Study On Temperature Field And Temperature Effect Of Continuous Welding Stainless Steel Roof System

The large-span metal roof system has the characteristics of a complex structure,large span,and light material,which has been widely used in various landmark buildings.The metal roof system has been exposed to the outdoors for a long time.Under the intense solar radiation and significant temperature difference,the metal roof system will produce a noticeable temperature effect,which should be paid attention to in engineering design and application.The research on the metal roof system mainly focuses on the wind resistance performance and the connection performance of key nodes.There is a lack of research on the temperature field and temperature effect of the metal roof system,and there is little research on the related test methods and theoretical calculations.Therefore,this paper selects the typical continuous welded stainless steel roof system in engineering to analyze the temperature field and temperature effect.The research of this paper has essential reference value and data support for the design and application of engineering and the compilation of relevant specifications.The main works and results are as follows.1.A wireless monitoring system for temperature and environmental parameters of stainless steel plates was established.Based on long-term real-time monitoring data,the correlation analysis between the temperature of two stainless steel plates and ambient temperature,light intensity and ambient wind speed was carried out.The effects of different sizes,surface treatments,tilt angles and spatial placement positions on the temperature field distribution of the two stainless steel plates were considered.The results show that the maximum errors between the wireless monitoring results and the manual monitoring and finite element analysis results are 3.4% and 7.2%,respectively.The temperature of stainless steel plate is positively correlated with ambient temperature and light intensity,and negatively correlated with ambient wind speed.The correlation coefficient with ambient temperature is the largest,and the correlation coefficient with ambient wind speed is the smallest.The temperature difference between the stainless steel plate temperature and the ambient temperature in the high temperature,medium temperature and low temperature ranges is more than 30 °C,and the maximum difference of the stainless steel plate temperature in each range is 47.2%.Different inclination angles have a great influence on the temperature of stainless steel plate,and the maximum temperature difference can reach more than 10 °C,while the surface treatment and spatial placement position have little influence on the temperature of stainless steel plate,and the maximum temperature difference is about 5 °C.2.The temperature field distribution and transfer characteristics of each structural layer of the continuous welded stainless steel roof system,the stress distribution law of the main stress components,and the relationship between the ambient temperature and the stress of each component are measured and analyzed,and the theoretical calculation formula of the temperature field suitable for the surface roof panel of the roof system is derived.The results show that the temperature of each structural layer of the roof system is significantly higher than the ambient temperature,and the temperature of each structural layer generally shows a downward trend,with the maximum temperature difference of 28.4 °C.The temperature stress at the positions of purlin,support,slab surface and slab rib increases linearly with the ambient temperature,and the linear fitting coefficients are all above 0.90.The maximum error between the measured and theoretical results is 8.9%.3.The static and dynamic temperature field loading test methods for stainless steel roof system are proposed.Based on the measurement,test and finite element analysis,the selection of heating rate,constant temperature time,temperature gradient,average and maximum temperature difference,cycle times and other parameters are determined.The results show that the temperature gradient,average temperature difference and extreme temperature difference in the static temperature field loading test method are set to 20 °C,60 °C and 80 °C,respectively.The constant temperature time can be set at 15 min ～ 30 min.When the constant temperature time exceeds 30 min,the maximum influence on the temperature effect of the roof system is 2.6%.The heating rate is recommended to be set at about 2 °C/min,and the difference between the test and the measured results at the heating rate of 2 °C/min is the smallest of 8.3%.The number of cycles in the dynamic temperature loading test method is recommended to be no less than 4 times.The residual stress and displacement mainly occur in the first 4 cycles,accounting for more than 70% of the overall change range.4.Based on the static temperature field loading test method,the temperature effect of stainless steel roof system in practical engineering is studied,and the influence of constraint form and roof system structure form on temperature effect is considered.The results show that the change of constraint form has a significant effect on the stress and displacement of the vertical seam stainless steel roof system,and the maximum influence ranges are 41.7 % and49.6 % respectively.The temperature stress and displacement difference between the two roof systems can reach more than 70%.The maximum difference between the stress and displacement of the continuous welded stainless steel roof system and the standing seam stainless steel roof system is 73.7% and 77.8%,respectively.