Wind-resistant Performance Analysis And Structural Parameters Optimization Of Truss Arch Light Steel Plastic Greenhouse

The truss-arch plastic greenhouse has been widely applied to agricultural production in northeast region with the advantage of simple structure,convenient construction and destruction,low maintenance cost.However,in the rapid development of plastic greenhouses at the same time,inevitably there are some quality accidents and security issues.The common phenomenon is that trussed-arch plastic greenhouse can collapse by the action of a storm.The reason is that the characteristics of skeletons is insufficient bearing capacity,unreasonable designed.At present,there is not a clear reference to the relevant norms of greenhouse structure in our country,which makes the construction of greenhouses lack design basis,and greenhouse design is not standardized.Currently,the size and shape of the greenhouse is considered important in design of greenhouse,while safety and durability is not considered.Many plastic greenhouses are designed,manufactured and installed by some non-qualified factories.Thus,the shape of greenhouses is various,the quality of greenhouses is different,both are not up to standard.Based on the current situation of greenhouse wide application and poor quality,on the investigation of Daqing arch plastic greenhouse,the present situation and existing problems in the construction of greenhouses were analyzed,and the truss arch plastic shed finite element model was established.The stress and displacement of the frame under the wind load were calculated,and the optimization design of truss arch steel frame was operated.The main work is as follows:(1)The investigation of the arch plastic greenhouse in Daqing was conducted,the structure type,the present situation and existing problems of greenhouse in Daqing were given.(2)The finite element calculation software of ANSYS was used to establish the skeleton model of the dominated truss arch plastic greenhouse in Daqing.Based on the Structural Mechanics Solver software,the calculation results of stress and displacement under the wind load standard value are compared.The finite element results of are in good agreement with Structural Mechanics Solver software result.So it is reliable to use the finite element method to calculate the force of the greenhouse skeleton model.(3)The stress and the displacement under the wind load standard value of the frame model of the truss arch steel frame are analyzed.Through the comparison of Code for design of steelstructures(GB 50017-2003),the results show that the greenhouse skeleton with the span of 6m,8m,10 m and 12 m does not exceed the allowable displacement subjected to the10-year-occurrence wind load.The stress of the greenhouse skeleton subjected to the10-year-occurrence wind load and both stress and displacement of the greenhouse skeleton subjected to the 30-year-occurrence wind load and the 50-year-occurrence wind load all exceed the allowable value.Therefore,the safety of greenhouse can not be guaranteed.(4)By using finite element optimization procedures,Optimum design of structural parameters for truss arch light steel plastic greenhouses was proceeded.The variable are cross-section diameter and wall thickness of the upper greenhouse chord,bottom chord and the web chord.The result of the optimization is to minimize the total steel consumption of the greenhouse skeleton under the condition that the maximum stress,maximum displacement of X direction and Y direction of the greenhouse do not exceed the allowable value,thus economic burden for the greenhouse users will be relieved.