The Robust Optimization Research Of Purlin Bolt Arrangement Under Extreme Snow Load

Light steel structure is widely used in industrial and civil buildings for its high strength, light weight and a series of advantages. But because of the light steel structure itself overload ability is poor, meet with severe load prone to accidents, it is necessary to cause enough attention to study design personnel. In the composition of light steel structure without crane, the secondary purlin and wall components of beam steel quantity is very large, accounting for the total steel quantity about one third. So purlin is one of the key factors influencing the whole structure of economic and security. Comparing of the two kinds of connection form, continuous purlin and simply, purlin with continuous form can reduce the peak moment, reducing section purlin, save steel in the case of larger span purlin and load.Purlin’s continuity generally achieves through the use of nested lap and bolted.The working performance of continuous purlin is obtained by overlapping length cost components.In the process of connecting the bolt arrangement, including bolt logarithmic and bolt spacing changes will cause purlins lap length and stiffness of joints change, thereby affecting the purlins and even the carrying capacity of the entire structure.So reasonable purlin connection has very important significance to ensure the security of the overall design of the structure, reduce the amount of steel and control costs.I have a research and discussion about the bolt arrangement of continuous purline. First of all, I carry on a comprehensive analysis on the bearing capacity of purlin from three aspects, including when the same spacing affect the number of bolts on the bearing capacity of purlin, when the same impact on the number of bolt spacing purlin bearing capacity, the number and spacing of the bolts on the bearing capacity of purlin. Identified a roughly purlin lap length and more economic and reasonable and bearing capacity of the larger bolt arrangement,and then establish finite element model for the calculation of bearing capacity in the arrangement of bolt and the yield strength of material two variables as the standard. In addition, I also have an optimal experiment design of response surface inside of Design-Expert with the datas we have got from finite element analysis. The fitted response surface function corresponding response surface model. Through the analysis of variance for solving a significant factors to consider, to judge the degree of compliance with the response surface function fitting degree and the reality model.Better the fit of the resulting second-order response surface function to determine the optimal value of obtaining a stable point.