Experimental Research And Theoreticalanalysis On Working Performance For Continuous Welded Stainless Steel Metal Roofing System Subject To Temperature Cycling

The metal roofing system is more and more widely used as the perimeter protection system of large-span structures because it can flexibly adapt to buildings with irregular and complex shapes.Among them,the upright edge seam metal roofing system is the most widely used,but in the process of construction and use,there are still problems to be solved,such as temperature effect,wind lift failure,roof leakage,fire hazards and so on.At present,domestic and foreign scholars have carried out a comprehensive study on the problems of wind lift failure,roof leakage,fire hazards,etc.,but relatively little research has been done on temperature effects.Moreover,the influence of thermal stress on the mechanical properties of each component of the roof system is generally not considered when designing the metal roof.The analysis of the temperature effect of the structure is basically a qualitative analysis or a simple quantitative analysis calculation.The structure design is often not economical and reasonable,and it lacks an accurate quantitative calculation of the temperature effect.This project adopts a 0.5mm thick continuous welding stainless steel metal roofing system.The roofing material is made of ultra-pure ferritic stainless steel TTS445J2 with good durability.The roofing connection method is full welding.This system,as the perimeter protection structure of a large-span building,has been affected by factors such as solar radiation and external ambient temperature for a long time,resulting in temperature deformation.When the temperature state changes,due to other constraints such as fixed supports,the deformation of the metal roof slab will be limited,thereby generating temperature stress inside the structure.Therefore,it is necessary to study the temperature effect of continuous welding stainless steel metal roofing system.The main research work in this paper is as follows:(1)The application status,existing problems and development directions of domestic metal roofing systems are discussed.The research status of temperature effects analysis of long-span steel structures at home and abroad is discussed.(2)The types and characteristics of temperature effects in engineering structures are introduced;the basic theories of temperature field analysis and temperature stress analysis are elaborated;four basic assumptions are proposed for the temperature effects of the structures studied.(3)The material mechanical property test was performed on the base material of stainless steel roof slabs.The experimental research results show that there is no yield stage in thetensile process of stainless steel materials,and the failure form of the material specimen after breaking is that the shear position is about 45 ° Cut type damage.(4)Taking the continuously welded stainless steel metal roofing system in the lobby of the F area of the Qingdao-Jiaodong International Airport as the research object,9 high and low temperature cycle experiments were performed on the model specimen of its substructure.The results of the experimental study showed that no obvious deformation of the stainless steel roof slab,no loosening of self-tapping screws between the stainless steel fixed support and the substructure,and between each layer of steel plate.At the same time,the stress measurement of stainless steel roof panels and fixed supports and the incremental measurement of the surface displacement of roof panels were performed.The results show that as the number of temperature cycles increases,the measured data of the same loading temperature point under different cycles has less fluctuation.It shows a relatively stable trend,and the weather resistance of the test piece is good.(5)Based on the ABAQUS / Standard module,a finite element model of a model test for a continuous welded stainless steel metal roof system was established,and the deformation and stress performance of various components of the system were analyzed.The comparison between numerical simulation results and experimental results verifies the correctness and adaptability of the finite element model.(6)According to the original standard construction design of the roofing system,based on the simplified size of the continuous welded stainless steel metal roofing system model test piece.Using the same finite element modeling method,the influence of two parameters of the thickness of the stainless steel roof slab and the width of the weld seam on the temperature effect of the test specimen of the roofing system model is studied.