The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
D.m. Imani - One of the best experts on this subject based on the ideXlab platform.
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On the use of edge cracked short bend Beam Specimen for PMMA fracture toughness testing under mixed-mode I/II
Polymer Testing, 2020Co-Authors: S.s. Mousavi, M.r.m. Aliha, D.m. ImaniAbstract:Abstract In this paper an inclined edge cracked short Beam Specimen subjected to symmetric three-point bend loading was designed and examined for conducting mixed-mode I/II fracture toughness experiments. The aspect ratio (i.e. length to width ratio) and the loading span distance are considered much lower than the other conventional cracked bend Beam samples. Crack tip parameters such as stress intensity factors and T-stress were computed numerically for this Specimen by several finite element analyses and it was demonstrated that the Specimen is able to produce full combinations of mode I and II including pure mode II. The practical capability of the short bend Beam Specimen was studied experimentally by conducting a set of mixed-mode fracture tests on PolymethylMethacrylate (PMMA) as a well-known model brittle material. The critical stress intensity factors, the direction of fracture kinking and the path of fracture trajectory were investigated both experimentally and theoretically using two stress and strain-based fracture criteria. The fracture toughness of tested PMMA was decreased by moving towards mode II case due to the effect of T-stress on the fracture mechanism of the short bend Beam Specimen.
Pradeep Bhargava - One of the best experts on this subject based on the ideXlab platform.
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Bond Slip Study Between Concrete and Steel Interface Using Splice Beam Specimen Exposed to Elevated Temperatures
Structures, 2020Co-Authors: Mohammad Suhaib Ahmad, Pradeep BhargavaAbstract:Abstract Bond stress-slip behavior between the reinforcing steel and the concrete is one of the basic properties which influences the performance of the structure at the serviceability as well as at the ultimate limit state. However, this behavior changes with the exposure to elevated temperatures. Bond slip behavior after exposure to elevated temperatures have been studied using pull out Specimens because of its ease of operation and economy. These Specimens do not simulate the actual state of bond stress in reinforced concrete structures during testing. Therefore, an experimental study was conducted to investigate the effect of elevated temperatures on the bond behavior between reinforcing steel and concrete using splice Beam Specimen. The Specimens were heated to three temperatures of 350 °C, 550 °C and 750 °C inside the furnace at a rate of 5 °C/min till the desired temperatures are achieved. The Specimens were tested under four point bending to obtain i) relative slip between steel and concrete, ii) strain in the reinforcing bar and iii) mid span deflection of the Beam Specimens. The results show that the bond stress between reinforcing steel and concrete decreases after the exposure to elevated temperature while there relative slip increases. The reduction in bond stress is significant after the exposure to 550 °C. The reduction in the bond strength at a temperature is directly proportional to the reduction of its compressive strength at that temperature. A shift in the failure mode was observed in the Beam Specimens from a more brittle to a gradual failure after the exposure to 550 °C. Prediction of the bond strength for the Beam Specimens after elevated temperatures were also made using elastic, plastic and elastoplastic analysis based on thick wall cylinder theory. The analysis shows that the prediction based on plastic analysis overestimates the bond strength at elevated temperatures while the elastic and elastoplastic analysis shows conservative results. Based on the analysis, a model is proposed, which can predict the bond strength of splice Beam Specimens after exposure to elevated temperatures with considerably good efficiency.
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Study on bond behaviour exposed to fire using Beam Specimen
IOP Conference Series: Earth and Environmental Science, 2018Co-Authors: Mohammad Suhaib Ahmad, Pradeep Bhargava, Umesh Kumar SharmaAbstract:The composite action of concrete and steel in a reinforced concrete structure depends upon the bond between them. Bond behaviour is studied in terms of bond-slip relationship. The bond between them depends upon mechanical properties of concrete and steel. In an event of fire these mechanical properties degrades and hence the bond behaviour changes. Some researches were performed to study the effect of temperature on the bond-slip relationship which are based on pull out Specimens. Generally these relationships are obtained using pull out Specimen which over estimates the bond properties. In this study Beam Specimens were used which is recommended by Rilem. These Specimens were exposed to elevated temperatures up to 650 °C and there bond-slip behaviour were studied. The study shows that bond strength decreases while peak slip increases with increases in temperature. Also an equation proposed was proposed which can predict the bond strength between concrete and steel exposed up to the temperature of 650 °C.
Farid Taheri - One of the best experts on this subject based on the ideXlab platform.
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Fracture response of double cantilever Beam subject to thermal fatigue
Journal of Strain Analysis for Engineering Design, 2018Co-Authors: Mbarka Mohamed, Farid TaheriAbstract:When adhesively bonded joints undergo thermal fluctuations, they become fatigued and suffer mechanical degradation. A comprehensive experimental investigation is conducted to examine the performance and degradation of adhesively bonded joints, in the form of the standard double cantilever Beam Specimen, subject to various levels of cyclic thermal loadings. Results indicate that regardless the number of applied thermal cycles, the joint experiences degradation of its interface adhesive, and that the degradation evolves as the number of thermal cycles increases, leading to the gradual degradation of the overall interface strength. Also, a computational framework, using the cohesive zone modeling technique, is developed for predicting the growth of a crack under the thermal and subsequent mechanical loadings. The good agreement observed between the computational and experimental results validates the integrity of the developed computational framework.
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an effective means for evaluating mixed mode i iii stress intensity factors using single edge notch Beam Specimen
Journal of Strain Analysis for Engineering Design, 2013Co-Authors: Babak Ahmadimoghadam, Farid TaheriAbstract:The main objective of this study is to produce a set of practical equations, by which one could evaluate mixed-mode I/III stress intensity factors by conducting a simple mode I single-edge notch be...
Sami F. Masri - One of the best experts on this subject based on the ideXlab platform.
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Performance of embedded short-gage-length optical fiber sensors in a fatigue-loaded reinforced concrete Specimen
Smart Materials and Structures, 1995Co-Authors: M De Vries, Manish H. Nasta, Vikram Bhatia, Tuan A. Tran, Jonathan A. Greene, Richard O. Claus, Sami F. MasriAbstract:This paper reports the performance of short-gage-length optical fiber sensors embedded in a reinforced concrete Specimen. Embedded extrinsic Fabry-Perot optical fiber sensors, attached to steel reinforcement rods, were used to monitor local displacements and strain in a concrete cross-Beam Specimen. The strain data obtained from the fiber sensors were compared with data obtained from collocated foil strain gages. Absolute extrinsic Fabry-Perot interferometric sensors, capable of measuring absolute displacement and strain, were embedded in a steel-reinforced concrete Specimen. Loading experiments performed on this Specimen also yielded absolute strain information. The Specimen was cyclically loaded for more than 100000 cycles in this geometry and the sensors still provided quantitative strain information regarding this Specimen.
Mohammad Suhaib Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Bond Slip Study Between Concrete and Steel Interface Using Splice Beam Specimen Exposed to Elevated Temperatures
Structures, 2020Co-Authors: Mohammad Suhaib Ahmad, Pradeep BhargavaAbstract:Abstract Bond stress-slip behavior between the reinforcing steel and the concrete is one of the basic properties which influences the performance of the structure at the serviceability as well as at the ultimate limit state. However, this behavior changes with the exposure to elevated temperatures. Bond slip behavior after exposure to elevated temperatures have been studied using pull out Specimens because of its ease of operation and economy. These Specimens do not simulate the actual state of bond stress in reinforced concrete structures during testing. Therefore, an experimental study was conducted to investigate the effect of elevated temperatures on the bond behavior between reinforcing steel and concrete using splice Beam Specimen. The Specimens were heated to three temperatures of 350 °C, 550 °C and 750 °C inside the furnace at a rate of 5 °C/min till the desired temperatures are achieved. The Specimens were tested under four point bending to obtain i) relative slip between steel and concrete, ii) strain in the reinforcing bar and iii) mid span deflection of the Beam Specimens. The results show that the bond stress between reinforcing steel and concrete decreases after the exposure to elevated temperature while there relative slip increases. The reduction in bond stress is significant after the exposure to 550 °C. The reduction in the bond strength at a temperature is directly proportional to the reduction of its compressive strength at that temperature. A shift in the failure mode was observed in the Beam Specimens from a more brittle to a gradual failure after the exposure to 550 °C. Prediction of the bond strength for the Beam Specimens after elevated temperatures were also made using elastic, plastic and elastoplastic analysis based on thick wall cylinder theory. The analysis shows that the prediction based on plastic analysis overestimates the bond strength at elevated temperatures while the elastic and elastoplastic analysis shows conservative results. Based on the analysis, a model is proposed, which can predict the bond strength of splice Beam Specimens after exposure to elevated temperatures with considerably good efficiency.
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Study on bond behaviour exposed to fire using Beam Specimen
IOP Conference Series: Earth and Environmental Science, 2018Co-Authors: Mohammad Suhaib Ahmad, Pradeep Bhargava, Umesh Kumar SharmaAbstract:The composite action of concrete and steel in a reinforced concrete structure depends upon the bond between them. Bond behaviour is studied in terms of bond-slip relationship. The bond between them depends upon mechanical properties of concrete and steel. In an event of fire these mechanical properties degrades and hence the bond behaviour changes. Some researches were performed to study the effect of temperature on the bond-slip relationship which are based on pull out Specimens. Generally these relationships are obtained using pull out Specimen which over estimates the bond properties. In this study Beam Specimens were used which is recommended by Rilem. These Specimens were exposed to elevated temperatures up to 650 °C and there bond-slip behaviour were studied. The study shows that bond strength decreases while peak slip increases with increases in temperature. Also an equation proposed was proposed which can predict the bond strength between concrete and steel exposed up to the temperature of 650 °C.