An improved discrete elliptic imaging algorithm based on guided waves for defect localisation in curved plates

2019 ◽  
Vol 61 (11) ◽  
pp. 656-662
Author(s):  
Gangyi Hu ◽  
Shaojie Chen ◽  
Chaofeng Chen ◽  
Shuangmiao Zhai ◽  
Shaoping Zhou
Keyword(s):  
Flat Plate ◽  
Guided Waves ◽  
Experimental Results ◽  
Circular Array ◽  
Improved Method ◽  
Plate Structures ◽  
Imaging Algorithm ◽  
Single Defect ◽  
Normalisation Method

Many effective image-based algorithms are available for detecting and locating defects in flat plate-like structures. However, there are few studies on image-based algorithms for curved plate structures. An improved method is proposed in this article, which is based on the discrete elliptic imaging algorithm and the improved signal normalisation method. To verify its effectiveness, experiments using a circular array are conducted on curved plates with different degrees of bending. The experimental results show that the improved method can accurately locate defects in curved plates and, compared with the original discrete elliptic imaging algorithm, its range of error in locating a single defect is reduced from 20.2-33.3 mm to 2.7-5.1 mm.

scholarly journals A Generalized Method for Flat Plates Impact Detection and Location

2013 ◽  
Vol 543 ◽  
pp. 171-175
Author(s):  
Jose Andrés Somolinos ◽  
Rafael Morales ◽  
Carlos Morón ◽  
Alfonso Garcia
Keyword(s):  
Signal Processing ◽  
Flat Plate ◽  
Acoustic Signal ◽  
Experimental Results ◽  
Piezoelectric Sensors ◽  
Experimental Setup ◽  
Flat Plates ◽  
Impact Detection ◽  
Timing Difference

In the last years, many analyses from acoustic signal processing have been used for different applications. In most cases, these sensor systems are based on the determination of times of flight for signals from every transducer. This paper presents a flat plate generalization method for impact detection and location over linear links or bars-based structures. The use of three piezoelectric sensors allow to achieve the position and impact time while the use of additional sensors lets cover a larger area of detection and avoid wrong timing difference measurements. An experimental setup and some experimental results are briefly presented.

Effect of plasma actuator in boundary layer on flat plate model with turbulent promoter

2017 ◽  
Vol 232 (16) ◽  
pp. 3001-3010
Author(s):  
James Julian ◽  
Harinaldi ◽  
Budiarso ◽  
Chin-Cheng Wang ◽  
Ming-Jyh Chern
Keyword(s):  
Boundary Layer ◽  
Flat Plate ◽  
Aerodynamic Drag ◽  
Active Flow Control ◽  
Adverse Pressure Gradient ◽  
Plasma Actuator ◽  
Experimental Results ◽  
Plate Model ◽  
Displacement Thickness ◽  
Turbulent Promoter

This paper shows experimental results for velocity measurement in the boundary layer with the use of a flat plate model. The flat plate model is disrupted with a wire trip and the effect of the plasma actuator to alter the flow in the boundary layer is then observed. The purpose of this research is to characterize the performance of the plasma actuator in a no-flow condition and with the use of a 2 m/s flow and also to theoretically analyze the performance of actuator in the boundary layer namely, displacement thickness, momentum thickness, and energy thickness. This is all done to acquire a deeper understanding of the capabilities of plasma actuator as one of the alternative active flow control equipment and to increase the effect of aerodynamic drag reduction. One of the ways to decrease the aerodynamic drag is to manipulate the flow to have a low boundary layer thickness value in order to prevent an adverse pressure gradient from happening, which then may lead to the formation of a flow separation. From experimental results, it is known that plasma actuator could decrease the thickness of the boundary layer by 9 mm.

scholarly journals Evaluating the Performance of Two Solar Domestic Hot Water Systems of the Archetype Sustainable Houses

2021 ◽  
Author(s):  
Kamyar Tanha
Keyword(s):  
Flat Plate ◽  
Hot Water ◽  
Experimental Results ◽  
Solar Thermal ◽  
Energy Output ◽  
Evacuated Tube Collector ◽  
Solar Thermal Collector ◽  
Solar Thermal Collectors ◽  
Evacuated Tube Collectors ◽  
Evacuated Tube

This thesis is focused on the performance of the two SDHW systems of the sustainable Archetype houses in Vaughan, Ontario with daily hot water consumption of 225 litres. The first system consists of a flat plate solar thermal collector in conjunction with a gas boiler and a DWHR. The second SDHW system consists of an evacuated tube collector, an electric tank and a DWHR. The experimental results showed that the DWHRs were capable of an annual heat recovery of 789 kWh. The flat plate and evacuated tube collectors had an annual thermal energy output of 2038 kWh and 1383 kWh. The systems were also modeled in TRNSYS and validated with the experimental results. The simulated results showed that Edmonton has the highest annual energy consumption of 3763.4 kWh and 2852.9 kWh by gas boiler and electric tank and that the solar thermal collectors and DWHRs are most beneficial in Edmonton.

Behaviors of Repaired Edge Column Slab Connections after Punching Failure Using Normal and Non-Shrinkable (CAH) Concrete

2016 ◽  
Vol 845 ◽  
pp. 166-174
Author(s):  
I. Ketut Sudarsana
Keyword(s):  
Flat Plate ◽  
Punching Shear ◽  
Normal Concrete ◽  
Plate Structures ◽  
Shear Damage ◽  
Concrete Mix ◽  
Surface Confinement ◽  
Strength And Stiffness ◽  
Original Strength ◽  
Punching Failure

Column slab connections in flat plate structures are critical part of the structure. Punching shear damage to the connections may occur during construction or post moderate earthquakes. To avoid demolishing overall structures with such damage, connections may be repaired to restore the original strength of the structures. This paper presents behavior of repaired edge column slab connections using normal concrete and non-shrinkable (CAH) concrete. Four edge connections of flat plate structure after failure were repaired using normal and non-shrinkable (CAH) concrete respectively for two connections. The connections were re-tested to fail under combined shear and moment. The results show that bonding agent Sika Top Armatec 110 Epocem gave an excellent bond between the old concrete and the repaired concrete in the tests of repaired edge column slab connection as there are no cracks observed along the concrete interface. The edge connections repaired using normal concrete can have similar strength and stiffness as the original connections when good curing is provided The edge connections repaired using an expansive CAH concrete exhibited less strength and stiffness compared to the original edge connections due to lack of surface confinement. The Superplasticizer used in CAH concrete (Mix. B) improves concrete expansion but reduce the strength of the repaired connections

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.

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