This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pi...This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pipe(CFUT)with different geometric properties were tested.To obtain the specimens different class pipes with three different diameters were used to investigate the sensitivity of these columns to various parameters.The effect of each variable on the ultimate strength,ductility and confinement efficiency of the samples was investigated.All specimens were compressed by applying load only to the concrete core to obtain the load-displacement variations and the corresponding deformation mode.A finite element model was developed using the proposed stress-strain variation of confined concrete with UPVC tubes to simulate axial compression of CFUT specimens.According to the results obtained,the effect of the change in diameter-thickness ratio failure stress of concrete limited by(D/t)is obtained and discussed with empirical relationship.Polypropylene fibers were found to slightly increase column strength up to a certain volume fraction,after which the strength generally experienced a decrease.展开更多
The flow process of unplasticized polyvinyl chloride （U PVC） through the mixing zone of intermeshing counter rotating and co rotating twin screw extruders （TSEs） were numerically simula ted by the finite element m...The flow process of unplasticized polyvinyl chloride （U PVC） through the mixing zone of intermeshing counter rotating and co rotating twin screw extruders （TSEs） were numerically simula ted by the finite element method. Three dimensional isothermal flow field of U-PVC in two kinds of TSE was calculated. The mixing performance of the screw elements of the extruders was statistically analyzed by particle tracking method. The dispersive mixing performance was characterized by the mixing index, the logarithm of stretching, and the segregation scale. The distributive mixing per forulance was characterized by the resident time distribution. The results indicate that the counter rotating TSE can build higher pressure and generate higher axial velocity and shear rate, whereas the co rotating TSE has better performance in dispersive and distributive mixing.展开更多
基金the Head of the Civil Engineering Department,Faculty of Engineering and Technology,Jamia Millia Islamia,New Delhi-110025,India.
文摘This article aims to examine the behavior of Unplasticized Poly-Vinyl-Chloride(UPVC)bounded reinforced columns with polypropylene fibers under axial compression.To develop this model,samples of concrete filled UPVC pipe(CFUT)with different geometric properties were tested.To obtain the specimens different class pipes with three different diameters were used to investigate the sensitivity of these columns to various parameters.The effect of each variable on the ultimate strength,ductility and confinement efficiency of the samples was investigated.All specimens were compressed by applying load only to the concrete core to obtain the load-displacement variations and the corresponding deformation mode.A finite element model was developed using the proposed stress-strain variation of confined concrete with UPVC tubes to simulate axial compression of CFUT specimens.According to the results obtained,the effect of the change in diameter-thickness ratio failure stress of concrete limited by(D/t)is obtained and discussed with empirical relationship.Polypropylene fibers were found to slightly increase column strength up to a certain volume fraction,after which the strength generally experienced a decrease.
基金Supported by the Industrial Foundation(20091041038)
文摘The flow process of unplasticized polyvinyl chloride （U PVC） through the mixing zone of intermeshing counter rotating and co rotating twin screw extruders （TSEs） were numerically simula ted by the finite element method. Three dimensional isothermal flow field of U-PVC in two kinds of TSE was calculated. The mixing performance of the screw elements of the extruders was statistically analyzed by particle tracking method. The dispersive mixing performance was characterized by the mixing index, the logarithm of stretching, and the segregation scale. The distributive mixing per forulance was characterized by the resident time distribution. The results indicate that the counter rotating TSE can build higher pressure and generate higher axial velocity and shear rate, whereas the co rotating TSE has better performance in dispersive and distributive mixing.
