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在传递屋面风荷载的过程中,金属复合屋面板的有限刚度和阻尼特性会改变脉动风的频谱特征,从而影响屋盖结构的风致振动效应.针对75mm和100mm两块典型跨度聚氨酯夹芯屋面板足尺试件,通过数值模拟和试验测试对其动力特性进行研究.基于已有聚氨酯夹芯材料的试验数据,建立了两块屋面板的初始有限元模型,并对其模态特征和阻尼性能进行了初步分析.参照分析结果,开展屋面板足尺试件的动力试验,利用PolyLSCF法识别得到屋面板的模态参数值.测试结果表明,聚氨酯夹芯金属复合屋面板试件的前7阶固有频率在24Hz~60Hz之间,频率分布密集,各阶模态阻尼比在1%~3%之间.以试验识别的固有频率和振型为基准,采用一阶优化方法对初始有限元模型进行修正.分析发现聚氨酯夹芯材料的竖向弹性模量、密度和泊松比是影响屋面板动力特性的敏感参数,支承檩条对屋面板动力特性的影响也不能忽略.将檩条引入初始模型并再次进行模型修正,最终获得的屋面板各项设计参数修正值均保留明确的物理意义,可供此类屋面板的风致振动效应分析及相关研究采用.
In the process of transferring the roof wind load, the limited stiffness and damping characteristics of the metal composite roofing panel can change the spectral characteristics of the pulsating wind and affect the wind-induced vibration effect of the roof structure. For two 75mm and 100mm typical span polyurethane sandwich panels Full-scale specimens were used to study their dynamic characteristics through numerical simulation and experimental tests.According to the experimental data of polyurethane core material, the initial finite element model of two roof panels was established, and its modal characteristics and damping properties According to the results of the analysis, the dynamic test of the full-scale roofing panel was carried out and the modal parameters of the roofing panel were identified by the PolyLSCF method.The test results show that the first seven stages of the polyurethane sandwich panel The natural frequency is between 24Hz and 60Hz, and the frequency is densely distributed, and the modal damping ratio of each order is between 1% and 3% .According to the natural frequency and mode shape of the experiment, the first-order optimization method is used to analyze the initial finite element model .The results showed that the vertical modulus of elasticity, density and Poisson's ratio of polyurethane core material are sensitive parameters that affect the dynamic characteristics of roofing panel, The influence of sex can not be neglected.When the billet is introduced into the initial model and the model is modified again, the final revised values of the design parameters of the roofing panel retain the explicit physical meaning, which can be used for the wind-induced vibration effect analysis and related research use.