scholarly journals Assessment of the Structural Integrity of Timber Utility Poles Using Ultrasonic Waves

2021 ◽  
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Structural Integrity ◽  
Numerical Data ◽  
Ultrasonic Waves ◽  
Propagation Characteristics ◽  
Utility Pole ◽  
Utility Poles ◽  
Non Destructive ◽  
Wave Modes

Abstract. In this study, guided stress waves were used to evaluate the conditions of a timber utility pole experimentally and numerically using COMSOL Multiphysics. Macro Fiber Composites (MFCs), due to their flexibility and convenience to install on curved surfaces, were used to actuate and sense guided waves along the tested specimens. Based on the wave propagation characteristics in these types of structures, an MFC actuator ring, which was developed in the previous work, was applied to tune and enhance the propagating wave modes of interest. The designed ring was used to excite longitudinal ultrasonic wave modes, mainly L(0,1), for the purpose of determining the embedded length of the pole. For the damage localization a single MFC excitation was used which proved to be more efficient than the actuator ring. Embedding the timber in soil had minimum impact on the wave propagation characteristics, given that the waves were confined in the timber pole with minimal leakage to the surrounding. The embedded length was determined accurately for sound and damage timber, using both experimental and numerical data with an error of less than 3 %. The deterioration in the timber structure, within the embedded region, was also evaluated with high accuracy of 93 %. Based on the obtained results, guided waves have high potential to be used as a non-destructive tool for the assessment and evaluation of timber utility poles.

Influence of the applied pressure of the transducer on the propagation speed of the ultrasonic wave in wood

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edgar V.M. Carrasco ◽  
Rejane C. Alves ◽  
Mônica A. Smits ◽  
Vinnicius D. Pizzol ◽  
Ana Lucia C. Oliveira ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Applied Pressure ◽  
Pressure Gauge ◽  
Eucalyptus Grandis ◽  
Propagation Speed ◽  
Ultrasonic Waves ◽  
Ultrasonic Speed ◽  
Wave Propagation Speed ◽  
Propagation Technique ◽  
Non Destructive

Abstract The non-destructive wave propagation technique is used to estimate the wood’s modulus of elasticity. The propagation speed of ultrasonic waves is influenced by some factors, among them: the type of transducer used in the test, the form of coupling and the sensitivity of the transducers. The objective of the study was to evaluate the influence of the contact pressure of the transducers on the ultrasonic speed. Ninety-eight tests were carried out on specimens of the species Eucalyptus grandis, with dimensions of 120 × 120 × 50 mm. The calibration of the pressure exerted by the transducer was controlled by a pressure gauge using a previously calibrated load cell. The robust statistical analysis allowed to validate the experimental results and to obtain consistent conclusions. The results showed that the wave propagation speed is not influenced by the pressure exerted by the transducer.

scholarly journals High Frequency Ultrasonic Wave Propagation in  Anisotropic Materials

2021 ◽  
Author(s):  
◽  
Andrew Paul Dawson
Keyword(s):  
Wave Propagation ◽  
Ultrasonic Wave ◽  
High Frequency ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Tissue Characterisation ◽  
Ultrasonic Wave Propagation ◽  
Matching Layer ◽  
Fibrous Tissues ◽  
Wave Modes

<p>The influence of highly regular, anisotropic, microstructured materials on high frequency ultrasonic wave propagation was investigated in this work. Microstructure, often only treated as a source of scattering, significantly influences high frequency ultrasonic waves, resulting in unexpected guided wave modes. Tissues, such as skin or muscle, are treated as homogeneous by current medical ultrasound systems, but actually consist of highly anisotropic micron-sized fibres. As these systems increase towards 100 MHz, these fibres will significantly influence propagating waves leading to guided wave modes. The effect of these modes on image quality must be considered. However, before studies can be undertaken on fibrous tissues, wave propagation in more ideal structures must be first understood. After the construction of a suitable high frequency ultrasound experimental system, finite element modelling and experimental characterisation of high frequency (20-200 MHz) ultrasonic waves in ideal, collinear, nanostructured alumina was carried out. These results revealed interesting waveguiding phenomena, and also identified the potential and significant advantages of using a microstructured material as an alternative acoustic matching layer in ultrasonic transducer design. Tailorable acoustic impedances were achieved from 4-17 MRayl, covering the impedance range of 7-12 MRayl most commonly required by transducer matching layers. Attenuation coefficients as low as 3.5 dBmm-1 were measured at 100 MHz, which is excellent when compared with 500 dBmm-1 that was measured for a state of the art loaded epoxy matching layer at the same frequency. Reception of ultrasound without the restriction of critical angles was also achieved, and no dispersion was observed in these structures (unlike current matching layers) until at least 200 MHz. In addition, to make a significant step forward towards high frequency tissue characterisation, novel microstructured poly(vinyl alcohol) tissue-mimicking phantoms were also developed. These phantoms possessed acoustic and microstructural properties representative of fibrous tissues, much more realistic than currently used homogeneous phantoms. The attenuation coefficient measured along the direction of PVA alignment in an example phantom was 8 dBmm-1 at 30 MHz, in excellent agreement with healthy human myocardium. This method will allow the fabrication of more realistic and repeatable phantoms for future high frequency tissue characterisation studies.</p>

scholarly journals Automated Health Condition Diagnosis of in situ Wood Utility Poles Using an Intelligent Non-Destructive Evaluation (NDE) Framework

2020 ◽  
Vol 20 (10) ◽  
pp. 2042002 ◽  
Author(s):  
Yang Yu ◽  
Mahbube Subhani ◽  
Azadeh Noori Hoshyar ◽  
Jianchun Li ◽  
Huan Li
Keyword(s):  
Communication Networks ◽  
Guided Waves ◽  
Power Transmission ◽  
Influence Factors ◽  
Principal Component ◽  
Field Testing ◽  
Health Condition ◽  
Non Destructive Evaluation ◽  
Utility Poles ◽  
Non Destructive

Wood utility poles are widely applied in power transmission and telecommunication systems in Australia. Because of a variety of external influence factors, such as fungi, termite and environmental conditions, failure of poles due to the wood degradation with time is of common occurrence with high degree uncertainty. The pole failure may result in serious consequences including both economic and public safety. Therefore, accurately and timely identifying the health condition of the utility poles is of great significance for economic and safe operation of electricity and communication networks. In this paper, a novel non-destructive evaluation (NDE) framework with advanced signal processing and artificial intelligence (AI) techniques is developed to diagnose the condition of utility pole in field. To begin with, the guided waves (GWs) generated within the pole is measured using multi-sensing technique, avoiding difficult interpretation of various wave modes which cannot be detected by only one sensor. Then, empirical mode decomposition (EMD) and principal component analysis (PCA) are employed to extract and select damage-sensitive features from the captured GW signals. Additionally, the up-to-date machine learning (ML) techniques are adopted to diagnose the health condition of the pole based on selected signal patterns. Eventually, the performance of the developed NDE framework is evaluated using the field testing data from 15 new and 24 decommissioned utility poles at the pole yard in Sydney.

Ultrasonic Guided Wave Testing of Finned Tubing

2015 ◽  
Author(s):  
Owen M. Malinowski ◽  
Matthew S. Lindsey ◽  
Jason K. Van Velsor
Keyword(s):  
Wave Propagation ◽  
Guided Waves ◽  
Tube Wall ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Complex Nature ◽  
Inspection Method ◽  
Ultrasonic Guided Wave ◽  
Guided Wave Propagation ◽  
Wave Modes

In the past few decades, ultrasonic guided waves have been utilized more frequently Non-Destructive Testing (NDT); most notably, in the qualitative screening of buried piping. However, only a fraction of their potential applications in NDT have been fully realized. This is due, in part, to their complex nature, as well as the high level of expertise required to understand and utilize their propagation characteristics. The mode/frequency combinations that can be generated in a particular structure depend on geometry and material properties and are represented by the so-called dispersion curves. Although extensive research has been done in ultrasonic guided wave propagation in various geometries and materials, the treatment of ultrasonic guided wave propagation in periodic structures has received little attention. In this paper, academic aspects of ultrasonic guided wave propagation in structures with periodicity in the wave vector direction are investigated, with the practical purpose of developing an ultrasonic guided wave based inspection technique for finned tubing. Theoretical, numerical, and experimental methods are employed. The results of this investigation show excellent agreement between theory, numerical modeling, and experimentation; all of which indicate that ultrasonic guided waves will propagate coherently in finned tube only if the proper wave modes and frequencies are selected. It is shown that the frequencies at which propagating wave modes exist can be predicted theoretically and numerically, and depend strongly on the fin geometry. Furthermore, the results show that these propagating wave modes are capable of screening for and identifying the axial location of damage in the tube wall, as well as separation of the fins from the tube wall. The conclusion drawn from these results is that Guided Wave Testing (GWT) is a viable inspection method for screening finned tubing.

scholarly journals Ultrasonic Methods

2021 ◽  
pp. 87-131
Author(s):  
Vykintas Samaitis ◽  
Elena Jasiūnienė ◽  
Pawel Packo ◽  
Damira Smagulova
Keyword(s):  
Long Range ◽  
Guided Waves ◽  
Structural Integrity ◽  
Ultrasonic Inspection ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Bulk Wave ◽  
Destructive Testing ◽  
Fibre Breakage ◽  
Ultrasonic Methods

AbstractUltrasonic inspection is a well recognized technique for non-destructive testing of aircraft components. It provides both local highly sensitive inspection in the vicinity of the sensor and long-range structural assessment by means of guided waves. In general, the properties of ultrasonic waves like velocity, attenuation and propagation characteristics such as reflection, transmission and scattering depend on composition and structural integrity of the material. Hence, ultrasonic inspection is commonly used as a primary tool for active inspection of aircraft components such as engine covers, wing skins and fuselages with the aim to detect, localise and describe delaminations, voids, fibre breakage and ply waviness. This chapter mainly focuses on long range guided wave structural health monitoring, as aircraft components require rapid evaluation of large components preferably in real time without the necessity for grouding of an aircraft. In few upcoming chapters advantages and shortcommings of bulk wave and guided wave ultrasonic inspection is presented, fundamentals of guided wave propagation and damage detection are reviewed, the reliability of guided wave SHM is discussed and some recent examples of guided wave applications to SHM of aerospace components are given.

Monitoring and Imaging of Bolted Steel Plate Joints Using Ultrasonic Guided Waves

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Jay Kumar Shah ◽  
Abhijit Mukherjee
Keyword(s):  
Piezoelectric Ceramic ◽  
Guided Waves ◽  
Steel Plate ◽  
Steel Structures ◽  
Ultrasonic Waves ◽  
Bolted Joints ◽  
Ultrasonic Guided Waves ◽  
Automated Method ◽  
Non Destructive ◽  
Joint Integrity

Abstract Steel structures with bolted joints are easily dismantled and repurposed. However, maintaining joint integrity is a challenge. This paper reports a non-destructive methodology to monitor steel bolted joints. Piezoelectric ceramic patches have been surface bonded in the joint for transmission and reception of guided ultrasonic waves. Both single and multiple bolted joints have been investigated. It has been demonstrated that the variation in acoustic impedance due at the bolt interface can be discerned and calibrated with bolt torque level. The recorded reflections from interfaces are used as inputs for a newly developed imaging algorithm. The proposed method has the potential to be a reference-free and fully automated method.

Study on Ultrasonic Guided Waves in Fluid-Filled Pipes Surrounded by Water

2006 ◽  
Author(s):  
Shijiu Jin ◽  
Liying Sun ◽  
Guichun Liu ◽  
Yibo Li ◽  
Hong Zhang
Keyword(s):  
Guided Waves ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Ultrasonic Guided Waves ◽  
Fluid Loading ◽  
Inspection Method ◽  
Ultrasonic Guided Wave ◽  
Oil Company ◽  
Non Destructive ◽  
Good Agreement

A new non-destructive pipe inspection method, ultrasonic guided wave method as well as the comparison between ultrasonics and guided waves is introduced. An investigation of the guided ultrasonic waves traveling along pipes with fluid loading on the inside and outside of the pipe is described. The effect of inner and outer media has been researched by considering a steel pipe with air and water inside and outside the experimental pipe. Site experiment was carried out on a heating pipe in the resident area of Bohai Oil Company, China. A typical cylindrical guided wave, longitudinal guided wave was used to examine pipes with artificial defects and its propagation characteristics along the pipe were studied. Good agreement has been obtained between the experiments and predictions for pipes with different loading on the pipe.

scholarly journals High-Frequency Guided Waves for Corrosion Thickness Loss Monitoring

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Daniel Chew ◽  
Bernard Masserey ◽  
Paul Fromme
Keyword(s):  
Wave Propagation ◽  
Wall Thickness ◽  
Lamb Wave ◽  
High Frequency ◽  
Guided Waves ◽  
Plate Thickness ◽  
Corrosion Damage ◽  
Element Model ◽  
Guided Wave ◽  
Wave Modes

Abstract Adverse environmental conditions result in corrosion during the life cycle of marine structures such as pipelines, offshore oil platforms, and ships. Generalized corrosion leading to the loss of wall thickness can cause the degradation of the integrity, strength, and load bearing capacity of the structure. Nondestructive detection and monitoring of corrosion damage in difficult to access areas can be achieved using high-frequency guided waves propagating along the structure. Using standard ultrasonic wedge transducers with single-sided access to the structure, specific high-frequency guided wave modes (overlap of both fundamental Lamb wave modes) were generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the guided wave modes depend on the thickness of the structure and were measured using a noncontact laser interferometer. Numerical simulations using a two-dimensional finite element model were performed to visualize and predict the guided wave propagation and energy transfer across the plate thickness. During laboratory experiments, the wall thickness was reduced uniformly by milling of one steel plate specimen. In a second step, wall thickness reduction was induced using accelerated corrosion for two mild steel plates. The corrosion damage was monitored based on the effect on the wave propagation and interference (beating effect) of the Lamb wave modes in the frequency domain. Good agreement of the measured beatlengths with theoretical predictions was achieved, and the sensitivity of the methodology was ascertained, showing that high-frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations.

scholarly journals Theoretical model of guided waves in a bone-mimicking plate coupled with soft-tissue layers

2021 ◽  
Author(s):  
Hoai Nguyen ◽  
Ductho Le ◽  
Emmanuel Plan ◽  
Son Tung Dang ◽  
Haidang Phan
Keyword(s):  
Theoretical Model ◽  
Soft Tissue ◽  
Quantitative Ultrasound ◽  
Guided Waves ◽  
Soft Tissues ◽  
Wave Interaction ◽  
Ultrasonic Waves ◽  
Time Harmonic ◽  
Phase And Group Velocities ◽  
Wave Modes

Quantitative ultrasound has shown a significant promise in the assessment of bone characteristics in the recent reports. However, our understanding of wave interaction with bone tissues is still far from complete since the propagation of ultrasonic waves in bones is a very challenging topic due to their multilayer nature. The aim of the current study is to develop a theoretical model for guided waves in a bone-mimicking plate coupled with two soft-tissue layers. Here, the bone plate is modeled as an isotropic solid layer while the soft tissues are modeled as fluid layers. Based on the boundary conditions set for the three-layered structure, a characteristic equation is obtained which results in dispersion curves of the phase and group velocities. New expressions for free guided waves propagating in the trilayered plate are introduced. The amplitudes of wave modes generated by time-harmonic loads applied in the plate are theoretically computed by reciprocity consideration. As an example of calculation, the normalized amplitudes of the lowest wave modes are presented. The obtained results and equations discussed in this study could be, in general, useful for further applications in the area of bone quantitative ultrasound.

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