Documents disponibles écrits par cet auteur

Impact of stochastic traffic on modified cross - section profiles of a slender long - span bridge / Suren Chen in Journal of engineering mechanics, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 139 N° 3 (Mars 2013) . - pp.347–358. Titre : Impact of stochastic traffic on modified cross - section profiles of a slender long - span bridge : wind tunnel experimental investigation Type de document : texte imprimé Auteurs : Suren Chen, Auteur ; Ryan Nelson, Auteur ; Feng Chen, Auteur Année de publication : 2013 Article en page(s) : pp.347–358. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Long-span  bridge  Section  model  Flutter  derivatives  Wind  tunnel  Traffic Résumé : For a slender long-span bridge, the global aeroelastic and aerodynamic phenomena, such as flutter stability and buffeting response, induced by wind turbulence significantly affect the safety and lifetime performance of the bridge. To investigate these phenomena, a wind tunnel experimental technique with bridge section models is typically required to identify some critical aerodynamic coefficients, such as flutter derivatives, which are dependent on the specific profile (shape) of a bridge cross section and the functions of reduced frequencies. Obviously, this practice is based on the assumption that the shape of the cross section of a long-span bridge does not vary over time. Such an assumption may not remain valid when the stochastic traffic on the bridge is considered, because of the simple fact that the presence of vehicles changes the profile of the bridge cross section. The current study aims to provide some insights through experimental assessment of traffic impacts on flutter derivatives of the modified bridge cross section because of the presence of traffic. A bridge section model with scaled vehicle models distributed on the bridge deck is tested in the wind tunnel following the simulated stochastic traffic flow. Several scenarios are tested to provide insights on the variations of the flutter derivatives over different sections along the bridge and at different time instants for the same location. In addition, some extreme situations, such as under evacuation or serious congestion, are also studied. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000444 [article] Impact of stochastic traffic on modified cross - section profiles of a slender long - span bridge : wind tunnel experimental investigation [texte imprimé] / Suren Chen, Auteur ; Ryan Nelson, Auteur ; Feng Chen, Auteur . - 2013 . - pp.347–358. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 139 N° 3 (Mars 2013) . - pp.347–358. Mots-clés : Long-span  bridge  Section  model  Flutter  derivatives  Wind  tunnel  Traffic Résumé : For a slender long-span bridge, the global aeroelastic and aerodynamic phenomena, such as flutter stability and buffeting response, induced by wind turbulence significantly affect the safety and lifetime performance of the bridge. To investigate these phenomena, a wind tunnel experimental technique with bridge section models is typically required to identify some critical aerodynamic coefficients, such as flutter derivatives, which are dependent on the specific profile (shape) of a bridge cross section and the functions of reduced frequencies. Obviously, this practice is based on the assumption that the shape of the cross section of a long-span bridge does not vary over time. Such an assumption may not remain valid when the stochastic traffic on the bridge is considered, because of the simple fact that the presence of vehicles changes the profile of the bridge cross section. The current study aims to provide some insights through experimental assessment of traffic impacts on flutter derivatives of the modified bridge cross section because of the presence of traffic. A bridge section model with scaled vehicle models distributed on the bridge deck is tested in the wind tunnel following the simulated stochastic traffic flow. Several scenarios are tested to provide insights on the variations of the flutter derivatives over different sections along the bridge and at different time instants for the same location. In addition, some extreme situations, such as under evacuation or serious congestion, are also studied. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000444

Performance enhancement of poly(lactic acid) and sugar beet pulp composites by improving interfacial adhesion and penetration / Feng Chen ; LinShu Liu ; Peter H. Cooke ; Kevin B. Hicks in Industrial & engineering chemistry research, Vol. 47 n°22 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8667–8675 Titre : Performance enhancement of poly(lactic acid) and sugar beet pulp composites by improving interfacial adhesion and penetration Type de document : texte imprimé Auteurs : Feng Chen, Auteur ; LinShu Liu, Auteur ; Peter H. Cooke, Auteur ; Kevin B. Hicks, Auteur Année de publication : 2008 Article en page(s) : p. 8667–8675 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Poly(lactic  acid) Résumé : Sugar beet pulp (SBP), the residue from the sugar extraction process, contains abundant dietary fibers and is mainly used for feedstuff. In this study, poly(lactic acid) (PLA) and SBP composites were prepared using a twin screw extruder. The phase structure, thermal properties, mechanical properties, and water absorption of the composites were studied. The molecular weight change of PLA in the composites was also studied. Polymeric diphenylmethane diisocyanate (pMDI) was used as a coupling agent and resulted in significant increases in mechanical properties and water resistance. The tensile strength of the PLA/SBP (70/30 w/w) composite was only 56.9% that of neat PLA, but it was increased to 80.3% with the addition of 0.5% pMDI and further increased to 93.8% at 2% pMDI. With 50% SBP and 2% pMDI, the tensile strength of the composite was 87.8% of that of neat PLA. The microstructure of the composites indicated that the addition of pMDI greatly improved the wettability of the SBP particles by PLA and increased the penetration of PLA into the porous SBP. Consequently, the failure of the composites in mechanical testing changed from extensive debonding without pMDI to progressive rupture of the SBP particles with pMDI. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800930j [article] Performance enhancement of poly(lactic acid) and sugar beet pulp composites by improving interfacial adhesion and penetration [texte imprimé] / Feng Chen, Auteur ; LinShu Liu, Auteur ; Peter H. Cooke, Auteur ; Kevin B. Hicks, Auteur . - 2008 . - p. 8667–8675. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8667–8675 Mots-clés : Poly(lactic  acid) Résumé : Sugar beet pulp (SBP), the residue from the sugar extraction process, contains abundant dietary fibers and is mainly used for feedstuff. In this study, poly(lactic acid) (PLA) and SBP composites were prepared using a twin screw extruder. The phase structure, thermal properties, mechanical properties, and water absorption of the composites were studied. The molecular weight change of PLA in the composites was also studied. Polymeric diphenylmethane diisocyanate (pMDI) was used as a coupling agent and resulted in significant increases in mechanical properties and water resistance. The tensile strength of the PLA/SBP (70/30 w/w) composite was only 56.9% that of neat PLA, but it was increased to 80.3% with the addition of 0.5% pMDI and further increased to 93.8% at 2% pMDI. With 50% SBP and 2% pMDI, the tensile strength of the composite was 87.8% of that of neat PLA. The microstructure of the composites indicated that the addition of pMDI greatly improved the wettability of the SBP particles by PLA and increased the penetration of PLA into the porous SBP. Consequently, the failure of the composites in mechanical testing changed from extensive debonding without pMDI to progressive rupture of the SBP particles with pMDI. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800930j

Reinforcing and toughening effects of bamboo pulp fiber on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber composites / Jiang, Long in Industrial & engineering chemistry research, Vol. 49 N° 2 (Janvier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 572–577 Titre : Reinforcing and toughening effects of bamboo pulp fiber on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber composites Type de document : texte imprimé Auteurs : Jiang, Long, Auteur ; Feng Chen, Auteur ; Qian, Jun, Auteur Année de publication : 2010 Article en page(s) : pp 572–577 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Fiber  Composites  Hydroxybutyrate  Hydroxyvalerate. Résumé : In this work, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber composites were melt-compounded and injection-molded. Tensile, impact and dynamic mechanical properties of the composites were studied. In contrast to many other short natural fiber reinforced biocomposites which demonstrate decreased strain-at-break, impact toughness and tensile strength, the PHBV/bamboo pulp fiber composites displayed increased tensile strength and impact toughness, and maintained/increased strain-at-break. Microscopic study of the fracture surfaces revealed extensive fiber pullout in both tensile and impact tests. The fiber pullout suggests insufficient interfacial adhesion between the fiber and the matrix. The pullout process in the impact testing dissipated a significant amount of energy and hence substantially improved the impact toughness of the composites. With the improved interfacial adhesion provided by coupling agent polymeric diphenylmethane diisocyanate (pMDI), the strength and modulus of the composites were further increased. However, the toughness was decreased due to the inhibition of the fiber pullout. An acoustic emission test revealed a significantly different process of structural change for the composites with/without pMDI during tension test. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900953z [article] Reinforcing and toughening effects of bamboo pulp fiber on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber composites [texte imprimé] / Jiang, Long, Auteur ; Feng Chen, Auteur ; Qian, Jun, Auteur . - 2010 . - pp 572–577. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 2 (Janvier 2010) . - pp 572–577 Mots-clés : Fiber  Composites  Hydroxybutyrate  Hydroxyvalerate. Résumé : In this work, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber composites were melt-compounded and injection-molded. Tensile, impact and dynamic mechanical properties of the composites were studied. In contrast to many other short natural fiber reinforced biocomposites which demonstrate decreased strain-at-break, impact toughness and tensile strength, the PHBV/bamboo pulp fiber composites displayed increased tensile strength and impact toughness, and maintained/increased strain-at-break. Microscopic study of the fracture surfaces revealed extensive fiber pullout in both tensile and impact tests. The fiber pullout suggests insufficient interfacial adhesion between the fiber and the matrix. The pullout process in the impact testing dissipated a significant amount of energy and hence substantially improved the impact toughness of the composites. With the improved interfacial adhesion provided by coupling agent polymeric diphenylmethane diisocyanate (pMDI), the strength and modulus of the composites were further increased. However, the toughness was decreased due to the inhibition of the fiber pullout. An acoustic emission test revealed a significantly different process of structural change for the composites with/without pMDI during tension test. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900953z