http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Experimental Study of Intermediate Length Coupling Beams subjected to Monotonic Load
Abu Bakar Nabilah,Chan Ghee Koh 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.7
Experimental study is conducted on four reinforced concrete coupling beams, with length to depth ratios of 2.5 and 3.1. The beams are designed to fail in shear after yielding of longitudinal reinforcement. The longitudinal reinforcement contents are 0.76 and 1.14 percent, while shear reinforcement varies from 0.2 to 0.5 percent. The beams are loaded monotonically until failure. It is found that the shear stiffness of such beams reduces to 0.1 of the initial stiffness upon yielding of reinforcement. An empirical equation is proposed to assess the shear strength degradation of the beams based on axial strain of longitudinal reinforcement.
Abu Bakar Nabilah,Chan Ghee Koh,Abd. Karim Izian,Farah Nora Aznieta Abd. Aziz 한국콘크리트학회 2020 International Journal of Concrete Structures and M Vol.14 No.5
Finite element analysis is performed on four reinforced concrete coupling beams of intermediate length using 2-D plane stress elements, under monotonic load up to failure. The model is verified using the results from (Nabilah and Koh in KSCE J Civil Eng 21:2807–2813, 2017). The bond-slip interface for the longitudinal reinforcement is modeled in the finite element, as it is found that it better predicts the load-deformation behavior compared to perfect bond. The comparison between finite element analysis and the experiment found that the model is able to predict the overall behavior of the structure, especially the maximum load capacity. The maximum deformation and the shear deformation from the finite element analysis are found to be underestimated, due to the inability of the model to predict shear deformation accurately. Flexural deformation (due to flexure and slip) is found to be well predicted, as the bond-slip behavior is modeled in the analysis. Generally, the shear deformation and slip are found to be significant in the intermediate length coupling beam and should not be ignored in the analysis. Finally, the effective stiffness prediction using finite element analysis is found to be overestimated and should be determined instead using existing equations.
Study on the influence mechanism of sintering hydroxyapatite (HA)
Nabilah Afiqah Mohd Radzuan,Abu Bakar Sulong,Farhana Mohd Foudzi,Mohd Yusuf Zakaria,Mohd Ikram Ramli 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.6
As one of promising biomaterial, hydroxyapatite (HA) is potentially used as an implant component. Yet, to date, HA stillencounter difficulties to be comerciallise due to the easily deteriorate and often fluctuate mechanical performance whichdepends on the manufacturing process. Thus, this study aims to experiment the influence of HA composition and sinteringparameter on the densification, morphological analysis and flexural strength in terms of green parts and sintered HA. The HAparts are fabricated through the powder injection moulding process with the pressure applied between 10 and 12 bar at 150 oC. The HA compositions are varied of 54 wt.%, 55 wt.% and 56 wt.% while the sintering parameter are set at 1,100 oC, 1,200 oCand 1,300 oC. The 56 wt.% of HA parts recorded the densification of 2.13 g/cm3 and 2.95 g/cm3 for both green parts andsintered parts at 1,300 oC. However, as the sintering temperature reduced to 1,200 oC, the densification reached the value of2.9 g/cm3 with the existence of porous structure to allow tissue growth. This finding suggested that the HA parts can be massproduce using powder injection moulding process at 1,200 oC, with a minimum existence of porosity to allow tissue growth inbetween the HA structure.
Thermal Resistance of Insulated Precast Concrete Sandwich Panels
Sani Mohammed Bida,Farah Nora Aznieta Abdul Aziz,Mohd Saleh Jaafar,Farzad Hejazi,Nabilah Abu Bakar 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.6
Many nations are already working toward full implementation of energy efficiency in buildings known as Green Building. In line with this perspective, this paper aims to develop a thermally efficient precast concrete sandwich panels (PCSP) for structural applications. Therefore, an experimental investigation was carried out to determine the thermal resistance of the proposed PCSP using Hotbox method and the results were validated using finite element method (FEM) in COMSOL Multiphysics Software. The PCSP were designed with staggered shear connectors to avoid thermal bridges between the successive layers. The staggered connectors are spaced at 200 mm, 300 mm and 400 mm on each concrete layer, while the control panel is designed with 200 mm direct shear connection. In the experimental test, four (4) panels of 500 mm × 500 mm and 150 mm thick were subjected to Hotbox Test to determine the thermal resistance. The result shows that thermal resistance of the PCSP with staggered shear connection increases with increase in spacing. The PCSP with 400 mm staggered shear connectors indicates the best thermal efficiency with a thermal resistance (R value) of 2.48 m²K/W. The thermal performance was verified by FEA which shows less than 5% error coupled with a precise prediction of surface temperature gradient. This indicates that, with conventional materials, thermal path approach can be used to develop a precast concrete building with better thermal resistant properties. Hopefully, stakeholders in the green building industry would find this proposed PCSP as an alternative energy efficient load bearing panel towards sustainable and greener buildings.