火灾下钢框架结构热-力耦合模拟与性能分析

基于"自然火灾安全概念"(NFSC)的基本思想,提出了火灾下钢结构热-力耦合模拟方法。利用ANSYS的参数化设计语言,建立了ANSYS软件与OZone火灾分析软件的数据接口,实现了火灾分析软件与大型有限元软件的耦合运用。基于火灾模拟软件OZone的分析结果,利用APDL语言,对钢框架结构进行了真实火灾场景下的热-力耦合模拟。研究表明:钢框架结构在真实火灾场景下,受非均匀变热流影响,结构内部将产生热应力梯度和应力牵移现象;同时钢框架中钢梁固接时,火灾初期变形较小,当达到某个关键时间点后将开始大的变形破坏,其主要原因是钢框架内部产生塑性铰,即钢梁由固接变为铰接,释放了对钢梁的约束。

Thermo-mechanics Coupling Numerical Simulation of Steel-framed Structures on Fire and Its Performance Analysis

Based on natural fire safety concept(NFSC),the method for thermo-mechanics coupling numerical simulation of steel-framed structures on fire was established.By use of ANSYS parametric design language(APDL),a data interface was achieved between ANSYS and fire analysis software Ozone,and the coupling application of Ozone software with large-scale finite element software was realized.Based on Ozone and APDL,a thermo-mechanics coupling simulation of steel-framed structure on fire was conducted,the result shows that there exists a thermal stress gradient and stress transport phenomena in the inner of the steel-framed structure due to the effect of non-uniform heat flows,and that when the steel beam ends were fixed,the structure has only a small deformation at the beginning of the fire and a large one after a key point of time,main cause is that there produces a plastic hinge in the inner of the structure.Namely,the structure releases the constraint to steel beams due to the change of their connection from fixation connection to hinge connection.