Papers by Keyword: Flexural Property

Abstract: In this study, effect of Carbon Milled Fiber (CMF) addition on flexural fracture property of Carbon Fiber Reinforced Plastics (CFRP) was investigated. The CMF additive amounts to the epoxy resin were 0.5wt%, 0.8wt%, 1.0wt% and 1.2wt%. Static three point flexural test was conducted based on Japanese Industrial Standard (JIS) K 7074. The in situ observation of CMF added CFRP was conducted by using high-speed camera. As a result, following conclusions were obtained. In case that CMF additive amount was below 0.8wt%, flexural strength and flexural modulus of CFRP increased with an increase of CMF additive amount. In case of that CMF additive amount was above 1.0wt%, flexural strength and flexural modulus of the CFRP decreased compared with those of CMF 0.8wt% added CFRP. From in situ observation, crack initiation occurred at external layer on tension side of non CMF and CMF added CFRP. After crack initiation, delaminations of non CMF and CMF added CFRP were found. The delamination size of CMF 0.8wt% added CFRP was smaller than that of non CMF and CMF 1.2wt% added CFRP. Therefore, flexural property of CFRP was improved because delamination of CFRP was prevented by CMF 0.8wt%.

Abstract: This paper conducted an experiment to research flexural property of SMA unbounded prestressed box beam ,which applied the Shape Memory Alloy (SMA) at martensite state as externally prestressing tendons, and then through heating the SMA bars fully anchored on the beam with cracks by electrifying motivation, drove SMA to produce the “recovery stress” because of transformation, to study the effects of this stress on the deflection and crack width of concrete box-beam on work ,to study the recovery ability of SMA bars ,and to provide basis for the application of the SMA bars to bridge strengthening.

Abstract: In this study, effect of thermal cycling after water absorption on flexural property of CFRP(Carbon Fiber Reinforced Plastics) was examined. Water absorption tests were conducted for 24 hours, 100 hours and 500 hours at 90^°C. Thermal cycling test was conducted by using water absorbed specimen. The temperature range of thermal cycling test was from room temperature to-196^°C. The static three-point flexural test of CFRP with freezing after water absorption was conducted based on JIS(Japanese Industrial standard) K 7074. Following conclusions are obtained. In case of immersion for 24 hours, flexural strength and modulus of CFRP with freezing after water absorption decreased with an increase of the number of cycles. In case of immersion for 100 hours and 500 hours, flexural strength and modulus of CFRP with freezing after water absorption did not change. The water absorption of CFRP was the phenomenon that the water penetrated into fiber/resin interface. So, in the case of immersion for 24 hours that the absorption time is not so long, damage progresses gradually in thermal cycling test. On the other hand, in the case of immersion for 500 hours is long, the damage progresses at the early stage of the thermal cycling test, and after that the damage does not almost progress.

Abstract: Recent growth in the field of engineering demands specialised composite materials to meet various industrial needs. Composite materials are emerging as the most promising new materials. This paper deals with the fabrication and analysis of flexural characteristics of flax and Abaca hybrid epoxy composite. The show that GFRP + Flax +Abaca based hybrid composite has a higher ultimate stress which is much greater than GFRP + Flax composite and GFRP + Abaca composites. The inner filament breakage and crack propagation are studied using scanning electron microscope.

Abstract: A kind of novel antibacterial denture base powder incorporated with PMMA-modified nanoAg/NaZr₂(PO₄)₃ (CBD-300) was prepared by in-situ suspension polymerization and the flexural properties of denture base resin was investigated. CBD-300 was silanized by 3-methacryloxy propyl trimethoxyl silane (γ-MPS), and then γ-MPS-CBD-300 was grafted with poly (methyl methacrylate) (PMMA) to prepare M-CBD-300 which has a good compatibility with the denture base resin. Denture base powders with different addition of M-CBD-300 were prepared by in-situ suspension polymerization. Thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR) and water contact angle were used to characterize M-CBD-300. The size of denture base powder was observed by optical microscope. Universal testing apparatus and scanning electron microscope (SEM) were used to investigate flexural properties of denture base resin samples. The results showed that the surface of M-CBD-300 was successfully modified by PMMA, and the incorporation of M-CBD-300 leads to increasing of the denture base powder size. The flexural properties of the denture base resin samples prepared with our antibacterial denture base powders were enhanced greatly compared with the blank sample.

Abstract: In this study, the effects of water absorption and freezing on flexural property and mode I interlaminar fracture toughness of Carbon Fiber Reinforced Plastics (CFRP) were investigated. Plain woven carbon fiber was used as reinforcement. Epoxy resin was used as matrix. Water absorption test was conducted at 90°C for 24, 100, 250 and 500 hrs. After water absorption, the specimens were kept under-15°C for 24 hrs. Static three point flexural and Double Cantilever Beam (DCB) tests were conducted after water absorption and freezing. As a result, flexural strength and mode I interlaminar fracture toughness of CFRP after water absorption and freezing decreased with an increase of immersion time. Flexural modulus of CFRP did not change after water absorption and freezing. And flexural strength and mode I interlaminar fracture toughness of frozen CFRP after water absorption were lower than those of water absorbed CFRP. From the observation using scanning electron microscope, it is understood that the water absorption and freezing affects the interfacial adhesion between fiber and matrix.

Abstract: In order to study the effect of the fraction of PVA fiber on the axial compressive strength and flexural properties of high performance concrete, a series of tests have been conducted in this study. The middle span deflection was measured by a micrometer with dial indicator, and six different concrete mixes have been chosen. Flexural properties include flexural strength and flexural modulus of elasticity. The mechanism of PVA fiber acting on axial compressive strength, flexural strength and flexural modulus of elasticity has been analyzed in details. The results indicate that there is a tendency of increase in the axial compressive strength and flexural strength when the fiber volume fraction is below 0.08%, and the flexural modulus of elasticity of high-performance concrete decrease gradually with the increase of fiber volume fraction.

Abstract: In this study, effect of crystallinity on mechanical properties of carbon fiber reinforced thermoplastics (CFRTP) was investigated. Polypropylene (PP) and maleic anhydride modified polypropylene (MAPP) were used as matrix. The crystallinity of PP was controlled by using heat treatment after hot press molding of CFRTP. The range of crystallinity of PP and MAPP were from 26% to 40%. Flexural tests and izod impact tests of CFRTP were conducted based on Japanese Industrial Standard (JIS) K 7074 and JIS K 7110, respectively. As a result, flexural property and izod impact value of CFRTP using PP increased with an increase of crystallinity. However, flexural property and izod impact value of CFRTP using MAPP almost did not change with an increase of crystallinity.

Abstract: To study the effect of prestress level on beam for its flexural property, through comparing of the stress property of non-reinforced beam, non-prestressed fiber beam, and prestressed fiber beam. The experimental results show that non-prestressed fiber makes little difference in improving beams flexural property, while prestressed fiber has improved beams cracking load, yield load, bending rigidity greatly.

Abstract: The glass fiber reinforced polymer (GFRP) I-beams were tested under the third-point static loading. The load, mid-span deflection and failure modes were recorded during the flexural test. The flexural property was analyzed. The test results indicate that local buckling result in failure of integral structure. The local stability of flange plate is one of the main factors that affect the overall bending capacity of GFRP I-beams. Local strengthening should be adopted in the flange-web joint.