Monitoring internal corrosion in steel pipelines: a two-step helical guided wave approach for localization and quantification

2020 ◽  
pp. 147592172097013
Author(s):  
Stylianos Livadiotis ◽  
Arvin Ebrahimkhanlou ◽  
Salvatore Salamone
Keyword(s):  
Eikonal Equation ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Energy Ratio ◽  
Reconstruction Technique ◽  
Accelerated Corrosion ◽  
Internal Corrosion ◽  
Cylindrical Structures ◽  
Damage Coefficient ◽  
Accelerated Corrosion Test

This article presents a two-step approach for the assessment of internal corrosion in cylindrical structures using helical guided ultrasonic waves. The approach consists of two steps such as (1) localization and (2) estimation of the size of the corroded area. Localization is performed with the algebraic reconstruction technique where the energy ratio of the two fundamental Lamb modes S0 and A0 is used as input damage coefficient. Using the output of the localization step, the size of the corroded area is estimated by iteratively solving the eikonal equation using a finite-difference approach. The proposed approach is validated by an accelerated corrosion test. Furthermore, numerical simulations are carried out to study the interaction of the energy ratio and the phase velocity travel time with various thickness profiles acquired from the experiment. The proposed approach is validated against the experimental data up to approximately 50% thickness loss.

scholarly journals Vehicle accelerated corrosion test procedures for automotive in Malaysia

2016 ◽  
Vol 90 ◽  
pp. 01040 ◽  
Author(s):  
Liza Anuar ◽  
Astuty Amrin ◽  
Roslina Mohammad ◽  
Ali Ourdjini
Keyword(s):  
Corrosion Test ◽  
Test Procedures ◽  
Accelerated Corrosion ◽  
Accelerated Corrosion Test

Study on Corrosion Damage Rule for Two Type of Aluminum Alloy

2014 ◽  
Vol 599-601 ◽  
pp. 111-113
Author(s):  
Dan Feng Zhang ◽  
Xiao Ming Tan ◽  
Dan Gui Zhang ◽  
Fang Zhang ◽  
Wei Zhang
Keyword(s):  
Aluminum Alloy ◽  
Statistical Analysis ◽  
Marine Environment ◽  
Corrosion Test ◽  
Corrosion Damage ◽  
Aircraft Structure ◽  
Accelerated Corrosion ◽  
Damage Repair ◽  
Accelerated Corrosion Test ◽  
Damage Rule

Corrosion exists everywhere. It’s very widespread that the aluminum alloy aircraft structure suffers the corrosion damage under the marine environment particularly. The equivalent accelerated corrosion test of the new aluminum alloy 2B06 and 7B04 was carried out.Corrosion damage was inspected and measured through microscope. The rule of the corrosion damage can be obtained by statistical analysis. And which can supply the reference basis for the corrosion damage repair and evaluating the calendar life.

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 Corrosion Prevention on Coated Rebars and Fiber in R.C Slabs

2018 ◽  
Vol 7 (3.34) ◽  
pp. 36
Author(s):  
Dr M.Tamil Selvi ◽  
Ms. J Hathari Evangalin ◽  
M.s S. Gayathri
Keyword(s):  
Research Work ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Accelerated Corrosion ◽  
Structural Problems ◽  
Nylon Fiber ◽  
Cell Measurement ◽  
Accelerated Corrosion Test ◽  
Rc Slabs ◽  
Corrosion Of Steel

Concrete structures prevail primarily due to prior attrition of steel due to preterm failure of rebars. The major cause of deterioration is the corrosion of the steel reinforcement, that can lead to structural problems. By utilizing our knowledge on corrosion of steel reinforcement, concrete structures could be made more durable. The research work is intend at arrestcorrosion in RC slabs by glazing silicon tombac to the steel rods. Nylon fiber is induced in concrete to attain strength for the concrete. A study report carried the effects of coating material between the conventional and fibers in concrete was compared with that of uncoated material between the conventional and fiber in concrete rebar’s. A continuous corrosion process is accelerated by inducing direct current to rebars. Process used to prompt corrosion is Accelerated corrosion test and Half-cell measurement.  

scholarly journals Improving sensitivity and coverage of structural health monitoring using bulk ultrasonic waves

2020 ◽  
pp. 147592172096512
Author(s):  
Stefano Mariani ◽  
Yuan Liu ◽  
Peter Cawley
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Temperature Compensation ◽  
Signal Amplitude ◽  
Guided Wave ◽  
Ultrasonic Waves ◽  
Back Wall ◽  
Environmental Chamber ◽  
Structural Health ◽  
Specific Temperature

Practical ultrasonic structural health monitoring systems must be able to deal with temperature changes and some signal amplitude/phase drift over time; these issues have been investigated extensively with low-frequency-guided wave systems but much less work has been done on bulk wave systems operating in the megahertz frequency range. Temperature and signal drift compensation have been investigated on a thick copper block specimen instrumented with a lead zirconate titanate disc excited at a centre frequency of 2 MHz, both in the laboratory at ambient temperature and in an environmental chamber over multiple 20°C–70°C temperature cycles. It has been shown that the location-specific temperature compensation scheme originally developed for guided wave inspection significantly out-performs the conventional combined optimum baseline selection and baseline signal stretch method. The test setup was deliberately not optimised, and the signal amplitude and phase were shown to drift with time as the system was temperature cycled in the environmental chamber. It was shown that the ratio of successive back wall reflections at a given temperature was much more stable with time than the amplitude of a single reflection and that this ratio can be used to track changes in the reflection coefficient from the back wall with time. It was also shown that the location-specific temperature compensation method can be used to compensate for changes in the back wall reflection ratio with temperature. Clear changes in back wall reflection ratio were produced by the shadow effect of simulated damage in the form of 1-mm diameter flat-bottomed holes, and the signal-to-noise ratio was such that much smaller defects would be detectable.

scholarly journals Experimental Study on Corrosion and Mechanical Behavior of Main Cable Wires Considering the Effect of Strain

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 753 ◽  
Author(s):  
Fangyuan Xu ◽  
Yuanli Chen ◽  
Xianglong Zheng ◽  
Rujin Ma ◽  
Hao Tian
Keyword(s):  
Elastic Modulus ◽  
Mass Loss ◽  
Stress Level ◽  
Corrosion Test ◽  
Ultimate Load ◽  
Cross Sectional ◽  
Accelerated Corrosion ◽  
Yield Load ◽  
Accelerated Corrosion Test ◽  
Corrosion Time

To study the corrosion degradation of cable wires in a bridge’s life, this research work created an accelerated corrosion test device, which sought to identify an optimal constant strain level. An accelerated corrosion test was carried out and the corroded specimens were scanned using super depth 3D microscopy technology. Mass loss and minimum cross-sectional diameter was measured to understand the degradation characteristics of cable wires at variable strains and corrosion time. The variation of elastic modulus, yield load, and ultimate load of corroded wires, subjected to a tensile test, were analyzed. The experimental results illustrate that the average mass loss ratio of the corroded cable wires increases nonlinearly as corrosion time increases. The higher the stress level, the more serious the corrosion level. The minimum cross-sectional diameter has good correlation with corrosion time and stress level. The elastic modulus of wires does not change significantly with the increase of corrosion time. Yield load and ultimate load decreases with the increase of strain level, and the rates of decline under different strains are nonlinear.

Sign in / Sign up

Export Citation Format

Share Document