Bar Diameter

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Paul Anthony Withey - One of the best experts on this subject based on the ideXlab platform.

  • the influence of mould pre heat temperature and casting size on the interaction between a ti 46al 8nb 1b alloy and the mould comprising an al2o3 face coat
    Materials Chemistry and Physics, 2014
    Co-Authors: Xu Cheng, C Yuan, D M Shevchenko, Paul Anthony Withey
    Abstract:

    Abstract Alumina has been used as a mould face coat material for investment casting titanium alloys for many years; the interaction between the Al2O3 and the alloys are exemplified by a hardened layer formed at the alloy interface. In this research, the interaction between the Al2O3 face coat and a Ti–46Al–8Nb–1B alloy was investigated by modelling the cooling profile of the mould during casting. The interaction between the mould and metal was identified from the hardened layer thickness and metal/shell interface microstructural changes. Results showed that a high mould pre-heat temperature and large Bar Diameter will enhance the interaction between the shell and the TiAl alloy. During the casting process, not only was oxygen observed penetrating into the metal through the decomposition of the face coat materials, but also silicon from the backup coat was found to interact with the metal during the casting process.

Zhe Wang - One of the best experts on this subject based on the ideXlab platform.

  • numerical study on seismic behavior of precast bridge columns with large Diameter Bars and uhpc grout considering the Bar slip effect
    Bulletin of Earthquake Engineering, 2020
    Co-Authors: Zhe Wang, Jingqua Wang, Guotang Zhao, Jia Zhang
    Abstract:

    A novel connection adopting lap-spliced large-Diameter Bars and ultra-high performance concrete (UHPC) grout was developed to accelerate the assemble progress of precast bridge columns. The precast bridge column adopting the connections was testified to be on a par with the monolithic concrete counterpart in terms of seismic performance in previous research. This paper aims to develop a numerical model to further investigate the seismic behavior of the proposed bridge column considering the Bar-slip effect. A finite element model was established for the bridge columns considering deformation components of flexure, shear, and Bar-slip. The bond behavior between the deformed Bar and UHPC was defined using a new practical model, which was developed based on a pullout test including five specimens in this research. The established finite element model was verified by the cyclic loading test in literature in terms of the overall hysteretic curve and local responses. The validated model was used to conduct parametric analysis to study the contributions of the different deformation components to lateral deformation as well as the effects of large-Diameter Bars on seismic performance. Results show that all the pullout specimens have the tensile fracture of Bars, which indicates that the development length of 5 times Bar Diameter is sufficient for deformed Bars in UHPC when the Bar Diameter is no more than 32 mm. The practical model is effective to consider the effects of the slip between the deformed Bar and UHPC. The finite element model can predict the overall hysteretic curve and local responses at different drift ratios. The Bar-slip has a considerable even dominative contribution to the lateral deformation of the proposed bridge column. Larger Bar Diameter can enhance deformation capacity as well as reduce energy dissipation and residual drift ratio.

Jia Zhang - One of the best experts on this subject based on the ideXlab platform.

  • numerical study on seismic behavior of precast bridge columns with large Diameter Bars and uhpc grout considering the Bar slip effect
    Bulletin of Earthquake Engineering, 2020
    Co-Authors: Zhe Wang, Jingqua Wang, Guotang Zhao, Jia Zhang
    Abstract:

    A novel connection adopting lap-spliced large-Diameter Bars and ultra-high performance concrete (UHPC) grout was developed to accelerate the assemble progress of precast bridge columns. The precast bridge column adopting the connections was testified to be on a par with the monolithic concrete counterpart in terms of seismic performance in previous research. This paper aims to develop a numerical model to further investigate the seismic behavior of the proposed bridge column considering the Bar-slip effect. A finite element model was established for the bridge columns considering deformation components of flexure, shear, and Bar-slip. The bond behavior between the deformed Bar and UHPC was defined using a new practical model, which was developed based on a pullout test including five specimens in this research. The established finite element model was verified by the cyclic loading test in literature in terms of the overall hysteretic curve and local responses. The validated model was used to conduct parametric analysis to study the contributions of the different deformation components to lateral deformation as well as the effects of large-Diameter Bars on seismic performance. Results show that all the pullout specimens have the tensile fracture of Bars, which indicates that the development length of 5 times Bar Diameter is sufficient for deformed Bars in UHPC when the Bar Diameter is no more than 32 mm. The practical model is effective to consider the effects of the slip between the deformed Bar and UHPC. The finite element model can predict the overall hysteretic curve and local responses at different drift ratios. The Bar-slip has a considerable even dominative contribution to the lateral deformation of the proposed bridge column. Larger Bar Diameter can enhance deformation capacity as well as reduce energy dissipation and residual drift ratio.

Xu Cheng - One of the best experts on this subject based on the ideXlab platform.

  • the influence of mould pre heat temperature and casting size on the interaction between a ti 46al 8nb 1b alloy and the mould comprising an al2o3 face coat
    Materials Chemistry and Physics, 2014
    Co-Authors: Xu Cheng, C Yuan, D M Shevchenko, Paul Anthony Withey
    Abstract:

    Abstract Alumina has been used as a mould face coat material for investment casting titanium alloys for many years; the interaction between the Al2O3 and the alloys are exemplified by a hardened layer formed at the alloy interface. In this research, the interaction between the Al2O3 face coat and a Ti–46Al–8Nb–1B alloy was investigated by modelling the cooling profile of the mould during casting. The interaction between the mould and metal was identified from the hardened layer thickness and metal/shell interface microstructural changes. Results showed that a high mould pre-heat temperature and large Bar Diameter will enhance the interaction between the shell and the TiAl alloy. During the casting process, not only was oxygen observed penetrating into the metal through the decomposition of the face coat materials, but also silicon from the backup coat was found to interact with the metal during the casting process.

Enzo Martinelli - One of the best experts on this subject based on the ideXlab platform.

  • numerical calibration of bond law for gfrp Bars embedded in steel fibre reinforced self compacting concrete
    Composites Part B-engineering, 2013
    Co-Authors: Marco Pepe, Hadi Mazaheripour, Joaquim A O Barros, Jose Senacruz, Enzo Martinelli
    Abstract:

    Abstract An experimental program was carried out at the Laboratory of Structural Division of the Civil Engineering Department of the University of Minho (LEST-UM) to investigate the bond behaviour of glass fibre reinforced polymer (GFRP) Bars embedded in steel fibre reinforced self-compacting concrete (SFRSCC) for the development of an innovative structural system. Thirty-six pull-out-bending tests were executed to assess the influence of the bond length, concrete cover, Bar Diameter and surface treatment on the bond of GFRP Bars embedded in SFRSCC. This paper reports the results of a numerical study aiming to identify an accurate GFRP–SFRSCC bond–slip law. Thus, the above mentioned pullout bending tests were simulated by using a nonlinear finite element (FE) constitutive model available in FEMIX, a FEM based computer program. The bond–slip relationship adopted for modelling the FE interface that simulates the interaction between Bar and concrete is the key nonlinear aspect considered in the FE analyses, but the nonlinear behaviour of SFRSCC due to crack initiation and propagation was also simulated. The evaluation of the values of the relevant parameters defining such a bond–slip relationship was executed by fitting the force versus loaded end slip responses recorded in the experimental tests. Finally, correlations are proposed between the parameters identifying the bond–slip relationship and the relevant geometric and mechanical properties of the tested specimens.

  • experimental study on bond performance of gfrp Bars in self compacting steel fiber reinforced concrete
    Composite Structures, 2013
    Co-Authors: Hadi Mazaheripour, Joaquim A O Barros, Jose Senacruz, Marco Pepe, Enzo Martinelli
    Abstract:

    Abstract Reinforcing Bars made of Glass-Fiber-Reinforced Polymers (GFRPs) are more and more common as internal reinforcement of concrete structures and infrastructures. Since the design of GFRP reinforced concrete members is often controlled by serviceability limit state criteria (i.e. deflection or crack width control), an accurate knowledge of the GFRP-concrete bond behavior is needed to formulate sound design equations. Furthermore, bond laws currently available and widely accepted for conventional steel reBars cannot be straightforwardly applied for GFRP ones. Hence, an experimental program consisting of 36 pullout bending tests was carried out to evaluate the bond performance between GFRP Bars and steel fiber reinforced self-compacting concrete (SFRSCC) by analyzing the influence of the following parameters: GFRP Bar Diameter, surface characteristics of the GFRP Bars, bond length, and SFRSCC cover thickness. Based on the results obtained in this study, pullout failure was occurred for almost all the specimens. SFRSCC cover thickness and bond length plaid important role on the ultimate value of bond stress of GFRP Bars. Moreover, the GFRP Bars with ribbed and sand-coated surface treatment showed different interfacial bond behaviors.