scholarly journals Acoustic Emission Signal Entropy as a Means to Estimate Loads in Fiber Reinforced Polymer Rods

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1089
Author(s):  
Mohammadhadi Shateri ◽  
Maha Ghaib ◽  
Dagmar Svecova ◽  
Douglas Thomson
Keyword(s):  
Acoustic Emission ◽  
Ultimate Load ◽  
Chebyshev’S Inequality ◽  
High Entropy ◽  
Emission Signal ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
The One ◽  
Glass Frp ◽  
Chebyshev's Inequality

Fibre reinforced polymer (FRP) rods are widely used as corrosion-resistant reinforcing in civil structures. However, developing a method to determine the loads on in-service FRP rods remains a challenge. In this study, the entropy of acoustic emission (AE) emanating from FRP rods is used to estimate the applied loads. As loads increased, the fraction of AE hits with higher entropy also increased. High entropy AE hits are defined using the one-sided Chebyshev’s inequality with parameter k = 2 where the histogram of AE entropy up to 10–15% of ultimate load was used as a baseline. According to the one-sided Chebyshev’s inequality, when more than 20% (k = 2) of AE hits that fall further than two standard deviations away from the mean are classified as high entropy events, a new distribution of high entropy AE hits is assumed to exist. We have found that the fraction of high AE hits. In glass FRP and carbon FRP rods, a high entropy AE hit fraction of 20% was exceeded at approximately 40% and 50% of the ultimate load, respectively. This work demonstrates that monitoring high entropy AE hits may provide a useful means to estimate the loads on FRP rods.

Acoustic Emission Signals of Pull-Off Test for Concrete Slab Strengthened with CFRP Using Various Surface Preparations

2019 ◽  
Vol 821 ◽  
pp. 479-485
Author(s):  
Md Nor Noorsuhada ◽  
Mat N. Soffian Noor ◽  
A.M. Siti Norfahanim ◽  
M.H. Mohd Hisbany ◽  
M. Norfaridah
Keyword(s):  
Acoustic Emission ◽  
Concrete Slab ◽  
Surface Preparation ◽  
Signal Strength ◽  
Acoustic Emission Technique ◽  
Normal Surface ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Concrete Interface

This study investigates the acoustic emission signals of concrete slab strengthened with carbon fibre reinforced polymer (CFRP) under pull-off test. Three types of surface preparations were prepared namely without surface preparation, normal surface preparation and boring surface preparation. The slabs were then tested under pull-off test in conjunction with acoustic emission technique. The pull-off strength, acoustic signal strength, amplitude, duration and rise time were analysed and discussed. It was found that the boring surface preparation produced the highest pull-off strength compared to other surface preparations, indicating good bonding between the CFRP and the concrete interface. This study is useful in identifying the bonding between CFRP and concrete using acoustic emission technique.

scholarly journals Strengthening of self-compacting reinforced concrete deep beams containing circular openings with CFRP

2018 ◽  
Vol 162 ◽  
pp. 04015
Author(s):  
Nabeel Al-Bayati ◽  
Bassman Muhammad ◽  
Murooj Faek
Keyword(s):  
Ultimate Load ◽  
Test Results ◽  
Load Path ◽  
Deep Beams ◽  
Self Compacting Concrete ◽  
Reinforced Polymer ◽  
Web Reinforcement ◽  
Externally Bonded ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer

This paper shows the behavior of reinforced self-compacting concrete deep beams with circular openings strengthened in shear with various arrangements of externally bonded Carbon Fibre Reinforced Polymer (CFRP). Six simply supported deep beams were constructed and tested under two points load up to the failure for this purpose. All tested beams had same geometry, compressive strength, shear span to depth ratio, main flexural and web reinforcement. The variables considered in this study include the influence of fiber orientation, utilizing longitudinal CFRP strips with vertical strips and area of CFRP. The test results indicated that the presence of the circular openings in center of load path reduce stiffness and ultimate strength by about 50% when compared with solid one, also it was found that the externally bonded CFRP can significantly increase the ultimate load and enhance the stiffness of deep beam with openings.

scholarly journals Studies on stress-strain behaviour of concrete mixes confined with BFRP rebars

2021 ◽  
Vol 309 ◽  
pp. 01049
Author(s):  
K Ajay Kumar ◽  
A Venkat Sai Krishna ◽  
S Shrihari ◽  
V Srinivasa Reddy
Keyword(s):  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Basalt Fibre ◽  
Stress Strain ◽  
Reinforced Polymer ◽  
Strain Behaviour ◽  
Load Carrying ◽  
Fibre Reinforced Polymer ◽  
Ultimate Load Carrying Capacity ◽  
Steel Rebars

In the present study, the stress-stain behaviour of confined concrete made with basalt fibre reinforced polymer bars (BFRP) were taken up. The stress-strain behaviour was studied for the concrete mixes confined with steel rebars and BFRP rebars. The confinement was given in the form of steel hoops in the cylinders, 3 hoops (0.8%), 4 hoops (1.1%), 5 hoops (1.3%) and 6 hoops (1.6%). The addition of basalt fibres along with confinement of concrete with steel and BFRP hoops enhanced the compressive strength, indicating further confinement effect in the concrete. It is observed that the addition of fibres is helpful in lower confinements only. Beyond 1.1% confinement, the addition of any type of basalt fibres doesn’t show any effect on compressive strengths. From the stress-strain behaviour of all types of concrete mixes, it is concluded that the ultimate load-carrying capacity and strains at peak stresses are more in concrete with BFRP hoops for mixes up to 1.1% confinement. The addition of basalt fibres to concrete has increased the ductility in both confined and unconfined states

scholarly journals Comparison of the Flexural Performance and Behaviour of Fly-Ash-Based Geopolymer Concrete Beams Reinforced with CFRP and GFRP Bars

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Hemn Qader Ahmed ◽  
Dilshad Kakasor Jaf ◽  
Sinan Abdulkhaleq Yaseen
Keyword(s):  
Crack Width ◽  
Ultimate Load ◽  
Load Capacity ◽  
Reinforcement Ratio ◽  
Geopolymer Concrete ◽  
Ultimate Load Capacity ◽  
Gfrp Bars ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Frp Bars

A construction system with high sustainability, high durability, and appropriate strength can be supplied by geopolymer concrete (GPC) reinforced with glass fibre-reinforced polymer (GFRP) bars and carbon fibre-reinforced polymer (CFRP) bars. Few studies deal with a combination of GPC and FRP bars, especially CFRP bars. The present investigation presents the flexural capacity and behaviour of fly-ash-based GPC beam reinforced with two different types of FRP bars: six reinforced geopolymer concrete (RGPC) beams consisting of three specimens reinforced with GFRP bars and the rest with CFRP bars. The beams were tested under four-point bending with a clear span of 2000 mm. The test parameters included the longitudinal-reinforcement ratio and the longitudinal-reinforcement type, including GFRP and CFRP. Ultimate load, first crack load, load-deflection behaviour, load-strain curve, crack width, and the modes of failure were studied. The experimental results were compared with the equations recommended by ACI 440.1R-15 and CSA S806-12 for flexural strength and midspan deflection of the beams. The results show that the reinforcement ratio had a significant effect on the ultimate load capacity and failure mode. The ultimate load capacity of CFRP-RGPC beams was higher than that of GFRP-RGPC, more crack formations were observed in the CFRP-RGPC beams than in the GFRP-RGPC beams, and the crack width in the GFRP-RGPC beams was more extensive than that in the CFRP-RGPC beams. Beams with lower reinforcement ratios experienced a fewer number of crack and a higher value of crack width, while numerous cracks and less value of crack width were observed in beams with higher reinforcement ratio. Beams with the lower reinforcement ratios were more affected by the type of FRP bars, and the deflection in GFRP-RGPC beams was higher than that in CFRP-RGPC beams for the same corresponding load level. ACI 440.1R-15 and CSA S806-12 underestimated the flexural strength and midspan deflection of RGPC beams; however, CSA S806-12 predicted more accurately.

Flexural and axial behaviour of sandwich panels with bio-based flax fibre-reinforced polymer skins and various foam core densities

2016 ◽  
Vol 20 (5) ◽  
pp. 595-616 ◽  
Author(s):  
Luke CoDyre ◽  
Kenneth Mak ◽  
Amir Fam
Keyword(s):  
Sandwich Panels ◽  
Single Layer ◽  
Flax Fibre ◽  
Foam Core ◽  
Core Density ◽  
Axial Capacity ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Stub Column ◽  
Glass Frp

This study investigates the effect of foam core density on the behaviour of sandwich panels with novel bio-composite unidirectional flax fibre-reinforced polymer skins, along with a comparison to panels of conventional glass-FRP skins. Eighteen 1000 mm long flexural specimens and 18 500 mm long stub column specimens were fabricated and tested. All specimens had a foam core of 100 × 50 mm2 cross-section with symmetrical 100 mm wide skins. The study compares the effect of three separate polyisocyanurate foam cores when used in conjunction with either three layers of flax fibre-reinforced polymer or a single glass-FRP layer for each skin. Flexural specimens were tested in four-point bending and stub columns were tested under axial compression with pin–pin end conditions. Doubling the core density from 32 to 64 kg/m3 and tripling the density to 96 kg/m3 led to flexural strength increases of 82 and 213%, respectively, for flax fibre-reinforced polymer skinned panels, and comparable increases in glass-FRP skinned panels. Similarly, flax fibre-reinforced polymer-skinned columns showed similar increases in ultimate axial capacity of 85% and 196%, while glass-FRP- skinned columns experienced lower increases when core density was varied. The three-layered flax fibre-reinforced polymer skin, only 17% thicker than the single layer glass-FRP skin, was shown to provide equivalent flexural and axial strengths at all three core densities, within −5 to +13%.

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