Finite element analysis of mechanical behavior of concrete-filled square steel tube short columns with inner I-shaped CFRP profiles subjected to bi-axial eccentric load

[EN] The concrete-filed square steel tube with inner I-shaped CFRP profiles short columns under bi-axial eccentric load were investigated by the finite element analysis software ABAQUS. The working mechanism of the composite columns which is under bi-axial eccentric load are investigated by using the stress distribution diagram of steel tube concrete and the I-shaped CFRP profiles. In this paper, the main parameters; eccentric ratio, steel ratio, steel yield strength, concrete compressive strength and CFRP distribution rate of the specimens were investigated to know the mechanical behavior of them. The interaction between the steel tube and the concrete interface at different characteristic points of the composite columns were analyzed. The results showed that the ultimate bearing capacity of the concrete-filed square steel tube with inner I-shaped CFRP profiles short columns under bi-axial eccentric load decrease with the increase of eccentric ratio, the ultimate bearing capacity of the composite columns increase with the increase of steel ratio, steel yield strength, concrete compressive strength and CFRP distribution rate. The contact pressure between the steel tube and the concrete decreased from the corner zone to the flat zone, and the contact pressure decreased from the mid-height cross section to other sections.Li, G.; Zhan, Z.; Yang, Z.; Yang, Y. (2018). Finite element analysis of mechanical behavior of concrete-filled square steel tube short columns with inner I-shaped CFRP profiles subjected to bi-axial eccentric load. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 259-266. https://doi.org/10.4995/ASCCS2018.2018.6996OCS25926

Cooperative work behavior of high strength concrete-filled square high strength tubular stub columns with inner I-shaped CFRP under axial compression

[EN] The finite element software ABAQUS was used to analyze 22 high strength concrete-filled square high strength tubular short columns with inner I-shaped CFRP, all analysis results based on the finite element analysis data, six characteristic points were defined in the load-longitudinal strain curve of composite columns. The shared load of core concrete, square steel tube and inner I-shaped CFRP at different height sections of typical specimen corresponding to each characteristic point were analyzed and the cooperative work behavior of inner I-shaped CFRP, square steel tube and core concrete was analyzed. The results show that the existence of the inner I-shaped CFRP can effectively improve the ultimate bearing capacity composite columns, the middle region I-shaped CFRP sharing more longitudinal load than the end region CFRP and the shared load of concrete at the end region section is bigger than that of middle region section, before the CFRP brittle failure. The longitudinal load of square steel tube does not change with the change of the cross-section height.Li, G.; Yang, Y.; Yang, Z.; Zhan, Z. (2018). Cooperative work behavior of high strength concrete-filled square high strength tubular stub columns with inner I-shaped CFRP under axial compression. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 281-288. https://doi.org/10.4995/ASCCS2018.2018.6999OCS28128

Simulation and energetic assessment of the ammonia synthesis loop with ionic liquid-Based ammonia recovery from recycle gas

Ammonia (NH3) synthesis by Haber-Bosch process is recognized as the most important pathway for NH3 pro-duction. However, NH3 recovery from recycle gas using conventional condensation separation is still an energy-intensive process. Ionic liquids (ILs) have been proved to be effective solvents for NH3 separation and recovery due to their unique properties. In this work, a novel IL-based ammonia synthesis loop (IL-HB) was proposed, taking the protic IL [Bim][NTf2] as the absorbent to separate and recover NH3 from recycle gas, aiming to reduce the energy consumption and increase the NH3 production capacity of the synthesis tower. Then, a systematic methodology that considers reliable thermodynamic models as well as process simulation and assessment was established to evaluate the feasibility of the IL-HB. Furthermore, two entire processes (ILa-HB and ILb-HB) that integrate the optimal sections of IL-based NH3 recovery from recycle gas with the ammonia synthesis loop as a whole were simulated, taking the conventional Haber-Bosch ammonia synthesis loop (HB) as the benchmark. The simulation results prove great techno-economic potentials of the proposed ILa-HB and ILb-HB. Compared with the HB, the energy consumption and CO2 emissions of ILb-HB can be reduced by 16.01% and 29.44%, respec-tively, presenting enormous energy-saving and environment-friendly superiority

Simulation and energetic assessment of the ammonia synthesis loop with ionic liquid-Based ammonia recovery from recycle gas

Ammonia (NH3) synthesis by Haber-Bosch process is recognized as the most important pathway for NH3 pro-duction. However, NH3 recovery from recycle gas using conventional condensation separation is still an energy-intensive process. Ionic liquids (ILs) have been proved to be effective solvents for NH3 separation and recovery due to their unique properties. In this work, a novel IL-based ammonia synthesis loop (IL-HB) was proposed, taking the protic IL [Bim][NTf2] as the absorbent to separate and recover NH3 from recycle gas, aiming to reduce the energy consumption and increase the NH3 production capacity of the synthesis tower. Then, a systematic methodology that considers reliable thermodynamic models as well as process simulation and assessment was established to evaluate the feasibility of the IL-HB. Furthermore, two entire processes (ILa-HB and ILb-HB) that integrate the optimal sections of IL-based NH3 recovery from recycle gas with the ammonia synthesis loop as a whole were simulated, taking the conventional Haber-Bosch ammonia synthesis loop (HB) as the benchmark. The simulation results prove great techno-economic potentials of the proposed ILa-HB and ILb-HB. Compared with the HB, the energy consumption and CO2 emissions of ILb-HB can be reduced by 16.01% and 29.44%, respec-tively, presenting enormous energy-saving and environment-friendly superiority