Structural Health Monitoring of Steel Frame Structure by Experimental Modal Parameter Identification

Abstract:

Structural health monitoring (SHM) is a modern technique for damage identification in the existing structure. The structural stiffness, frequency, damping, and dominant mode shapes represent the actual operating conditions of the structure. The main principle of structural health monitoring is to identify the modal parameters from experimental results both damaged and undamaged conditions. Damage is much effective to decrease stiffness and strength of structural components and it changes dynamic behaviour and damping ratio of whole structures. Bruel & Kjaer experimental modal analysis technique is recently used for civil engineering structures for modal parameters estimation. The paper describes the initial structural health monitoring of a steel frame. The modal parameters were estimated for undamaged conditions and these results are verified and updated by the numerical FEM tool SAP2000. For the undamaged structure, mode shapes and frequencies were calibrated properly. In the second step, damaged was initiated by dismantling one element from the lower part of the frame. The estimated modal parameters were compared to the initial one. The mode shapes and frequencies are quite different for some specific mode due to damage initiation. One extra mode was created for the damaged frame due to damage initiation. The 4^th mode was not found for the initial measurement because of presence of lower beam. Lower beam restraints the 4^th mode and the frame behaves more flexible. Keywords: SHM, Modal parameters, FEM modelling, Damage characterization, Experimental modal analysis (EMA).

• Periodical: Advanced Engineering Forum (Volume 37)
• Pages: 1-13
• DOI: https://doi.org/10.4028/www.scientific.net/AEF.37.1
• Online since: September 2020
• Authors: Bulbul Ahmed*, Florea Dinu, Ioan Marginean
• Keywords: Damage Characterization, Experimental Modal Analysis (EMA), FEM Modelling, Modal Parameters, SHM

References

[1] A. Aktan, J. Brownjohn, Structural identification: opportunities and challenges, Journal of Structural Engineering 139(2013) 1639-47.

DOI: 10.1061/(asce)st.1943-541x.0000723

[2] Wei-Xin Rena, P. Xue-Lin, L. You-Qin, Experimental and analytical studies on dynamic characteristics of a large span cable-stayed bridge, Engineering Structures 27 (2005) 535-548.

DOI: 10.1016/j.engstruct.2004.11.013

[3] W. M. West, Illustration of the use of modal assurance criterion to detect structural changes in an orbiter test specimen, in: Proceeding Air Force Conference on Air Craft Structural Integrity, 11(1984), 1-6.

[4] E. Peter Carden, M.W. James Brownjohn, ARMA modelled time-series classification for structural health monitoring of civil infrastructure; Mechanical Systems and Signal Processing 22 (2008) 295-314.

DOI: 10.1016/j.ymssp.2007.07.003

[5] L. Deng, C. Cai, Bridge model updating using response surface method and genetic algorithm. Journal of Bridge Engineering 15 (2009) 553-64.

DOI: 10.1061/(asce)be.1943-5592.0000092

[6] Bruel & Kjaer manual for experimental modal analysis. Available: https://www.bksv.com/en/Applications/product-vibration/structural-dynamics.

[7] F. Dinu, Experimental validation of the response of a building in frames subjected to explosion action - FRAMEBLAST,, 2017-2018.

[8] Bruel & Kjaer manual for experimental modal analysis. https://www.bksv.com.

[9] F. Çatbaş, T. Kijewski-Correa and A. Aktan, Structural identification of constructed systems: Approaches, methods, and technologies for effective practice of St-Id, ASCE, Reston, Vibration Analysis, J. Struct. Eng. 139(2013) 1648-52.

DOI: 10.1061/9780784411971

[10] Gaetan Kerschen - Jean-Claude Golinval; Experimental Modal Analysis.

[11] K. L. Lawrence, ANSYS tutorial: structural and thermal analysis using the ANSYS mechanical APDL release 13 environments. Schroff Development Corporation (SDC) publications (2011).

[12] M. Hassan Haeri, M. Alireza Lotfi, Kiarash Dolatshahi, A. A. Golafshani, Inverse vibration technique for structural health monitoring of offshore jacket platforms, Applied Ocean Research 62 (2017) 181-198.

DOI: 10.1016/j.apor.2016.11.010

[13] P. I. Kattan, MATLAB guide to finite elements: an interactive approach. Springer (2010).

[14] P. Moradipour, H.T. Tommy Chan, C. Gallage, Benchmark studies for bridge health monitoring using an improved modal strain energy method; 6th Asia Pacific Workshop on Structural Health Monitoring, 6th APWSHM; Procedia Engineering 188 (2017) 194-200.

DOI: 10.1016/j.proeng.2017.04.474

[15] T. Kernicky, Matthew Whelan, Usman Rauf, Ehab Al-Shaer, Structural identification using a nonlinear constraint satisfaction processor with interval arithmetic and contractor programming; Computers and Structures 188 (2017) 1-16.

DOI: 10.1016/j.compstruc.2017.04.001

[16] Wei-Xin Ren and Zhou-Hong Zong, Output-only modal parameter identification of civil engineering structures, Structural Engineering and Mechanics, 17(3-4) (2004) 000-000.

DOI: 10.12989/sem.2004.17.3_4.429