decrement Technique,
M. S. Thesis, University of Maryland, 1981. |
| AK (15 pages)
|
Miller, F. H., Dynamic Properties
of Offshore Structures with Different Foundation Types by the Random Decrement Technique,
M. S. Thesis, University of Maryland, 1981. |
| AL (11 pages)
|
Larach, E. R., Dynamic Response
and Safety of Offshore Platforms Using the Random Decrement Technique, M. S. Thesis,
University of Maryland, 1982. |
| AM (20 pages)
|
Felser, G. J., The Detection of
Fatigue Cracks in Offshore Structures Utilizing the Random Decrement Technique, M. S.
Thesis, University of Maryland, 1982. |
| AO (9 pages)
|
Yang, J. C. S., Aggour, M. S.,
Al-Sanad, H., Dynamic Shear Modulus and Damping from Random Loading Tests, ASTM
Geotechnical Testing Journal, Volume 6, No. 3, Philadelphia, Pennsylvania, September 1983. |
| AP (12 pages)
|
Yang, J. C. S., Dagalakis, N. G.,
Measurement of Structural Damping Using the Random Decrement Technique, The Shock and
Vibration Bulletin, Bulletin 53, Part 4, Naval Research Laboratory, Washington, D.C., May
1983. |
| AQ (9 pages)
|
Yang, J. C. S., Aggour, M. S.,
Al-Sanad, H., Application of the Random Decrement Technique in the Determination of
Damping of Soils, Proceedings of the Seventh European Conference on Earthquake
Engineering, Athens, Greece, September 1982. |
| AR (10 pages)
|
Yang, J. C. S., Tsai, T., Paulin,
V., Chen J., Tsai, W. H., Structural Damage Detection by the System Identification
Technique, 56th Shock and Vibration Bulletin, Dayton, Ohio, 1984. |
| AS (5 pages)
|
Yang, J. C. S., Marks, C. H.,
Jiang, J., Chen, D., Elahi, A., Tsai, W. H., Determination of Fluid Damping Using Random
Excitation, Third International Offshore Mechanics and Arctic Symposium, New Orleans,
Louisiana, February 12-17, 1983. |
| AT (10 pages)
|
Tsai, T., Yang, J. C. S. Chen, R.
F. Detection of Damages in Structures by the Cruss Random Decrement Method, Proceedings of
the 3rd International Model Analysis Conference, Orlando, Florida, pp. 691-700, January
28-31, 1985. |
| AU (9 pages)
|
Yang, J. C. S., Tsai, T., Tsai,
W. H., Chen, R. F., Detection and Identification of Structural Damage from Dynamic
Response Measurements, Fourth International Offshore Mechanics and Arctic Engineering
Symposium, OMAE, Dallas, Texas, February 17-21, 1985. |
| AV (83 pages)
|
Yang, J. C. S., Identification
and Location of Damages in Structures by the System Identification Technique, Progress
Report, University of Maryland, May 18, 1984. |
|
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