Optimal Design Of Semi-rigid Steel Frame Structure Considering Failure Mode Control

With the development of technology,the society has put forward higher requirements for the design of steel structures.How to quickly obtain a more economical and reasonable structural design has become the focus of steel structure design research.The structural optimization using intelligent optimization algorithm can overcome the defects of traditional optimization methods,such as repeated checking and relying on the experience of designers,and make the structural design process automatic,thus saving manpower,material resources and time.At the same time,structural optimization is a process of rational allocation of limited resources and an important measure to protect the natural environment and promote green social development.Therefore,the structural optimization design of steel structure is a very important research topic.This paper mainly studies the optimal design of steel frame considering failure mode control and the influence of semi-rigid joints,including the following work:1)The information database of beam-column semi-rigid connection joints which can meet the requirements of structural optimization and failure mode control is designed and established.2)The internal force analysis method of semi-rigid connected steel frame is studied,and the element stiffness matrix in local coordinate system considering semi-rigid joints is derived,and the internal force analysis program is compiled.3)the failure mode of steel frame structure and the failure mode control method are studied.the control constraints of failure modes of steel frame structures considering semi-rigid joints is derived.The design process and mathematical model of two-phase structure optimization design is given,and the structural optimization is realized by using the genetic algorithm with the elitist strategy,Combined with the joint information base and the internal force analysis of the semi-rigid steel frame.On this basis,three structural optimization design examples and Pushover analysis are used to verify the effectiveness of the proposed optimization design and failure mode control.Through the above work and research,the following important conclusions are drawn:1)The semi-rigid joint information database established in this paper can provide the actual structure corresponding to the joint stiffness and bending moment yield capacity,and make the optimized structure have a better failure mode than the structure without the joint information database.2)The genetic algorithm with elitist strategy can quickly and stably converge to the global optimal solution in the optimal design of semi-rigid steel frame structures;The optimization process is divided into two phase to make the optimization algorithm more suitable for failure mode control,which can effectively solve the problems that the beam design does not consider transverse load and the component design does not consider stiffness and stability requirements in the original failure mode control design method.3)the optimal design scheme of semi-rigid steel frame structural optimization design with the failure mode control can form the failure mode of beam end semi-rigid connection plastic hinge as the main energy dissipation member,which ensures the design requirements of the structure in the elastic working state,and greatly improves the ductility and the overall energy dissipation capacity of the structure.