Indoor-fire Temperature Field And Mechanical Properties Of Steel Structures In Fire

Fire precaution and fighting is an arduous work for man all the way. In recent years, structural fire-resistance becomes one of the most important and complex theme in the field of structure works. With the rapid development of national economy, steel structures are becoming widely used because of their light deadweight, high strength, rapid construction and good aseismatic performance. Due to the great change of physical and chemical properties of steel under the circumstance of high temperature which lead to big loss of strength of steel members, great importance are attached to the steel structures in a fire by the researchers.The essay talks mainly about indoor-fire temperature field and mechanical property of steel members in fire. After a brief introduction of indoor-fire development process, heat transfer process and common-used methods of computer simulation of indoor-fire, a computational model of indoor space is established on base of which combustion parameters and boundary conditions such as heat source and ventilation are imported. Afterwards, the hydraulic model of indoor hear transfer is established. In accordance with heat release rate in an actual fire, a time-dependent heat release model is employed in the essay. With the aid of numerical analysis of hydraulics, the temperature field which varies from point to point of an indoor space is obtained. At the same, we can see the fluid field. The numerical data distinctly express the distribution of heat and the flow of air, which realize the structural analysis in high temperature and resistance of fire. The temperature field is placed upon an experimental steel member in succession, combining with the research of physical and chemical properties of steel which have been discussed. Finally, the mechanical properties which include stress, strain and displacement are calculated. In contrast with the stress, strain and displacement of the above member in normal temperature, a conclusion is reached that the influence of high temperature to steel structures is tremendous.A reliable anti-fire design of a structure is important and necessary after realizing the occurrence of structural fire and its great damage to the structure. Therefore, the temperature field of an indoor-fire and the mechanical property of main bearing members in fire should be illuminated as basis of further research before an anti-fire research. Due to the complexity of factors which influence the distribution of heat and high expense of fire resistance experiments, the numerical simulations of fire-site which can be regarded as means of assistant design become more and more necessary and feasible. The work done by this essay is a helpful trial to the numerical simulation of temperature field and offers elementary distribution data for anti-fire research of steel structures.