In the present study,the mechanical properties of polyvinyl alcohol(PVA)-basalt hybrid fiber reinforced engineered cementitious composites(ECC)after exposure to elevated temperatures were experimentally investigated.F...In the present study,the mechanical properties of polyvinyl alcohol(PVA)-basalt hybrid fiber reinforced engineered cementitious composites(ECC)after exposure to elevated temperatures were experimentally investigated.Five temperatures of 20,50,100,200 and 400℃ were set to evaluate the residual compressive,tensile and flexural behaviors of hybrid and mono fiber ECC.It was shown that partial replacement of PVA fibers with basalt fibers endowed ECC with improved residual compressive toughness,compared to brittle failure of mono fiber ECC heated to 400℃.The tension tests indicated that the presence of basalt fibers benefited the tensile strength up to 200℃,and delayed the sharp reduction of strength to 400℃.Under flexural load,the peak deflections corresponding to flexural strengths of hybrid fiber ECC were found to be less vulnerable ranging from 20 to 100℃.Further,the scanning electron microscopy(SEM)results uncovered that the rupture of basalt fiber at moderate temperature and its pullout mechanism at high temperature was responsible for the mechanical evolution of hybrid fiber ECC.This work develops a better understanding of elevated temperature and basalt fiber impact on the residual mechanical properties and further provides guideline for tailoring ECC for improved fire resistance.展开更多
Due to notable characteristics,sustainability concept and environmental issues,hybridisation natural with synthetic fibres to fabricate composites have been rapidly gaining market share in different applications(struc...Due to notable characteristics,sustainability concept and environmental issues,hybridisation natural with synthetic fibres to fabricate composites have been rapidly gaining market share in different applications(structural,military,aerospace and automotive vehicles).Compression,tension and fatigue tests of various stacking sequences of plain jute/carbon reinforced(PVB)polyvinyl butyral by hot hydraulic press technique were experimentally conducted.Six types of fabricated composites with various constituents(jute,carbon and their hybrids)were fabricated and tested.Notably,fatigue lifetime of hybrids increases with increasing the carbon content relative to the jute fibre content.On the other hand,Jute composites possess high strain compared to pure carbon composite,which gives an overall improvement in mechanical behaviours.Interestingly,H1 hybrid with Carbon/Jute/Carbon sequences offers similar fatigue stiffness behaviour of H3 hybrid with Carbon/Jute/Carbon/Jute sequences when subjected to cyclic loading.Carbon composite(C)exhibited the highest fatigue resistance,whiles jute composite(J)possessed the highest strain and semi brittle trends in both mechanical and fatigue performance.Results concluded that plain jute fibres could partially replace high-cost synthetic carbon fibres to produce more eco-friendly hybrids to be utilised in different composites industries.展开更多
为解决反复开挖道路铺设多种管线造成交通拥堵且耗费大量建设成本的难题,提出侧壁出筋叠合板式拼装综合管廊,该管廊具有吊装方便、现场支模少、节点连接可靠、整体性和防水性好等优点。基于ABAQUS大型商用软件,建立水平荷载作用下侧壁...为解决反复开挖道路铺设多种管线造成交通拥堵且耗费大量建设成本的难题,提出侧壁出筋叠合板式拼装综合管廊,该管廊具有吊装方便、现场支模少、节点连接可靠、整体性和防水性好等优点。基于ABAQUS大型商用软件,建立水平荷载作用下侧壁出筋叠合板式拼装综合管廊有限元分析模型。为验证该模型的合理性,开展侧壁出筋叠合板式拼装综合管廊中节点试验,试验结果与有限元分析结果吻合良好。在此基础上,进一步开展叠合板式拼装综合管廊双舱整体结构足尺模型的有限元参数分析,分析参数包括腋角高度和轴压比。分析结果表明:1)双舱整体结构的破坏形态均为弯曲破坏。2)所有试件的峰值承载力在200.5~298.6 k N,层间位移角在1/43~1/27。3)相比于无腋角试件,当腋角高度分别为150 mm和250 mm时,有腋试件的峰值承载力分别提高24.4%和39.7%,峰值侧移分别增加49.3%和60.1%;当轴压比从0增加到0.05、0.10时,有腋试件的峰值承载力分别提升10.3%、19.7%,但峰值侧移分别降低5.2%、18.6%。总体上,侧壁出筋叠合板式拼装综合管廊双舱整体结构具有较大的承载力和较好的变形能力。展开更多
基金Project(51808545)supported by the National Natural Science Foundation of ChinaProject(8184083)supported by the Beijing Natural Science Foundation,ChinaProject(2021YQLJ05)supported by the Fundamental Research Funds for the Central Universities,China。
文摘In the present study,the mechanical properties of polyvinyl alcohol(PVA)-basalt hybrid fiber reinforced engineered cementitious composites(ECC)after exposure to elevated temperatures were experimentally investigated.Five temperatures of 20,50,100,200 and 400℃ were set to evaluate the residual compressive,tensile and flexural behaviors of hybrid and mono fiber ECC.It was shown that partial replacement of PVA fibers with basalt fibers endowed ECC with improved residual compressive toughness,compared to brittle failure of mono fiber ECC heated to 400℃.The tension tests indicated that the presence of basalt fibers benefited the tensile strength up to 200℃,and delayed the sharp reduction of strength to 400℃.Under flexural load,the peak deflections corresponding to flexural strengths of hybrid fiber ECC were found to be less vulnerable ranging from 20 to 100℃.Further,the scanning electron microscopy(SEM)results uncovered that the rupture of basalt fiber at moderate temperature and its pullout mechanism at high temperature was responsible for the mechanical evolution of hybrid fiber ECC.This work develops a better understanding of elevated temperature and basalt fiber impact on the residual mechanical properties and further provides guideline for tailoring ECC for improved fire resistance.
基金I would like to thank the Ministry of Higher Education&Scientific Research of Iraq and to Mustansiriyah University,College of Engineering,Mechanical Engineering Department,for the support for the work contained in this study in Iraq.
文摘Due to notable characteristics,sustainability concept and environmental issues,hybridisation natural with synthetic fibres to fabricate composites have been rapidly gaining market share in different applications(structural,military,aerospace and automotive vehicles).Compression,tension and fatigue tests of various stacking sequences of plain jute/carbon reinforced(PVB)polyvinyl butyral by hot hydraulic press technique were experimentally conducted.Six types of fabricated composites with various constituents(jute,carbon and their hybrids)were fabricated and tested.Notably,fatigue lifetime of hybrids increases with increasing the carbon content relative to the jute fibre content.On the other hand,Jute composites possess high strain compared to pure carbon composite,which gives an overall improvement in mechanical behaviours.Interestingly,H1 hybrid with Carbon/Jute/Carbon sequences offers similar fatigue stiffness behaviour of H3 hybrid with Carbon/Jute/Carbon/Jute sequences when subjected to cyclic loading.Carbon composite(C)exhibited the highest fatigue resistance,whiles jute composite(J)possessed the highest strain and semi brittle trends in both mechanical and fatigue performance.Results concluded that plain jute fibres could partially replace high-cost synthetic carbon fibres to produce more eco-friendly hybrids to be utilised in different composites industries.
文摘为解决反复开挖道路铺设多种管线造成交通拥堵且耗费大量建设成本的难题,提出侧壁出筋叠合板式拼装综合管廊,该管廊具有吊装方便、现场支模少、节点连接可靠、整体性和防水性好等优点。基于ABAQUS大型商用软件,建立水平荷载作用下侧壁出筋叠合板式拼装综合管廊有限元分析模型。为验证该模型的合理性,开展侧壁出筋叠合板式拼装综合管廊中节点试验,试验结果与有限元分析结果吻合良好。在此基础上,进一步开展叠合板式拼装综合管廊双舱整体结构足尺模型的有限元参数分析,分析参数包括腋角高度和轴压比。分析结果表明:1)双舱整体结构的破坏形态均为弯曲破坏。2)所有试件的峰值承载力在200.5~298.6 k N,层间位移角在1/43~1/27。3)相比于无腋角试件,当腋角高度分别为150 mm和250 mm时,有腋试件的峰值承载力分别提高24.4%和39.7%,峰值侧移分别增加49.3%和60.1%;当轴压比从0增加到0.05、0.10时,有腋试件的峰值承载力分别提升10.3%、19.7%,但峰值侧移分别降低5.2%、18.6%。总体上,侧壁出筋叠合板式拼装综合管廊双舱整体结构具有较大的承载力和较好的变形能力。
