scholarly journals Connection looseness detection of steel grid structures using piezoceramic transducers

2018 ◽  
Vol 14 (2) ◽  
pp. 155014771875923 ◽  
Author(s):  
Shi Yan ◽  
Weiling Liu ◽  
Gangbing Song ◽  
Putian Zhao ◽  
Shuai Zhang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Evaluation Method ◽  
Guided Wave ◽  
Experimental Results ◽  
Structure Model ◽  
Nonlinear Regularity ◽  
Detection Mechanism ◽  
Element Analysis ◽  
Key Techniques

Connection looseness phenomena of steel grid structures might induce issues of lowering integrity, large deformation, even total collapse of the structures. The goal of this article is to propose an evaluation method for bolt-sphere joint looseness of steel grid structures using piezoceramic guided wave–based method through experiments and numerical simulations. A single bolt-sphere joint looseness experimental model is established and tested, considering grid member connection angles of 0°, 45°, 90°, and 180°, respectively. Then, multiple bolt-sphere joint looseness detection tests by selecting six kinds of cases for a steel grid structure model are performed. Piezoceramic patch arrays bonded on the surface of grid members are used as transducers to generate and receive detection guided waves, and external torques are applied to indirectly simulate the bolt-sphere joint looseness effect. The experimental results show that the bolt-sphere joint looseness impact on the ultrasonic wave energy attenuation has a nonlinear regularity. Based on the regularity, an evaluation method and key techniques for the bolt-sphere joint looseness detection based on guided wave energy are proposed and experimentally validated. To further clarify the bolt-sphere joint looseness detection mechanism, the ABAQUS software is used for a finite element analysis of the single bolt-sphere joint looseness evaluation. The numerical and experimental results match well, verifying the feasibility of the proposed method.

scholarly journals Fatigue crack detection in pipes with multiple mode nonlinear guided waves

2018 ◽  
Vol 18 (1) ◽  
pp. 180-192 ◽  
Author(s):  
Ruiqi Guan ◽  
Ye Lu ◽  
Kai Wang ◽  
Zhongqing Su
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Guided Waves ◽  
Second Harmonic ◽  
Experimental Testing ◽  
Harmonic Wave ◽  
Guided Wave ◽  
Element Analysis ◽  
Fatigue Crack Detection ◽  
Wave Modes

This study elaborates fundamental differences in fatigue crack detection using nonlinear guided waves between plate and pipe structures and provides an effective approach for analysing nonlinearity in pipe structures. For this purpose, guided wave propagation and interaction with microcrack in a pipe structure, which introduced a contact acoustic nonlinearity, was analysed through a finite element analysis in which the material nonlinearity was also included. To validate the simulation results, experimental testing was performed using piezoelectric transducers to generate guided waves in a specimen with a fatigue crack. Both methods revealed that the second harmonic wave generated by the breathing behaviour of the microcrack in a pipe had multiple wave modes, unlike the plate scenario using nonlinear guided waves. Therefore, a proper index which considered all the generated wave modes due to the microcrack was developed to quantify the nonlinearity, facilitating the identification of microscale damage and further assessment of the severity of the damage in pipe structures.

scholarly journals Numerical and Experimental Investigation of Guided Wave Propagation in a Multi-Wire Cable

2019 ◽  
Vol 9 (5) ◽  
pp. 1028 ◽  
Author(s):  
Pengfei Zhang ◽  
Zhifeng Tang ◽  
Fuzai Lv ◽  
Keji Yang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Wave Structure ◽  
Excitation Power ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Mechanical Coupling ◽  
Guided Wave Propagation ◽  
Contact Acoustic Nonlinearity

Ultrasonic guided waves (UGWs) have attracted attention in the nondestructive testing and structural health monitoring (SHM) of multi-wire cables. They offer such advantages as a single measurement, wide coverage of the acoustic field, and long-range propagation ability. However, the mechanical coupling of multi-wire structures complicates the propagation behaviors of guided waves and signal interpretation. In this paper, UGW propagation in these waveguides is investigated theoretically, numerically, and experimentally from the perspective of dispersion and wave structure, contact acoustic nonlinearity (CAN), and wave energy transfer. Although the performance of all possible propagating wave modes in a multi-wire cable at different frequencies could be obtained by dispersion analysis, it is ineffective to analyze the frequency behaviors of the wave signals of a certain mode, which could be analyzed using the CAN effect. The CAN phenomenon of two mechanically coupled wires in contact was observed, which was demonstrated by numerical guided wave simulation and experiments. Additionally, the measured guided wave energy of wires located in different layers of an aluminum conductor steel-reinforced cable accords with the theoretical prediction. The model of wave energy distribution in different layers of a cable also could be used to optimize the excitation power of transducers and determine the effective monitoring range of SHM.

Guided Waves as an Online Monitoring Technology for Long-Term Operation in Nuclear Power Plants: Experimental Results on a Steam Discharge Pipe

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Francesco Bertoncini ◽  
Marco Raugi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Guided Waves ◽  
Complex Structure ◽  
Theoretical Background ◽  
Guided Wave ◽  
Experimental Results ◽  
Term Operation

Guided wave (GW) testing is regularly used for finding defect locations through long-range screening using low-frequency waves (from 5 to 250 kHz). By using magnetostrictive sensors, some issues, which usually limit the application to nuclear power plants (NPPs), can be fixed. The authors have already shown the basic theoretical background and simulation results concerning a real steel pipe, used for steam discharge, with a complex structure. On the basis of such theoretical framework, a new campaign has been designed and developed on the same pipe, and the obtained experimental results are now here presented as a useful benchmark for the application of GWs as nondestructive techniques. Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPPs components.

scholarly journals Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2199 ◽  
Author(s):  
Beata Zima
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Wave Velocity ◽  
Guided Waves ◽  
Concrete Structures ◽  
Circular Cross Section ◽  
Guided Wave ◽  
Experimental Results ◽  
Reinforced Concrete Beams ◽  
Average Wave

The following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete specimens with varying extents of debonding damage by piezoelectric sensors attached at both ends of the beams. Experimental results in the form of time–domain signals registered for variable extent of debonding were compared, and the relationships relating to the damage size and time of flight and average wave velocity were proposed. The experimental results were compared with theoretical predictions based on dispersion curves traced for the free rod of circular cross-section and rectangular reinforced concrete cross-section. The high agreement of theoretical and experimental data proved that the proposed method, taking advantage of average wave velocity, can be efficiently used for assessing debonding size in reinforced concrete structures. It was shown that the development of damage size in circumferential direction has a completely different impact on wave velocity than development of debonding length. The article contains a continuation of work previously conducted on the detection of delamination in concrete structures. The proposed relationship is the next essential step for developing a diagnostics method for detecting debondings of any size and orientation.

Progress Towards a Forward Model of the Complete Acoustic Emission Process

2006 ◽  
Vol 13-14 ◽  
pp. 69-76 ◽  
Author(s):  
Paul D. Wilcox ◽  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Michael I. Friswell ◽  
M.R. Wisnom ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Guided Waves ◽  
Deterministic Model ◽  
Numerical Data ◽  
Structural Features ◽  
Guided Wave ◽  
Probability Of Detection ◽  
Modular Architecture ◽  
Element Analysis ◽  
Industrial Sectors

Acoustic emission (AE) techniques have obvious attractions for structural health monitoring (SHM) due to their extreme sensitivity and low sensor density requirement. A factor preventing the adoption of AE monitoring techniques in certain industrial sectors is the lack of a quantitative deterministic model of the AE process. In this paper, the development of a modular AE model is described that can be used to predict the received time-domain waveform at a sensor as a result of an AE event elsewhere in the structure. The model is based around guided waves since this is how AE signals propagate in many structures of interest. Separate modules within the model describe (a) the radiation pattern of guided wave modes at the source, (b) the propagation and attenuation of guided waves through the structure, (c) the interaction of guided waves with structural features and (d) the detection of guided waves with a transducer of finite spatial aperture and frequency response. The model is implemented in the frequency domain with each element formulated as a transfer function. Analytic solutions are used where possible; however, by virtue of its modular architecture it is straightforward to include numerical data obtained either experimentally or through finite element analysis (FEA) at any stage in the model. The paper will also show how the model can used, for example, to produce probability of detection (POD) data for an AE testing configuration.

scholarly journals An Investigation on a Quantitative Tomographic SHM Technique for a Containment Liner Plate in a Nuclear Power Plant with Guided Wave Mode Selection

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2819 ◽  
Author(s):  
Yonghee Lee ◽  
Younho Cho
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Elastic Wave ◽  
Nuclear Power ◽  
Guided Waves ◽  
Mode Selection ◽  
Wave Mode ◽  
Guided Wave ◽  
Element Analysis ◽  
Wave Tomography

The containment liner plate (CLP) in a nuclear power plant is the most critical part of the structure of a power plant, as it prevents the radioactive contamination of the surrounding area. This paper presents feasibility of structural health monitoring (SHM) and an elastic wave tomography method based on ultrasonic guided waves (GW), for evaluating the integrity of CLP. It aims to check the integrity for a dynamic response to a damaged isotropic structure. The proposed SHM technique relies on sensors and, therefore, it can be placed on the structure permanently and can monitor either passively or actively. For applying this method, a suitable guided wave mode tuning is required to verify wave propagation. A finite element analysis (FEA) is performed to figure out the suitable GW mode for a CLP by considering geometric and material condition. Furthermore, elastic wave tomography technique is modified to evaluate the CLP condition and its visualization. A modified reconstruction algorithm for the probabilistic inspection of damage tomography algorithm is used to quantify corrosion defects in the CLP. The location and shape of the wall-thinning defects are successfully obtained by using elastic GW based SHM. Making full use of verified GW mode to Omni-directional transducer, it can be expected to improve utilization of the SHM based evaluation technique for CLP.

An eigenfunction representation of deep waveguides with application to unconventional reservoirs

Geophysics ◽  
2021 ◽  
Vol 86 (6) ◽  
pp. T509-T521
Author(s):  
Owen Huff ◽  
Bin Luo ◽  
Ariel Lellouch ◽  
Ge Jin
Keyword(s):  
Finite Difference ◽  
Energy Distribution ◽  
Wave Energy ◽  
High Frequency ◽  
Guided Waves ◽  
Guided Wave ◽  
Low Velocity ◽  
Eagle Ford ◽  
Low Velocity Zone ◽  
Velocity Zone

Guided waves that propagate in deep low-velocity zones can be described using the displacement-stress eigenfunction theory. For a layered subsurface, these eigenfunctions provide a framework to calculate guided-wave properties at a fraction of the time required for fully numerical approaches for wave-equation modeling, such as the finite-difference approach. Using a 1D velocity model representing the low-velocity Eagle Ford Shale, an unconventional hydrocarbon reservoir, we verify the accuracy of the displacement eigenfunctions by comparing with finite-difference modeling. We use the amplitude portion of the Green’s function for source-receiver eigenfunction pairs as a proxy for expected guided-wave amplitude. These response functions are used to investigate the impact of the velocity contrast, reservoir thickness, and receiver depth on guided-wave amplitudes for discrete frequencies. We find that receivers located within the low-velocity zone record larger guided-wave amplitudes. This property may be used to infer the location of the recording array in relation to the low-velocity reservoir. We also study guided-wave energy distribution between the different layers of the Eagle Ford model and find that most of the high-frequency energy is confined to the low-velocity reservoir. We corroborate this measurement with field microseismic data recorded by distributed acoustic sensing fiber installed outside of the Eagle Ford. The data contain high-frequency body-wave energy, but the guided waves are confined to low frequencies because the recording array is outside the waveguide. We also study the energy distribution between the fundamental and first guided-wave modes as a function of the frequency and source depth and find a nodal point in the first mode for source depths originating in the middle of the low-velocity zone, which we validate with the same field data. The varying modal energy distribution can provide useful constraints for microseismic event depth estimation.

Guided Waves As an Online Monitoring Technology for Long Term Operation in NPPs: New Experimental Results on a Steam Discharge Pipe

2017 ◽  
Author(s):  
Francesco Bertoncini ◽  
Mauro Cappelli ◽  
Francesco Cordella ◽  
Marco Raugi
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Guided Waves ◽  
Complex Structure ◽  
Theoretical Background ◽  
Guided Wave ◽  
Experimental Results ◽  
Primary Circuit ◽  
Term Operation

Guided Wave (GW) testing is regularly used for finding defect locations through long range screening using low-frequency waves (from 5 to 250 kHz) [1]-[3]. Magnetostrictive sensors can overcome some issues, which usually limit the application to Nuclear Power Plants (NPPs) [4], like for example, high temperatures [5]-[6], high wall thickness of components in the primary circuit, and characteristic defect typologies. The authors have already shown the basic theoretical background, some simulations and some first experimental results concerning a real steel pipe, used for steam discharge, having a complex structure. Collecting more experimental data with a novel test campaign on the same pipe its complex structure results as a useful benchmark for the application of GWs as Non Destructive Techniques (NDT). Experimental measures using a symmetrical probe and a local probe in different configurations (pulse-echo and pitch-catch) indicate that GW testing with magnetostrictive sensors can be reliably applied to long-term monitoring of NPP components.

scholarly journals Guided Wave Energy Transfer in Composite Sandwich Structures and Application to Defect Detection

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Siavash Shoja ◽  
Viktor Berbyuk ◽  
Anders Boström
Keyword(s):  
Finite Element ◽  
Wave Energy ◽  
Guided Waves ◽  
Sandwich Structures ◽  
Guided Wave ◽  
Core Material ◽  
Energy Transmission ◽  
Composite Sandwich ◽  
Composite Sandwich Structures ◽  
Homogenization Methods

In this study, energy transmission of the guided waves propagating in composite sandwich structures is investigated in a wide range of frequencies using numerical simulations. The effects of different potential defects on the guided wave energy transmission are explored in such structures. Furthermore, the accuracy of homogenization methods for finite element modelling of guided wave propagation in sandwich structures is studied with the aim of reducing the computational burden of the simulations in the low range of frequencies. A 2D finite element model is developed and verified by comparing the results with the dispersion curves. In order to examine homogenization methods, the homogenized stiffness matrices of the sandwich material and the laminate skin are calculated using classical laminate theory. Results show that core-skin debonding causes absence of wave energy leakage from the skin to the core material in that region in a specific range of frequencies. The results are also obtained for the delamination within the skin and compared with the healthy material. Finally, for the guided waves in the low range of frequencies, it is possible to use the homogenization methods to create the finite element models and reduce the solution time.

Finite Element Analysis of Corrosion Damaged Pipeline Using PZT-Based Ultrasonic Guided Wave Energy Method

2014 ◽  
Vol 1079-1080 ◽  
pp. 368-373
Author(s):  
Shi Yan ◽  
Xin Zi Yuan ◽  
Nai Zhi Zhao ◽  
Wei Wang ◽  
Yang Cheng
Keyword(s):  
Finite Element ◽  
Wave Energy ◽  
Energy Method ◽  
Corrosion Damage ◽  
Guided Wave ◽  
Element Analysis ◽  
Finite Element Software ◽  
Ultrasonic Guided Wave ◽  
Radial Depth ◽  
Pipeline Structures

PZT-based ultrasonic guided wave has played an important role in health monitoring of pipeline structures. By using the PZT-based ultrasonic guided wave energy method and finite element software ABAQUS, the numerical simulation is performed to analyze various corrosion damaged pipeline structures, emphasizing on the damage identification, sensitivity analysis and longitudinal energy attenuation of the guided wave along various corrosion damaged pipelines. The preliminary analysis of the echo signals shows that the grass-like clutter wave belongs to echoes of the corrosion damage of the pipeline, and the wave energy spreads faster here. At the same time, by frequency spectrum analysis of the echo signal, the relationship between the reflection coefficient and the radial depth of defection is made which can be used to approximately evaluate geometrical dimension of the damage.

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