高速磁浮整体式预应力轨道梁温度场与变形分析

Temperature field and deformation of high-speed maglev prestressed overall guideway beam

轨道梁日照作用与列车荷载下的热力耦合变形是高速磁浮轨道梁设计时需要考虑的重要因素之一。根据传热学理论,结合青岛地区夏季气象数据与日照辐射半经验公式给出日照辐射分布场,基于ABAQUS建立青岛高速磁浮试验线整体式预应力混凝土轨道梁三维有限元瞬态分析模型,研究变截面轨道梁纵向温度分布规律、竖向与横向最大温差时刻温度梯度分布,并以指数函数为基础拟合得到温度梯度曲线,给出在三维梁模型中的温度分布场。利用顺序热力耦合方法开展热力耦合作用对轨道梁变形影响的数值仿真研究。热力耦合仿真结果表明,轨道梁最大竖向温度梯度出现在下午14:00,同时刻热力耦合工况下轨道梁跨中挠度最小,最小值为3.150 mm。凌晨01:00时刻,轨道梁跨中挠度最大,最大值为3.336 mm。横向位移极值分别出现在上午11:00和下午15:00,位移极值分别为1.237 mm和1.515 mm。预应力筋对轨道梁跨中竖向挠度影响显著,预应力水平为1302 MPa的轨道梁跨中挠度比无预应力的轨道梁要少23.96%;预应力筋对轨道梁横向变形影响不明显,预应力水平为1302 MPa的轨道梁横向变形与无预应力的轨道梁仅相差0.2%。

The coupling deformation between guideway beam and vehicles is one the most important factors in the design high-speed maglev guideway by considering the thermal-mechanical interaction effects.The solar radiation distribution field in Qingdao city was presented,based on the heat transfer theory,the summer meteorological data in Qingdao and the semi empirical formula of sunshine radiation.And a three-dimensional model of the prestressed overall guideway beam for Qingdao maglev test line was proposed in ABAQUS.The temperature distribution of the longitudinal,vertical,and transverse temperature difference of the girder was analyzed,according to the transient state analysis method.The corresponding temperature gradient curves were fitted based on the exponential function.The numerical simulation of thermal-mechanical coupling on guideway beam was carried out by using the sequential thermal-mechanical coupling method.According to simulation results,the maximum vertical temperature gradient of the guideway beam appears at 14:00 PM.Under the thermal-mechanical coupling effects,the deflection of the guideway beam is the smallest at 14:00 PM,and its value is 3.150 mm.The largest deflection is 01:00 AM,and its value is 3.336 mm.The extreme value of lateral displacement appears at 11:00 AM and 15:00 PM,its values were 1.237 mm and 1.515 mm respectively.The prestressed rebars have a significant influence on the deflection of the guideway beam.The deflection of the guideway beam with a prestress level of 1302 MPa is 23.96%smaller than the one without prestress.The prestressed rebars have no influence on the lateral deformation of the guideway beam.The lateral deformation of the guideway beam with a prestress level of 1302 MPa is only 0.2%different from the one without prestress.