火灾下弦支穹顶结构热力学响应试验研究OA

To investigate the mechanical responses of large-space structures under fire conditions,a 1/5-scale suspendome model with a span of 12 m and a height of 2 m was designed and constructed to perform fire tests under varying fire source powers and ventilation conditions.The objectives were to characterize the air temperature field,the temperature distributions of components,and the mechanical response during fire.The experimental results demonstrate that the internal air temperature field exhibits pronounced spatial non-uniformity under fire conditions.As the fire source power increases from 143.20 kW to 358.00 kW and the opening factor decreases from 0.14 m1/2 to 0.04 m1/2,the maximum internal air temperature rises from 67.30℃to 183.92℃,with an increase of approximately 173.28%.Under a fire source power of 358.00 kW,the maximum structural deformation does not exceed 6 mm,remaining within the elastic range and below the displacement limit specified in JGJ 7-2010'Technical specification for space frame structures',indicating a high overall stability.Under fire conditions,all hoop cables of the suspendome structure relax due to thermal expansion,resulting in a decrease in prestress of 1.30%to 48.11%.The outer hoop cables show the highest rate of prestress reduction,while the inner hoop cables experience a smaller rate of reduction.The FDS field simulation method can effectively calculate the air temperature inside the structure under fire conditions,and the finite element analysis model can effectively predict the structural response under fire conditions.