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基于ANSYS数值模拟结果,首次对铝合金梁在火荷载作用下的响应行为进行模拟。系统比较了简支、铰支、固支、一端固支另一端简支等几种典型边界约束条件下铝合金梁的抗火特性,着重讨论了各自的临界温度并与已有规范进行了对比,在此基础上考察了端部约束条件、载荷比、载荷类型等因素对铝合金梁弯曲屈曲失效行为的影响。结果表明:设计规范公式计算出的临界温度偏于保守,比有限元结果低2.5%~16.7%,而有限元更能反映真实情况;对于不同的约束情形,铰支梁的抗火能力最强,其次是固支梁,简支梁的抗火能力最差;载荷比越大,铝合金梁的临界温度越低,抗火能力越弱,载荷比由0.3增加到0.7时,简支梁和一端固支另一端简支梁的临界温度减小约43℃,固支和铰支梁的临界温度分别减小37℃和30℃;载荷类型对铝合金梁的影响较小。本文研究为铝合金结构抗火设计提供了理论依据。
Based on the numerical simulation results of ANSYS, the response behavior of aluminum alloy beam under fire load was simulated for the first time. The anti-fire properties of aluminum alloy beams under several typical boundary conditions, such as simple support, hinged support, fixed support and simple support at one end, are compared systematically. Their respective critical temperatures are discussed in detail and compared with the existing specifications Based on this, the influence of end restraint conditions, load ratio and load type on bending buckling failure behavior of aluminum alloy beams was investigated. The results show that the critical temperature calculated by the design specification formula is conservative, which is 2.5% ~ 16.7% lower than the finite element result, while the finite element can better reflect the real situation. For different constraints, the fire resistance of the hinged beam is the strongest , Followed by the fixed beam, simply supported beam of fire resistance is the worst; load ratio is larger, the lower the critical temperature of the aluminum beam, the weaker the fire resistance, the load ratio increased from 0.3 to 0.7, The critical temperature of the simply supported beam with one end supported and the other end reduced by about 43 ℃ and the critical temperature of the fixed and hinged beams decreased by 37 ℃ and 30 ℃ respectively. This study provides a theoretical basis for the fire-resistant design of aluminum alloy structures.