Various types of defects detection in flat and curved laminated composite plates using nonintrusive Lamb wave system

2020 ◽  
pp. 1-18
Author(s):  
Lingyu Yu ◽  
Zhaoyun Ma
Keyword(s):  
Lamb Wave ◽  
Composite Structures ◽  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Multidimensional Data ◽  
Laser Vibrometer ◽  
Wave System ◽  
Laminated Composite Plates ◽  
Data Acquisition And Processing

Abstract Composite materials are widely used in aerospace industries due to their light weight, strength, and various other desired properties. However, they are susceptible to various defects occurring during the manufacturing process or in service. Typical defects include porosity, wrinkles, and delamination. Nondestructive means of detection of the defects at any stage are of great importance to ensure quality and safety of composite structures. A nonintrusive removable Lamb wave system and accompanied methodology that is not material-dependent is presented in this paper to detect various types of typical defects in laminated composite plates, flat or curved. Through multidimensional data acquisition and processing, abnormality in waves caused by defects is captured and presented in inspection images. The methodologies are demonstrated in 2 cases: delamination in a curved plate, and wrinkles in a flat plate. Overall the results show that Lamb waves using the piezoelectric transducer and laser vibrometer system can be used for various types of defects inspection in flat or curved composite plates.

Lamb-Wave-Based Damage Identification in Laminated Composite Plates

2014 ◽  
Vol 1014 ◽  
pp. 3-8
Author(s):  
Zai Lin Yang ◽  
Hamada M. Elgamal ◽  
Jian Wei Zhang
Keyword(s):  
Lamb Wave ◽  
Structural Damage ◽  
Damage Identification ◽  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
High Sensitivity ◽  
Scattered Wave ◽  
Propagation Path ◽  
Laminated Composite Plates

With advantages including capability of propagation over a significant distance and high sensitivity to abnormalities and inhomogeneity near the wave propagation path, Lamb waves can be energised to disseminate in a structure and any changes in material properties or structural geometry created by a discontinuity, boundary or structural damage can be identified by examining the scattered wave signals. This paper presents an overview of the Lamb-wave-based damage identification in laminated composite plates including the formulation of lamb waves in an isotropic plate.

Determination of Vibration Source Locations in Laminated Composite Plates Using Lamb Wave Analysis

2010 ◽  
Vol 123-125 ◽  
pp. 899-902
Author(s):  
Chao Du ◽  
Qing Qing Ni ◽  
Toshiaki Natsuki
Keyword(s):  
Lamb Wave ◽  
Guided Waves ◽  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Wave Dispersion ◽  
Laminated Plates ◽  
Vibration Source ◽  
Arrival Times ◽  
Wave Velocities

Signals propagate on plate-like structures as ultrasonic guided waves, and analysis of Lamb waves has been widely used for on-line monitoring. In this study, the wave velocities of symmetric and anti-symmetric modes in various directions of propagation were investigated. Since the wave velocities of these two modes are different, it is possible to compute the difference in their arrival times when these waves propagated the distance from the vibration source to sensor. This paper presents an evaluation formulation of wave velocity and describes a generalized algorithm for locating a vibration source on a thin, laminated plate. With the different velocities of two modes based on Lamb wave dispersion, the method uses two sensors to locate the source on a semi-infinite interval of a plate. The experimental procedure supporting this method employs pencil lead breaks to simulate vibration sources on quasi-isotropic and unidirectional laminated plates. The transient signals generated in this way are transformed using a wavelet transform. The vibration source locations are then detected by utilizing the distinct wave velocities and arrival times of the symmetric and anti-symmetric wave modes. The method is an effective technique for identifying impact locations on plate-like structures.

Optimization for the Maximum Buckling Loads of Laminated Composite Plates – Comparison of Various Design Methods

2007 ◽  
Vol 334-335 ◽  
pp. 89-92 ◽  
Author(s):  
Shinya Honda ◽  
Yoshihiro Narita ◽  
Katsuhiko Sasaki
Keyword(s):  
Composite Structures ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Advantages And Disadvantages ◽  
Optimum Parameters ◽  
Plate Elements ◽  
Buckling Optimization ◽  
Fiber Orientation Angle

Structural plate elements in composite structures are typically fabricated by stacking orthotropic layers, each of which is composed of reinforcing fibers and matrix materials. In this work, three optimum design approaches are compared to clarify the advantages and disadvantages for optimizing the buckling performance of laminated composite plates. The first approach is developed recently by the authors, where the buckling load is maximized with respect to the lamination parameters by a gradient method and then the optimum lay-up design is determined by minimizing the errors between the optimum parameters and parameters for all possible discrete lay-ups. The second approach is the layerwise optimization (LO) approach where the fiber orientation angle in each layer is optimized step-by-step by repeating one dimensional search. The third one is a direct application of a simple genetic algorithm (SGA). In numerical examples, three sets of results are compared to discuss on the methodology for buckling optimization.

Lamb waves in laminated composite plates

1984 ◽  
Vol 76 (S1) ◽  
pp. S66-S66
Author(s):  
D. E. Chimenti ◽  
Adnan H. Nayfeh
Keyword(s):  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates

Electroelastic modeling of thin-laminated composite plates with surface-bonded piezo-patches using Rayleigh–Ritz method

2018 ◽  
Vol 29 (10) ◽  
pp. 2192-2205 ◽  
Author(s):  
Mehmet Murat Gozum ◽  
Amirreza Aghakhani ◽  
Gokhan Serhat ◽  
Ipek Basdogan
Keyword(s):  
Modal Analysis ◽  
Vibration Analysis ◽  
Composite Structures ◽  
Ritz Method ◽  
Laminated Composite ◽  
Composite Plates ◽  
System Level ◽  
Laminated Composite Plates ◽  
Modeling Tools ◽  
Analysis And Design

Laminated composite panels are extensively used in various engineering applications. Piezoelectric transducers can be integrated into such composite structures for a variety of vibration control and energy harvesting applications. Analyzing the structural dynamics of such electromechanical systems requires precise modeling tools which properly consider the coupling between the piezoelectric elements and the laminates. Although previous analytical models in the literature cover vibration analysis of laminated composite plates with fully covered piezoelectric layers, they do not provide a formulation for modeling the piezoelectric patches that partially cover the plate surface. In this study, a methodology for vibration analysis of laminated composite plates with surface-bonded piezo-patches is developed. Rayleigh–Ritz method is used for solving the modal analysis and obtaining the frequency response functions. The developed model includes mass and stiffness contribution of the piezo-patches as well as the two-way electromechanical coupling effect. Moreover, an accelerated method is developed for reducing the computation time of the modal analysis solution. For validations, system-level finite element simulations are performed in ANSYS software. The results show that the developed analytical model can be utilized for accurate and efficient analysis and design of laminated composite plates with surface-bonded piezo-patches.

scholarly journals An Experimental Investigation on Damage Loads of Butterfly Joints in Composite Structures

2007 ◽  
Vol 16 (6) ◽  
pp. 096369350701600 ◽  
Author(s):  
Muzaffer Topçu ◽  
Gürkan Altan ◽  
Emin Ergun
Keyword(s):  
Glass Fibre ◽  
Composite Structure ◽  
Composite Structures ◽  
Epoxy Composite ◽  
Laminated Composite ◽  
Composite Plates ◽  
Hot Press ◽  
Laminated Composite Plates ◽  
Joint Geometry ◽  
Lock In

This study is performed experimentally to investigate damage forces formed on glass-fibre laminated composite plates that are jointed with a component in the shape of butterfly. Pressing it into the mould in a hot press machine produced a glass fibre-epoxy composite plate. Specimens and locking parts in the shape of butterfly were cut using water jet. Experiments were performed in different values of the ratio of the end width of butterfly to the width of the specimen ( w/ b), the ratio of the middle width of butterfly to the end width of butterfly ( x/ w) and the ratio of the half-length of butterfly to the width of the specimen ( y/ b). Using these values, the effects of joint geometry parameters were evaluated. To be able to see the effect of material variations as well, the joint lock in the shape of butterfly was made up of both metal and composite materials. Although the loading capacity of the composite butterfly is lower than that of the metal butterfly, it carries loads for much longer times. Before a composite structure develops damage, damage occurred in the composite butterfly can be seen and, with the repair of the butterfly lock, the life of the composite structure can be extended.

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