The Effectiveness of Operational Modal Analysis (OMA) for Detecting Saw Cut Damage in Fiberglass Reinforced Epoxy

2013 ◽  
Vol 393 ◽  
pp. 649-654
Author(s):  
Haizuan Abd Rahman ◽  
Ahmad Azlan Mat Isa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Material ◽  
Damage Detection ◽  
Modal Analysis ◽  
Detection Method ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Fiber Glass ◽  
Element Method

This study attempts to apply vibration based damage detection method specifically operational modal analysis (OMA) on fiberglass reinforced epoxy plate. OMA is used on undamaged fiber glass reinforced epoxy plate to extract the modal parameters and after which the procedure is extended to saw cut damage fiberglass reinforced epoxy plate. Both healthy and damaged composite material are tested for different boundary conditions i.e. free-free on 4 edges, 1 edge clamped, 2 edges clamped, 3 edges clamped and 4 edges clamped condition. Then result of frequency from OMA was compared analytically with finite element method. Based on the results, it shows that a high deviation between OMA and finite element method can be observed. Result of frequency from OMA was then compared with Experimental Modal Analysis (EMA) to validate the effectiveness of OMA method. It is shown that results obtained from OMA are in good correlation with results obtained from EMA.

EFFECTIVENESS OF OPERATIONAL MODAL ANALYSIS (OMA) FOR DAMAGE DETECTION IN FIBERGLASS REINFORCED EPOXY

2015 ◽  
Vol 76 (8) ◽  
Author(s):  
Haizuan Abd Rahman ◽  
Ahmad Azlan Mat Isa ◽  
Abdul Rahim Bahari
Keyword(s):  
Finite Element Method ◽  
Boundary Condition ◽  
Composite Material ◽  
Damage Detection ◽  
Modal Analysis ◽  
Detection Method ◽  
Small Deviation ◽  
Operational Modal Analysis ◽  
Modal Parameters ◽  
Fiber Glass

This study attempts to apply vibration-based damage detection method specifically Operational Modal Analysis (OMA) on fiberglass reinforced epoxy plate. OMA is used on healthy fiber glass reinforced epoxy plate to extract the modal parameters and the procedure is extended to damaged fiberglass reinforced epoxy plate. Both healthy and damaged composite material are tested under different boundary conditions i.e. free-free on 4 edges, 1 edge clamped, 2 edges clamped, 3 edges clamped and 4 edges of free-free boundary condition. The result of frequency from OMA was compared analytically with Finite Element Method (FEM). Nastran software is employed in this study. The FEM using Nastran shows that the result obtained is not accurate enough compared to OMA. Therefore, another method was applied to look at the effectiveness of OMA method using Experimental Modal Analysis (EMA). It was observed that both EMA and OMA methods gave small deviation and good correlation.

Damage detection based on system identification of concrete dams using an extended finite element–wavelet transform coupled procedure

2017 ◽  
Vol 24 (18) ◽  
pp. 4226-4246 ◽  
Author(s):  
Sajjad Pirboudaghi ◽  
Reza Tarinejad ◽  
Mohammad Taghi Alami
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Wavelet Transform ◽  
System Identification ◽  
Damage Detection ◽  
Cohesive Crack ◽  
Modal Parameters ◽  
Concrete Dams ◽  
Extended Finite Element ◽  
Element Method

The aim of the present study is to propose a procedure for seismic cracking identification of concrete dams using a coupling of the extended finite element method (XFEM) based on cohesive crack segments (XFEM-COH) and continuous wavelet transform (CWT). First, the dam is numerically modeled using the traditional finite element method (FEM). Then, cracking capability is added to the dam structure by applying the XFEM-COH for concrete material. The results of both the methods under the seismic excitation have been compared and identified to damage detection purposes. In spite of predefined damage in some of the structural health monitoring (SHM) techniques, there is an advantage in the XFEM model where the whole dam structure is potentially under damage risk without initial crack, and may not crack at all. Finally, in order to evaluate any change in the system, that is, specification of any probable crack effects and nonlinear behavior, the structural modal parameters and their variation have been investigated using system identification based on the CWT. The results show that the extended finite element–wavelet transform procedure has high ability for the online SHM of concrete dams that by analysis of its results, the history of physical changes, cracking initiation time, and exact damage localization have been performed from comparing the intact (FEM) and damaged (XFEM) modal parameters of the structural response. In addition, any small change in the system is observable while the final crack profile and performance simulation of the dam body under strong seismic excitations have obtained.

ANSYS Application in Modal Analysis of Bus Body Frame

2012 ◽  
Vol 605-607 ◽  
pp. 656-659
Author(s):  
Li Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Performance ◽  
Modal Parameters ◽  
Body Frame ◽  
Critical Problems ◽  
Bus Body ◽  
Element Method

Some critical problems of bus body frame during the modal analysis are presented by the principle of Finite Element Method. Then bus body frame is analyzed. After the modal parameters of the frame are obtained, dynamic performance of body frame is discussed to provide reference for the betterment of body frame dynamic performance design.

Modal Analysis of Bus Body Frame Based on ANSYS

2011 ◽  
Vol 396-398 ◽  
pp. 2334-2337
Author(s):  
Sheng Hui Peng ◽  
Yuan Wang ◽  
Xi Liang Dai ◽  
Jian Ping Ji
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Dynamic Performance ◽  
Modal Parameters ◽  
Body Frame ◽  
Critical Problems ◽  
Bus Body ◽  
Element Method

Some critical problems of bus body frame during the modal analysis are presented by the principle of Finite Element Method. Then bus body frame is analyzed. After the modal parameters of the frame are obtained, dynamic performance of body frame is discussed to provide reference for the betterment of body frame dynamic performance design.

scholarly journals Dynamics Characteristics of Blast Furnace Shell

2011 ◽  
Vol 2-3 ◽  
pp. 1018-1020
Author(s):  
De Chen Zhang ◽  
Yan Ping Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Blast Furnace ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Theoretical Foundation ◽  
Structural Mechanics ◽  
Mode Shapes ◽  
The Future ◽  
Element Method

Finite element method and structural mechanics method are used to study the blast furnace shell modal analysis and the natural frequencies and mode shapes have been calculated. The two methods were compared and validated , and the results provide a theoretical foundation for the anti-vibration capabilities design of blast furnace shell in the future .

Sign in / Sign up

Export Citation Format

Share Document