To study the static bending creep properties of glass fiber reinforced wood,glass fiber reinforced poplar(GFRP)specimens were obtained by pasting glass fiber on the upper and lower surfaces of Poplar(Populus euramevic...To study the static bending creep properties of glass fiber reinforced wood,glass fiber reinforced poplar(GFRP)specimens were obtained by pasting glass fiber on the upper and lower surfaces of Poplar(Populus euramevicana,P),the performance of Normal Creep(NC)and Mechanical Sorptive Creep(MSC)of GFRP and their influencing factors were tested and analyzed.The test results and analysis show that:(1)The MOE and MOR of Poplar were increased by 17.06%and 10.00%respectively by the glass fiber surface reinforced composite.(2)The surface reinforced P with glass fiber cloth only exhibits the NC pattern of wood and loses the MSC characteristics of wood,regardless of the constant or alternating changes in relative humidity.(3)The instantaneous elastic deformation,viscoelastic deformation,viscous deformation and total creep deflection of GFRP are positively correlated with the stress level of the external load applied to the specimen.Still,the specimen’s creep recovery rate is negatively correlated with the stress level of the external load applied to the specimen.The static creep deflection and viscous deformation of GFRP increase with the increase of the relative humidity of the environment.(4)The MSC maximum creep deflection of GFRP increased by only 7.41%over the NC maximum creep deflection,but the MSC maximum creep deflection of P increased by 199.25%over the NC maximum creep deflection.(5)The Burgers 4-factor model and the Weibull distribution equation can fit the NC and NC recovery processes of GFRP well.展开更多
During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees o...During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees of property damage and casualties to the construction of the tunnel,seriously affecting harmony during construction.The domestic emergency hedging is mainly the use of 8-10mm steel coils,but the steel is heavy and not suitable for the frequent movement of tunnels.This paper introduces the new Glass Fiber Reinforced Polymer Composite(GFRPC)escape pipeline used in Chongqing Jiuyongyi Jinyunshan Tunnel,and compares the traditional steel coil parameters to provide reference for subsequent tunnel hedging measures.展开更多
利用双螺杆挤出机熔融共混的方法制备了不同含量的碳纤维(CF)与尼龙共聚物(PA6T/66)复合材料,通过差示扫描量热仪、热重分析仪、扫描电子显微镜和力学性能测试研究了该复合材料的热性能、力学性能和断面形态结构。结果显示,复合材料的...利用双螺杆挤出机熔融共混的方法制备了不同含量的碳纤维(CF)与尼龙共聚物(PA6T/66)复合材料,通过差示扫描量热仪、热重分析仪、扫描电子显微镜和力学性能测试研究了该复合材料的热性能、力学性能和断面形态结构。结果显示,复合材料的起始分解温度均在400℃以上,熔点都在300℃左右。随着CF含量的增加,复合材料的拉伸强度、弯曲强度和冲击强度都相应增加,当CF质量分数达到40%时,复合材料的拉伸强度、弯曲强度和冲击强度分别达到最大值:226.1 MPa、354.7 MPa、54.1 k J/m2。展开更多
基金The present work was financially sponsored by the National Natural Science Foundation of China(Grant No.31960291).
文摘To study the static bending creep properties of glass fiber reinforced wood,glass fiber reinforced poplar(GFRP)specimens were obtained by pasting glass fiber on the upper and lower surfaces of Poplar(Populus euramevicana,P),the performance of Normal Creep(NC)and Mechanical Sorptive Creep(MSC)of GFRP and their influencing factors were tested and analyzed.The test results and analysis show that:(1)The MOE and MOR of Poplar were increased by 17.06%and 10.00%respectively by the glass fiber surface reinforced composite.(2)The surface reinforced P with glass fiber cloth only exhibits the NC pattern of wood and loses the MSC characteristics of wood,regardless of the constant or alternating changes in relative humidity.(3)The instantaneous elastic deformation,viscoelastic deformation,viscous deformation and total creep deflection of GFRP are positively correlated with the stress level of the external load applied to the specimen.Still,the specimen’s creep recovery rate is negatively correlated with the stress level of the external load applied to the specimen.The static creep deflection and viscous deformation of GFRP increase with the increase of the relative humidity of the environment.(4)The MSC maximum creep deflection of GFRP increased by only 7.41%over the NC maximum creep deflection,but the MSC maximum creep deflection of P increased by 199.25%over the NC maximum creep deflection.(5)The Burgers 4-factor model and the Weibull distribution equation can fit the NC and NC recovery processes of GFRP well.
文摘During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees of property damage and casualties to the construction of the tunnel,seriously affecting harmony during construction.The domestic emergency hedging is mainly the use of 8-10mm steel coils,but the steel is heavy and not suitable for the frequent movement of tunnels.This paper introduces the new Glass Fiber Reinforced Polymer Composite(GFRPC)escape pipeline used in Chongqing Jiuyongyi Jinyunshan Tunnel,and compares the traditional steel coil parameters to provide reference for subsequent tunnel hedging measures.
文摘利用双螺杆挤出机熔融共混的方法制备了不同含量的碳纤维(CF)与尼龙共聚物(PA6T/66)复合材料,通过差示扫描量热仪、热重分析仪、扫描电子显微镜和力学性能测试研究了该复合材料的热性能、力学性能和断面形态结构。结果显示,复合材料的起始分解温度均在400℃以上,熔点都在300℃左右。随着CF含量的增加,复合材料的拉伸强度、弯曲强度和冲击强度都相应增加,当CF质量分数达到40%时,复合材料的拉伸强度、弯曲强度和冲击强度分别达到最大值:226.1 MPa、354.7 MPa、54.1 k J/m2。
