Documents disponibles écrits par cet auteur

Effect of longitudinal stress gradients on elastic buckling of thin plates / Yu Cheng in Journal of engineering mechanics, Vol. 133 N°4 (Avril 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.452–463. Titre : Effect of longitudinal stress gradients on elastic buckling of thin plates Type de document : texte imprimé Auteurs : Yu Cheng, Auteur ; Benjamin W. Schafer, Auteur Année de publication : 2007 Article en page(s) : pp.452–463. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Buckling  Stability  Thin  wall  structures  Elasticity  Cold-formed  steel  Plates Résumé : This paper analyzes the effect of longitudinal stress gradients on the elastic buckling of thin isotropic plates. Two types of thin plates are considered: (1) a plate simply supported on all four edges and rotationally restrained on two longitudinal edges; and (2) a plate simply supported on three edges with one longitudinal edge free and the opposite longitudinal edge rotationally restrained. These two cases illustrate the influence of longitudinal stress gradient on stiffened and unstiffened elements, respectively. A semianalytical method is derived and presented herein to calculate the elastic-buckling stress of both types of rectangular thin plates subjected to nonuniform applied longitudinal stresses. Finite-element analysis using ABAQUS is employed to validate the semianalytical model for plates with fixed and/or simple supports. Empirical formulas are produced to calculate the buckling coefficients of plates with fixed and/or simple supports under longitudinal stress gradients. The results help establish a better understanding of the effect of longitudinal stress gradients on the elastic buckling of thin plates and are intended to aid in the development of design provisions to include these effects in the strength prediction of thin-walled beams under moment gradients. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2845 [...] [article] Effect of longitudinal stress gradients on elastic buckling of thin plates [texte imprimé] / Yu Cheng, Auteur ; Benjamin W. Schafer, Auteur . - 2007 . - pp.452–463. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°4 (Avril 2007) . - pp.452–463. Mots-clés : Buckling  Stability  Thin  wall  structures  Elasticity  Cold-formed  steel  Plates Résumé : This paper analyzes the effect of longitudinal stress gradients on the elastic buckling of thin isotropic plates. Two types of thin plates are considered: (1) a plate simply supported on all four edges and rotationally restrained on two longitudinal edges; and (2) a plate simply supported on three edges with one longitudinal edge free and the opposite longitudinal edge rotationally restrained. These two cases illustrate the influence of longitudinal stress gradient on stiffened and unstiffened elements, respectively. A semianalytical method is derived and presented herein to calculate the elastic-buckling stress of both types of rectangular thin plates subjected to nonuniform applied longitudinal stresses. Finite-element analysis using ABAQUS is employed to validate the semianalytical model for plates with fixed and/or simple supports. Empirical formulas are produced to calculate the buckling coefficients of plates with fixed and/or simple supports under longitudinal stress gradients. The results help establish a better understanding of the effect of longitudinal stress gradients on the elastic buckling of thin plates and are intended to aid in the development of design provisions to include these effects in the strength prediction of thin-walled beams under moment gradients. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A4%2845 [...]

Reaction mechanism of coal chemical looping process for syngas production with CaSO4 oxygen carrier in the CO2 atmosphere / Yongzhuo Liu in Industrial & engineering chemistry research, Vol.51 N° 31 (Août 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10364-10373 Titre : Reaction mechanism of coal chemical looping process for syngas production with CaSO4 oxygen carrier in the CO2 atmosphere Type de document : texte imprimé Auteurs : Yongzhuo Liu, Auteur ; Qingjie Guo, Auteur ; Yu Cheng, Auteur Année de publication : 2012 Article en page(s) : pp. 10364-10373 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Production  Synthesis  gas  Coal  Reaction  mechanism Résumé : Chemical looping combustion process for gaseous and solid fuel has been investigated widely. Recently, particular attention is paid to syngas and hydrogen generation from natural gas or solid fuels. CaSO4 has been proved to be a promising oxygen carrier for the chemical looping process with the merit of low price and environmental friendliness. The reaction mechanism of coal and pure CaSO4 for syngas production in the CO2 atmosphere was investigated using the simultaneous thermal analyzer in this paper. First, the thermodynamic analysis of reaction between coal and CaSO4 with different mass ratios was carried out respectively in N2 and CO2 atmospheres. It predicted that the CO2 can promote the reactions, while the coal-CaSO4 mass ratios affected the fate of sulfurous gaseous species greatly. Subsequently, thermogravimetric experiments were conducted by the peak fitting technique. It concluded that the drying and pyrolysis of the coal were main reactions before 800 °C, while the complex reactions, including the reaction between CaSO4 and coal char, gasification of coal char, and the decomposition of CaSO4, occurred during 800―1100 °C. The reaction kinetics and types of the reaction between coal and CaSO4 for syngas in the CO2 atmosphere were explored by isoconversional method. It indicated that the complex processes were controlled by the diffusion of gas—solid or solid―solid first, followed by parallel competing reactions. Finally, the reaction residues between coal and pure CaSO4 with different mole ratios were analyzed using scanning electron microscopy and energy dispersive spectrometer (SEM-EDS). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26234067 [article] Reaction mechanism of coal chemical looping process for syngas production with CaSO4 oxygen carrier in the CO2 atmosphere [texte imprimé] / Yongzhuo Liu, Auteur ; Qingjie Guo, Auteur ; Yu Cheng, Auteur . - 2012 . - pp. 10364-10373. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol.51 N° 31 (Août 2012) . - pp. 10364-10373 Mots-clés : Carbon  dioxide  Production  Synthesis  gas  Coal  Reaction  mechanism Résumé : Chemical looping combustion process for gaseous and solid fuel has been investigated widely. Recently, particular attention is paid to syngas and hydrogen generation from natural gas or solid fuels. CaSO4 has been proved to be a promising oxygen carrier for the chemical looping process with the merit of low price and environmental friendliness. The reaction mechanism of coal and pure CaSO4 for syngas production in the CO2 atmosphere was investigated using the simultaneous thermal analyzer in this paper. First, the thermodynamic analysis of reaction between coal and CaSO4 with different mass ratios was carried out respectively in N2 and CO2 atmospheres. It predicted that the CO2 can promote the reactions, while the coal-CaSO4 mass ratios affected the fate of sulfurous gaseous species greatly. Subsequently, thermogravimetric experiments were conducted by the peak fitting technique. It concluded that the drying and pyrolysis of the coal were main reactions before 800 °C, while the complex reactions, including the reaction between CaSO4 and coal char, gasification of coal char, and the decomposition of CaSO4, occurred during 800―1100 °C. The reaction kinetics and types of the reaction between coal and CaSO4 for syngas in the CO2 atmosphere were explored by isoconversional method. It indicated that the complex processes were controlled by the diffusion of gas—solid or solid―solid first, followed by parallel competing reactions. Finally, the reaction residues between coal and pure CaSO4 with different mole ratios were analyzed using scanning electron microscopy and energy dispersive spectrometer (SEM-EDS). ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26234067