Optimization Of The Composite Space Truss Based On The Overall Ultimate Bearing Capacity

Composite space truss structure composed of reinforced concrete slab and steel truss combination, because of its novel structure form, ingenious structure layout, reasonable arrangement of the materials, and widely used in modern engineering, developed rapidly in recent decades.But now the research for composite space truss structures is mainly focused on the elastic stage, and lack of profound understanding of the structure into plastic, achieve the ultimate bearing capacity until structural failure in the whole loading process.And the optimization design of composite space truss is also based on the overall structure of the linear elastic analysis, with the bearing capacity of a single component as constraint condition, pursuit as much as possible of the full stress design of single component, this optimization method maybe form weak links in important mechanical parts of the overall structure, and also failed to consider the surplus bearing capacity of the overall structure after the plastic internal force redistribution, this is clearly unreasonable.For tracing the ultimate bearing capacity of composite space truss, designed of large scale composite space truss analysis model according to standards, and established numerical model by using the finite element program Ansys, simulated the whole stress process of structure from the initial load to achieve the ultimate state, found out the the failure mode and the ultimate bearing capacity of the structure by tracing the damage development process.Analyzed and compared the existing optimization examples, the results showed that, without considering the ultimate bearing capacity in the optimization constraints, the ultimate bearing capacity of the final optimization results were randomly increase or decrease, the overall ultimate bearing state safety of structure was not uniform.Established parametric optimization model of composite space truss as a condition of the overall ultimate bearing capacity based on Ansys, selected part of the variables did the optimization analysis based on the size, preliminary results showed that, the optimization effect was obvious.