scholarly journals Direct Calculation of the Group Velocity for Two-Dimensional Complex, Composite and Periodic Structures Using a Wave and Finite Element Scheme

2021 ◽  
Vol 11 (10) ◽  
pp. 4319
Author(s):  
Muhammad Khalid Malik ◽  
Dimitrios Chronopoulos ◽  
Francesco Ciampa
Keyword(s):  
Finite Element ◽  
Structural Health Monitoring ◽  
Group Velocity ◽  
Health Monitoring ◽  
Periodic Structures ◽  
Velocity Profiles ◽  
Guided Wave ◽  
Finite Element Scheme ◽  
Element Scheme ◽  
Structural Health

Guided waves have immense potential for structural health monitoring applications in numerous industries including aerospace. It is necessary to evaluate guided wave dispersion characteristics, i.e., group velocity and phase velocity profiles, for using them effectively. For complex structures, the profiles can have highly irregular shapes. In this work, a direct method for calculating the group velocity profiles for complex, composite, and periodic structures using a wave and finite element scheme is presented. The group velocity calculation technique is easy to implement, highly computationally efficient, and works with the standard finite element formulation. The major contribution is summarised in the form of a comprehensive algorithm for calculating the group velocity profiles. The method is compared with the existing analytical and numerical methods for calculation of dispersion curves. Finally, an experimental study in a multilayered composite plate is conducted and the results are found to be in good agreement. The technique is suitable to be used in all guided wave application areas such as material characterisation, non-destructive testing, and structural health monitoring.

Modeling Ultrasonic Guided Wave Generation From Piezoelectric Fiber Composite Strip Actuators

2010 ◽  
Author(s):  
Sheng Li ◽  
Cliff J. Lissenden
Keyword(s):  
Finite Element ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Fiber Composite ◽  
Wave Generation ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Micromechanical Modeling ◽  
Structural Health ◽  
Ultrasonic Guided Wave

Structural health monitoring (SHM) and condition based maintenance (CBM) are keys to shifting the paradigm from schedule based maintenance to cost effective operation and maintenance of reliable systems. Continuous comb transducer strips have the potential to generate ultrasonic guided waves for structural health monitoring of plate and shell structures (pipelines, pressure vessels, storage tanks, airframes). A theoretically driven approach, based on the application of wave mechanics principles, is used to research and design a network of strip sensor. Fibrous piezoelectric composites are considered for the comb elements, widely expanding the design space of these elements to include fiber orientation and volume fraction in addition to size, configuration, and location of the electrodes. Piezoelectric and mechanical properties for these innovative sensor designs are estimated through micromechanical modeling. Specifically, micromechanics enables us to consider different fiber orientations and constituent properties and provides the composite properties for input to finite element analysis of wave propagation. Finite element simulations of ultrasonic guided wave generation and propagation using Abaqus Explicit-Standard Co-Simulation are conducted in order to design the sensory system.

Structural health monitoring using torsional guided wave electromagnetic acoustic transducers

2016 ◽  
Vol 17 (1) ◽  
pp. 24-38 ◽  
Author(s):  
Balint Herdovics ◽  
Frederic Cegla
Keyword(s):  
Finite Element ◽  
Structural Health Monitoring ◽  
Lorentz Force ◽  
Eddy Current ◽  
Health Monitoring ◽  
Guided Wave ◽  
Electromagnetic Acoustic Transducer ◽  
Artificial Defect ◽  
Structural Health ◽  
Acoustic Transducer

Torsional guided wave inspection is widely used for pipeline inspection. Piezoelectric and magnetostrictive transducers are most commonly used to generate torsional guided waves. These types of transducers require bonding or mechanical contact to the pipe which can result in changes over time which are undesirable for structural health monitoring. This article presents a non-contact Lorentz force–based electromagnetic acoustic transducer for torsional guided wave monitoring of pipelines. First, the excitation mechanism of the transducer is simulated by analyzing the eddy current and the static magnetic field using the finite element method. An electromagnetic acoustic transducer transformer model is presented which describes the eddy current generation transfer function and the ultrasound excitation. Independently simulated eddy current and magnetic fields are used to calculate the Lorentz force that an electromagnetic acoustic transducer array induces on the surface of a 3-in schedule 40 pipe, and an explicit finite element solver is then used to simulate the elastic wave propagation in the pipe. Then, the reception mechanism and the expected received signal levels are discussed. The construction of an experimental transducer is described, and measurement results from the transducer setup are presented. The measured and modeled performance agree well. Finally, a monitoring example is presented where an artificial defect with 3% reflection coefficient is introduced and successfully detected with the designed sensor.

scholarly journals Research on the Progress of Interdigital Transducer (IDT) for Structural Damage Monitoring

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wang Ziping ◽  
Xiong Xiqiang ◽  
Qian Lei ◽  
Wang Jiatao ◽  
Fei Yue ◽  
...  
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Damage ◽  
Large Scale ◽  
Safety Information ◽  
Health And Safety ◽  
Guided Wave ◽  
Structural Safety ◽  
Structural Health ◽  
Damage Monitoring

In the application of Structural Health Monitoring (SHM) methods and related technologies, the transducer used for electroacoustic conversion has gradually become a key component of SHM systems because of its unique function of transmitting structural safety information. By comparing and analyzing the health and safety of large-scale structures, the related theories and methods of Structural Health Monitoring (SHM) based on ultrasonic guided waves are studied. The key technologies and research status of the interdigital guided wave transducer arrays which used for structural damage detection are introduced. The application fields of interdigital transducers are summarized. The key technical and scientific problems solved by IDT for Structural Damage Monitoring (SHM) are presented. Finally, the development of IDT technology and this research project are summarised.

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