Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses ide...Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identifi cation and calibration of a suitable hysteretic model for GFRG wall panels fi lled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters(energy dissipation and pinching related parameters) were obtained for all fi ve test specimens.展开更多
The synthesis and characterization of a new class of cementitious composites filled with polymer emulsions were investigated, and their superior mechanical strength and durability properties compared to composites dev...The synthesis and characterization of a new class of cementitious composites filled with polymer emulsions were investigated, and their superior mechanical strength and durability properties compared to composites devoid of fi llers were reported. Polymer emulsions were utilized to mechanically reinforce the composite and bridge the cement, fly ash, aggregate and fibers. The results reveal that the epoxy emulsion and poly（ethylene-co-vinyl acetate） emulsion markedly enhance the mechanical and durability properties of cemetitious composites. The fi bers can be pulled out in the form of slip-hardening and the abrasion phenomenon can be observed clearly on the surface of the fibers. The hydration extent of cement is higher than that of the pristine composites. The polymer modified cementitious composites designed on micromechanics, have fl exibility and plasticity which could be applied for a novel form of multifunctional materials with a range of pipeline coatings applications.展开更多
The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were...The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were acquired using the brillouin optical time-domain reflectometer through the loading experiments of the composite beam structure. In addition, a finite element model of the composite beam structure was developed to analyze the mechanical responses of the epoxy asphalt mixture using the extended finite element method. The experimental results show that the development of crack propagation becomes instable with the increase of the load, and larger loads will generate deeper cracks. Moreover, the numerical results show that the mechanical response of the crack tip changes with the crack propagation, and the worst areas that subjected to crack damage are located on both sides of the composite beam structure.展开更多
Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic me...Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic mechanical and thermal properties are studied.The influence of ramie fiber and maleic anhydride-grafted polyolefin(MA-g-PO)on mechanical,dynamic mechanical and thermal properties is investigated.It is observed that the tensile,flexural and impact properties of the composites treated with MA-g-PO are all improved in comparison to the untreated composites.Dynamic mechanical properties of the composite with MA-g-PO show an increase in the storage modulus with a higherαrelaxation peak,together with the micromorphology analysis,indicating an improved interfacial bonding between fiber and matrix by the MA-g-PO addition.Furthermore,the change in TGA thermograms of composite caused by MA-g-PO exhibits that the addition of MA-g-PO is also helpful to increase the thermal stability of noil ramie fiber/HDPE composites.展开更多
The paper deals with the theoretic relationship betweenfineness of man-made fibers blended with natural fibersand regularities of the yarns made from them.Throughestablishment of the theory model and digitally analysi...The paper deals with the theoretic relationship betweenfineness of man-made fibers blended with natural fibersand regularities of the yarns made from them.Throughestablishment of the theory model and digitally analysisusing Matlab software,the optimum fineness of the fi-bers could be figured out.展开更多
Acoustic Emission Testing (AT) is one of the major non-destructive testing methods used for severity evaluation of structures. Amplitude distributions of AE signals are characterized by b-value and the value is mainly...Acoustic Emission Testing (AT) is one of the major non-destructive testing methods used for severity evaluation of structures. Amplitude distributions of AE signals are characterized by b-value and the value is mainly used for the severity evaluation of concrete structures until now. The value is assumed to be independent with propagation distance between acoustic emission sources to AE sensors. We evaluate the influence of the wide frequency band encountered in the fracture behavior of glass fiber reinforced plastic (GFRP) on the b-value analysis. In tensile tests, the b-value was determined from an acoustic emission (AE) source generated near a centered hole in a specimen of GFRP. At 15 mm from the hole, the b-value analysis indicated a decreasing trend with increasing tensile stress. At a propagation length of 45 mm, farthest from the hole, a?small number of AE signals were received. The attenuation is more rapid for high-frequency AE signals. Thus, the amplitude distribution bandwidth is wide and the b-value changes. This change in b-value for GFRPs is investigated by analyzing the spectral components of the AE signals. For a single-frequency AE source, the b-value is unchanged with propagation length. In contrast, multiple-frequency AE sources produce changes in b-value proportional to the fraction of each spectral component in the received signal. This is due to the frequency dependence of the attenuation with propagation length.?From these results, the b-value analysis cannot be applied to considering frequency dependence of AE attenuation.展开更多
文摘Glass fi ber reinforced gypsum(GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identifi cation and calibration of a suitable hysteretic model for GFRG wall panels fi lled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters(energy dissipation and pinching related parameters) were obtained for all fi ve test specimens.
基金Funded by the National Natural Science Foundation of China(No.21076227)
文摘The synthesis and characterization of a new class of cementitious composites filled with polymer emulsions were investigated, and their superior mechanical strength and durability properties compared to composites devoid of fi llers were reported. Polymer emulsions were utilized to mechanically reinforce the composite and bridge the cement, fly ash, aggregate and fibers. The results reveal that the epoxy emulsion and poly（ethylene-co-vinyl acetate） emulsion markedly enhance the mechanical and durability properties of cemetitious composites. The fi bers can be pulled out in the form of slip-hardening and the abrasion phenomenon can be observed clearly on the surface of the fibers. The hydration extent of cement is higher than that of the pristine composites. The polymer modified cementitious composites designed on micromechanics, have fl exibility and plasticity which could be applied for a novel form of multifunctional materials with a range of pipeline coatings applications.
基金Funded by the National Natural Science Foundation of China(No.51178114)the Fundamental Research Funds for the Central Universities(No.CXLX12_0117)the Scientifi c Research Foundation of Graduate School of Southeast University(No.YBJJ1318)
文摘The distributed optical fiber sensing technology was used to investigate the fracture behavior of the Epoxy Asphalt Mixture. The spatial distribution and variation of the strain development with crack propagation were acquired using the brillouin optical time-domain reflectometer through the loading experiments of the composite beam structure. In addition, a finite element model of the composite beam structure was developed to analyze the mechanical responses of the epoxy asphalt mixture using the extended finite element method. The experimental results show that the development of crack propagation becomes instable with the increase of the load, and larger loads will generate deeper cracks. Moreover, the numerical results show that the mechanical response of the crack tip changes with the crack propagation, and the worst areas that subjected to crack damage are located on both sides of the composite beam structure.
基金supported by the National Scientific and Technical Supporting 12th Five-year Plan Project(No.2012BAD23B0203)
文摘Noil discarded fibers from fiber production for textile industry have short length and are always considered less valuable.Here,noil ramie fibers/HDPE composite is prepared using twin-screw extruder and the dynamic mechanical and thermal properties are studied.The influence of ramie fiber and maleic anhydride-grafted polyolefin(MA-g-PO)on mechanical,dynamic mechanical and thermal properties is investigated.It is observed that the tensile,flexural and impact properties of the composites treated with MA-g-PO are all improved in comparison to the untreated composites.Dynamic mechanical properties of the composite with MA-g-PO show an increase in the storage modulus with a higherαrelaxation peak,together with the micromorphology analysis,indicating an improved interfacial bonding between fiber and matrix by the MA-g-PO addition.Furthermore,the change in TGA thermograms of composite caused by MA-g-PO exhibits that the addition of MA-g-PO is also helpful to increase the thermal stability of noil ramie fiber/HDPE composites.
文摘The paper deals with the theoretic relationship betweenfineness of man-made fibers blended with natural fibersand regularities of the yarns made from them.Throughestablishment of the theory model and digitally analysisusing Matlab software,the optimum fineness of the fi-bers could be figured out.
文摘Acoustic Emission Testing (AT) is one of the major non-destructive testing methods used for severity evaluation of structures. Amplitude distributions of AE signals are characterized by b-value and the value is mainly used for the severity evaluation of concrete structures until now. The value is assumed to be independent with propagation distance between acoustic emission sources to AE sensors. We evaluate the influence of the wide frequency band encountered in the fracture behavior of glass fiber reinforced plastic (GFRP) on the b-value analysis. In tensile tests, the b-value was determined from an acoustic emission (AE) source generated near a centered hole in a specimen of GFRP. At 15 mm from the hole, the b-value analysis indicated a decreasing trend with increasing tensile stress. At a propagation length of 45 mm, farthest from the hole, a?small number of AE signals were received. The attenuation is more rapid for high-frequency AE signals. Thus, the amplitude distribution bandwidth is wide and the b-value changes. This change in b-value for GFRPs is investigated by analyzing the spectral components of the AE signals. For a single-frequency AE source, the b-value is unchanged with propagation length. In contrast, multiple-frequency AE sources produce changes in b-value proportional to the fraction of each spectral component in the received signal. This is due to the frequency dependence of the attenuation with propagation length.?From these results, the b-value analysis cannot be applied to considering frequency dependence of AE attenuation.
