Computation Technology Of Winding Flow Field And The Analysis Of Wind Pressure On Surface With Five Arch Folded Space Truss Structures

The five arch folding space truss structure processing the advantages of light self-weigh,big use-space,easy to transport and so on,is a foldable self-locking structure and widely used in the field of military engineering and civil engineering.Its light self-weigh and big use-space make it a typical wind-sensitive structure,and the wind load becomes the main factor to control its structural safety.At present,the research on wind load calculation of this kind of structure is still at the initial stage at home and abroad,and there is no wind load shape factor of this kind of structure in Chinese current load specifications.In this paper,a large eddy simulation method is used to study flow around bluff body of the five arch folding space truss structure,and the results of having practical engineering value are obtained.The main works and contributions of this thesis are listed as follows:According to the characteristics of structural wind engineering,this paper has developed a set of large eddy flow around bluff body simulation program,which can completely actualize grid partition and large eddy flow around bluff-body calculation.It accurately reflects the real flow field through setting reasonable boundary conditions,so it has good adaptability to complex boundaries.Utilizing the program proposed in this paper to simulate large eddy flow around bluff body of typical square column model and TTU building model and comparing the results with the documentary and experimental results,it shows that the program presented in this paper has high accuracy and can accurately reflect the characteristics of the flow field.Therefore,it is feasible in the study of flow mechanism.Secondly,numerical wind-tunnel simulation of five arch folded truss structure iscarried out by using the calculation program calculation put forward in this paper,moreover,calculates and analyzes the flow field distribution and mean wind pressure on the structure surface in the case of wind angle at 0 degrees and wind angle of 90 degrees.On the basis of this,some suggestions on the structural design are given.The experimental results show that the maximum negative pressure of the structure under the wind angle of 90 degrees is-550 pa,and the maximum negative pressure on the structure in the case of the wind direction of 0 degrees is only-320 pa.Under the two wind directions,the maximum positive pressure of the structure appears on the windward side,while the maximum negative value appears at the upper edge of the windward slope.In addition to the windward side,the maximum positive pressure or negative pressure of other side present at the corner or edge,so the face of each corner and edge should be seriously taken in considered when designing the structure.Finally,On the basis of the calculation results of the flow field distribution and mean wind pressure on the structure surface,this paper makes further efforts to calculate the wind load shape coefficient of the five arch folded truss structure.Comparing the correlation coefficient in Chinese load specification with the results this paper calculated,the result shows that the shape factor of wind load in windward side hardly differ with each other,which is 0.8.While in the windward slope,due to the influence of the angle area and the top surface,there is a big gap between this paper’s result and shape coefficient of similar structure’s windward slope offered by Chinese Standard.The results obtained in this paper provide a reference for the further optimization design of the structure,and provide data support for the next step.