Interval analysis of mode shapes to identify damage in beam structures

2021 ◽  
Vol 52 (10) ◽  
pp. 1064-1072
Author(s):  
M. Abdulkareem ◽  
A. Ganiyu ◽  
O. Nathaniel ◽  
I. Mallum ◽  
W. Dunu
Keyword(s):  
Interval Analysis ◽  
Mode Shapes ◽  
Beam Structures

FEM Free Damage Detection of Beam Structures Using the Deflections Estimated by Modal Flexibility Matrix

2021 ◽  
pp. 2150128
Author(s):  
Wen-Yu He ◽  
Wei-Xin Ren ◽  
Lei Cao ◽  
Quan Wang
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Damage Index ◽  
Element Model ◽  
Mode Shapes ◽  
Beam Structures ◽  
Flexibility Matrix ◽  
Damage Quantification ◽  
Modal Flexibility ◽  
The Cost

The deflection of the beam estimated from modal flexibility matrix (MFM) indirectly is used in structural damage detection due to the fact that deflection is less sensitive to experimental noise than the element in MFM. However, the requirement for mass-normalized mode shapes (MMSs) with a high spatial resolution and the difficulty in damage quantification restricts the practicability of MFM-based deflection damage detection. A damage detection method using the deflections estimated from MFM is proposed for beam structures. The MMSs of beams are identified by using a parked vehicle. The MFM is then formulated to estimate the positive-bending-inspection-load (PBIL) caused deflection. The change of deflection curvature (CDC) is defined as a damage index to localize damage. The relationship between the damage severity and the deflection curvatures is further investigated and a damage quantification approach is proposed accordingly. Numerical and experimental examples indicated that the presented approach can detect damages with adequate accuracy at the cost of limited number of sensors. No finite element model (FEM) is required during the whole detection process.

scholarly journals Looseness localization for bolted joints using Bayesian operational modal analysis and modal strain energy

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401880869 ◽  
Author(s):  
Yu-Jia Hu ◽  
Wei-Gong Guo ◽  
Cheng Jiang ◽  
Yun-Lai Zhou ◽  
Weidong Zhu
Keyword(s):  
Modal Analysis ◽  
Strain Energy ◽  
Damage Index ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Bolted Joints ◽  
Mode Shapes ◽  
Bolted Connections ◽  
Modal Strain Energy ◽  
Beam Structures

Bayesian operational modal analysis and modal strain energy are employed for determining the damage and looseness of bolted joints in beam structures under ambient excitation. With this ambient modal identification technique, mode shapes of a damaged beam structure with loosened bolted connections are obtained based on Bayesian theory. Then, the corresponding modal strain energy can be calculated based on the mode shapes. The modal strain energy of the structure with loosened bolted connections is compared with the theoretical one without bolted joints to define a damage index. This approach uses vibration-based nondestructive testing of locations and looseness of bolted joints in beam structures with different boundary conditions by first obtaining modal parameters from ambient vibration data. The damage index is then used to identify locations and looseness of bolted joints in beam structures with single or multiple bolted joints. Furthermore, the comparison between damage indexes due to different looseness levels of bolted connections demonstrates a qualitatively proportional relationship.

Study on dynamics responses and applications of non-uniform beam structure under crosswind

2021 ◽  
pp. 107754632110183
Author(s):  
Peng Wang ◽  
Nan Wu ◽  
Haitao Luo ◽  
Zhili Sun
Keyword(s):  
Adomian Decomposition Method ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Beam Structure ◽  
Beam Structures ◽  
Adomian Decomposition ◽  
Positive Exponent ◽  
The One ◽  
Negative Exponential ◽  
Nonuniform Beam

This article studies the dynamic responses of the nonuniform beam structure under the action of the crosswind and its applications on vibration control and utilization (energy harvesting based on the piezoelectric beam). First, the natural frequencies and mode shapes of the nonuniform beam are solved by Adomian decomposition method and then the beam vibration deflections and piezoelectric charges are derived. Furthermore, from the theoretical model and solutions, the influences of different taper ratios and outer diameters on the deflections of nonuniform beam structures with the same mass are studied. The deflections of nonuniform same mass beam structures with positive and negative exponential profiles are also compared. It is demonstrated that the deflections of the beam decrease with the increase of taper ratios and increase with the increase of outer diameters. Under the wind velocity ranges of 10 m/s to 26 m/s, the deflection of the nonuniform beam with a negative exponent profile is less than the one with a positive exponent profile. Through this study, the optimal nonuniform beam structure with either small deflection or high piezoelectric charge output can be designed according to different wind velocities and demands.

Network-Conscious Damage Tracing Method for Beam Structures Based on Measurements Acquired by Distributed MEMS Gyroscopes

Aerospace ◽  
2004 ◽  
Author(s):  
Arata Masuda ◽  
Akira Sone
Keyword(s):  
Damage Index ◽  
Mode Shapes ◽  
Beam Structures ◽  
Vibratory Gyroscopes ◽  
Damage Indices ◽  
Mode Separation ◽  
Modal Flexibility ◽  
Mems Gyroscopes ◽  
Evaluation Algorithm ◽  
Tracing Method

The aim of this conceptual paper is to develop a damage tracing method to detect and track the evolution of structural damages in aerospace structures, in particular, large beam structures, considering the applicability in a decentralized computing environment of wireless sensor networks. We first present a modal flexibility-based damage indices that have simple and intuitive physical interpretation. Since the damage indices are computed using angular mode shapes of the lowest several modes, vibratory gyroscopes are adopted as the sensing device in this approach. The damage evaluation algorithm is then modified to a decentralized form, which is to be implemented as the local computation of mode separation at each sensor unit and the global computation of the damage index at the central monitoring station. Some illustrative experiments simulating both stationary damages and sudden damages are conducted to show that the proposed method is capable to indicate the location of the damages and the time when they occur.

Prediction of Changes in Modal Properties of the Euler–Bernoulli Beam Structures Due to the Modification of Its Spatial Properties

2017 ◽  
Vol 17 (05) ◽  
pp. 1740014 ◽  
Author(s):  
Milan Naď ◽  
Ladislav Rolník ◽  
Lenka Čičmancová
Keyword(s):  
Dynamical Behavior ◽  
Mode Shapes ◽  
Structural Elements ◽  
Bernoulli Beam ◽  
Beam Structure ◽  
Beam Structures ◽  
Spatial Properties ◽  
Modal Properties ◽  
Euler Bernoulli Beam ◽  
Operating Regimes

The beams can be considered as fundamental structural elements applied in many technical structures and equipment. In the operating regimes, these beam structures are very often loaded by the time-dependent forces which cause their undesirable dynamical behavior and the whole system is getting into critical resonant state. It is clear that the reduction of the level of unwanted vibrations or prevention of their occurrence should be one of the important objectives in the design of machine equipment and structures. To achieve these aims, the knowledge of modal properties of beam structures in relation to their internal structure is necessary. The insertion of reinforcing core into a beam body is one of the possible techniques to achieve the required changes in modal properties (mode shapes, natural frequencies) of the beam structure. The dependency of the modal properties of structurally modified beam structure on the geometric parameters and material properties of the inserted reinforcing core is studied in this paper.

Vibration Analysis of Reinforced Beam Structure Using Partially Inserted Longitudinal Core

2014 ◽  
Vol 693 ◽  
pp. 311-316 ◽  
Author(s):  
Milan Nad ◽  
Ladislav Rolník ◽  
Jozef Steinhauser
Keyword(s):  
Dynamic Properties ◽  
Machining Process ◽  
Mode Shapes ◽  
Technical Equipment ◽  
Beam Structure ◽  
Machined Surface ◽  
Beam Structures ◽  
Modal Properties ◽  
Wear Tool ◽  
Lathe Tool

The beam structures are considered as one of the most fundamental building elements of technical equipment. Many of the machining tools (for example lathe tool) may be also regarded as the beam structures. The various excitation effects are affecting the machining tools during the machining process. Cutting speeds, cutting forces, chip-making manner, the stiffness of MTW (machine-tool-workpiece) system are predominant effects affecting the dynamics of MTW system and also influencing the machining process (roughness of the machined surface, tool wear, tool or workpiece damage, noise generated by the machining process, etc.). Depending on the excitation effects, the machining tool body (beam structure) must have the required dynamic properties. The modification of beam modal properties based on embedding of inner reinforcing core is presented in this paper. The main aim of the modification is to change the modal properties (mode shapes, natural frequencies) of the beam body.

Dynamic Detection of Damage in Structure

1991 ◽  
Author(s):  
Qinghua Mao ◽  
Xiaofeng Shen
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Theoretical Method ◽  
Mode Shapes ◽  
Beam Structures ◽  
Dynamic Detection

Abstract When a damage exists in a structure, the dynamic characteristics of the structure are changed. A great deal of effort has been elaborated to determine the position and the amount of the damage by using the natural frequencies and the mode shapes. In this paper, a theoretical method is given to detect the damage in a structure based on the changes of its natural frequencies and the mode shapes. After determining the location of the damage, a correcting factor describing a reduction in stiffness of damaged element gives the amount of the damage. This method is proved on two examples of beam structures.

Eigensolution of piezoelectric energy harvesters with geometric discontinuities: Analytical modeling and validation

2012 ◽  
Vol 24 (6) ◽  
pp. 729-744 ◽  
Author(s):  
Adam M Wickenheiser
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Mode Shapes ◽  
Transfer Matrices ◽  
Coupling Effects ◽  
Beam Structures ◽  
Energy Harvesters ◽  
Piezoelectric Energy

Although cantilevered beams are the most prolific design for resonant piezoelectric energy harvesters, other topologies have been studied for their compactness or conformability to their host structures’ geometry. These more complex structures have been analyzed using custom analytical models developed from the first principles or finite-element methods to compute their eigensolutions and piezoelectric coupling effects. This article discusses the use of the transfer matrix method to derive analytical solutions to beam structures with pointwise discontinuities, bends, or lumped inertias between members or at the tip. Euler–Bernoulli beam theory is used to derive transfer matrices for the uniform beam segments, and point transfer matrices are derived to handle discontinuities in the structure between beam segments. The eigensolution of the transfer matrix is shown to produce the natural frequencies and mode shapes for these structures. Subsequently, the electromechanical coupling effects are incorporated, and the base excitation problem is considered. Parametric case studies are provided for beam structures with varying piezoelectric layer coverage and angle between members. Finally, these results are compared to finite-element solutions using COMSOL, and the modeling discrepancies are discussed. Based on the favorable comparison between these two methods, the utility and accuracy of the transfer matrix method are proven.

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