Height limitations are not uncommon in multi-storey buildings due to economic requirements and esthetical considerations. Substantial spaces are normally required to enable the passage of large pipes and ducts beneath...Height limitations are not uncommon in multi-storey buildings due to economic requirements and esthetical considerations. Substantial spaces are normally required to enable the passage of large pipes and ducts beneath steel beams leading to uneconomic floor heights. The most adopted solution for this issue is the use of steel beam web openings to provide the required space for services. These openings could lead to a significant decrease of the beam load carrying capacity depending on the adopted openings shape, size and location. These aspects motivated the present study based on FE simulations calibrated against numerical and test results. The results accuracy enabled a comprehensive parametric analysis of beams with web openings to be made focused on the profile size, web opening location, among others. The study also investigated the efficiency of longitudinal stiffeners welded at the opening region and benefits of using an adequate edge concordance radius in beams with rectangular and square openings. The obtained results showed the need of using welded longitudinal stiffeners in order to increase the beams ultimate load carrying capacity. This adoption can double or even triple the ultimate load of beams with rectangular and square opening heights equal to 0.75 H, respectively.展开更多
The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and structures.Curved structure can support the external loads eff...The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and structures.Curved structure can support the external loads effectively by virtue of their spatial curvature.In review of the excellent energy absorption property of auxetic structure,employing auxetic structure as core material in curved sandwich shows the potential to improve the protection performance.In this study,a novel cylindrical sandwich panel with double arrow auxetic(DAA) core was designed and the numerical model was built by ABAQUS.Due to the complexity of the structure,systematic parameter study and optimal design are conducted.Two cases of optimal design were considered,case1 focuses on reducing the deflection and mass of the structure,while case2 focuses on reducing the deflection and increasing the energy absorption per unit mass.Parameter study and optimal design were conducted based on Latin Hypercube Sampling(LHD)method,artificial neural networks(ANN) metamodel and the nondominated sorting genetic algorithm(NSGA-Ⅱ).The Pareto front was obtained and the cylindrical DAA structure performed much better than its equal solid panel in both blast resistance and energy absorption capacity.Optimization results can be used as a reference for different applications.展开更多
A mathematical model of optimization for cargo hold structure of small and medium-sized duplex stainless steel (DSS) chemical tankers based on the rule is described.The weight of DSS is defined as the objective functi...A mathematical model of optimization for cargo hold structure of small and medium-sized duplex stainless steel (DSS) chemical tankers based on the rule is described.The weight of DSS is defined as the objective function.The explicit formulas of the relevant rules,the explicit geometric relations formed by the structural arrangement and the implicit constraints such as layout,lines,expert experience,workmanship and so on are taken as the constraints.The design variables and the algorithm are determined by analyzing the logical relations among the factors.Besides,the efficiency of the optimum algorithm is improved by utilizing the distribution law of the optimal corrugations.Finally,the comprehensive optimization of the cargo hold DSS is accomplished by C++ programming.The weight of the optimized scheme of the example is 4.93% lower than that of the original scheme.The finite element analysis results show that the optimized scheme is satisfied with the requirements of the rules and has a good structure performance.The optimization method based on the rules and accomplished by the programming is practical for structural preliminary design.展开更多
文摘Height limitations are not uncommon in multi-storey buildings due to economic requirements and esthetical considerations. Substantial spaces are normally required to enable the passage of large pipes and ducts beneath steel beams leading to uneconomic floor heights. The most adopted solution for this issue is the use of steel beam web openings to provide the required space for services. These openings could lead to a significant decrease of the beam load carrying capacity depending on the adopted openings shape, size and location. These aspects motivated the present study based on FE simulations calibrated against numerical and test results. The results accuracy enabled a comprehensive parametric analysis of beams with web openings to be made focused on the profile size, web opening location, among others. The study also investigated the efficiency of longitudinal stiffeners welded at the opening region and benefits of using an adequate edge concordance radius in beams with rectangular and square openings. The obtained results showed the need of using welded longitudinal stiffeners in order to increase the beams ultimate load carrying capacity. This adoption can double or even triple the ultimate load of beams with rectangular and square opening heights equal to 0.75 H, respectively.
文摘The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and structures.Curved structure can support the external loads effectively by virtue of their spatial curvature.In review of the excellent energy absorption property of auxetic structure,employing auxetic structure as core material in curved sandwich shows the potential to improve the protection performance.In this study,a novel cylindrical sandwich panel with double arrow auxetic(DAA) core was designed and the numerical model was built by ABAQUS.Due to the complexity of the structure,systematic parameter study and optimal design are conducted.Two cases of optimal design were considered,case1 focuses on reducing the deflection and mass of the structure,while case2 focuses on reducing the deflection and increasing the energy absorption per unit mass.Parameter study and optimal design were conducted based on Latin Hypercube Sampling(LHD)method,artificial neural networks(ANN) metamodel and the nondominated sorting genetic algorithm(NSGA-Ⅱ).The Pareto front was obtained and the cylindrical DAA structure performed much better than its equal solid panel in both blast resistance and energy absorption capacity.Optimization results can be used as a reference for different applications.
文摘A mathematical model of optimization for cargo hold structure of small and medium-sized duplex stainless steel (DSS) chemical tankers based on the rule is described.The weight of DSS is defined as the objective function.The explicit formulas of the relevant rules,the explicit geometric relations formed by the structural arrangement and the implicit constraints such as layout,lines,expert experience,workmanship and so on are taken as the constraints.The design variables and the algorithm are determined by analyzing the logical relations among the factors.Besides,the efficiency of the optimum algorithm is improved by utilizing the distribution law of the optimal corrugations.Finally,the comprehensive optimization of the cargo hold DSS is accomplished by C++ programming.The weight of the optimized scheme of the example is 4.93% lower than that of the original scheme.The finite element analysis results show that the optimized scheme is satisfied with the requirements of the rules and has a good structure performance.The optimization method based on the rules and accomplished by the programming is practical for structural preliminary design.
