【作者】 张雯；

【导师】 颜卫亨；

【作者基本信息】 长安大学 ， 结构工程， 2019， 硕士

【摘要】 平面腹部凸出的双坡房屋在我国野营房屋及民用房屋中得到广泛应用,然而目前的设计规范尚未给出这种体形的积雪分布系数,其结构抗雪设计往往仅能近似参考双坡屋面,尤其当这类房屋自重较轻时,属于对风雪荷载敏感的结构,其设计可能存在安全隐患,因此对平面腹部凸出双坡房屋的积雪规律及积雪分布系数进行研究及探讨,可为规范提供理论依据及工程设计应用,具有较好的理论意义及工程价值。基于计算流体动力学原理和两相流理论,运用ICEM CFD软件进行数值建模,采用FLUENT软件中的Mixture多相流模型对立方体及高低屋面的风致雪漂进行数值模拟,并与实测数据进行对比,分析与探讨参数选取及边界条件设置。对平面腹部凸出双坡房屋进行风致雪漂数值风洞试算,得到屋面积雪分布规律的基础上,设计出3种分析模型及屋面的分区划分,以风向角0°、45°、90°、135°、180°,风速5m/s、7.5m/s、10m/s、12.5m/s、15m/s,及屋面坡角20°、31°、40°为变量参数的195种工况的风致雪漂移运动进行数值模拟分析,得到各工况下房屋屋面风致雪漂分布规律及可供抗雪设计的各分区积雪分布系数。研究结果表明:随着模拟时长的增加,各分区的积雪侵蚀程度都普遍增加,迎风区表现的较为明显,背风区相对比较缓和,说明迎风区比背风区的积雪分布对风的作用更为敏感;在观察屋面积雪分布规律的基础上对房屋屋面进行分区,能更好反映积雪沿屋脊长度方向的分布特性,分区后屋面中部的积雪分布系数值超过不分区约9%,分区后的积雪系数值有利于荷载设计的安全性及合理性;当双坡房屋含有腹部凸出的过渡区域时,会增加背风区的积雪堆积程度,腹部凸块对主体结构影响明显,若仅参考双坡屋面积雪系数进行设计,存在安全隐患,设计人员应予以注意。更多还原

【Abstract】 The double-slope houses protruding from the plane abdomen have been widely used in camping houses and civil buildings in China.However,the current design specifications have not given the snow distribution coefficient of this shape,and the structural snow-resistant design is often only approximated by a single span.Double-sloping roofing,especially when the self-weight of such houses is light,is a structure sensitive to wind and snow loads,and its design may have potential safety hazards.Therefore,the snow accumulation law and snow distribution coefficient of the double-slope houses protruding from the plane abdomen are studied.And discussion,can provide theoretical basis and engineering design application for the specification,with good theoretical significance and engineering value.Based on the computational fluid dynamics principle and the two-phase flow theory,the ICEM CFD software is used for numerical modeling.The Mixture multiphase flow model in FLUENT software is used to numerically simulate the snow drift around the cube and compare it with the measured data.Discuss parameter selection and boundary condition settings.Based on the wind-snow drift numerical wind tunnel trial of the flat abdomen protruding double-slope house,based on the distribution law of the snow area of the house,three kinds of analysis models and the division of the roof are designed.The wind direction angle is 0°,45°,90°,135°,180°,wind speed drift of 195 kinds of working conditions with wind speeds of 5m/s,7.5m/s,10m/s,12.5m/s,15m/s,and roof slope angles of 20°,31° and 40°.The numerical simulation analysis of the motion obtained the distribution law of wind-induced snow drift on the surface of the house under various working conditions and the snow distribution coefficient of each zone available for snow resistance design.The results show that:with the increase of simulation time,the degree of snow erosion in all zones generally increases,the performance in the windward area is more obvious,and the leeward area is relatively moderate,indicating that the snow distribution in the windward area is more effective than the wind in the leeward area.Sensitive;detailed partitioning of the roof of the house can better reflect the distribution characteristics of the snow along the length of the ridge.The distribution coefficient of the snow in the middle of the roof after the partition is more than 9%than the non-partition.If the roof is not partitioned,the snow is covered.The coefficient value is not conducive to the safety and economy of the load design.Therefore,for the snow-sensitive structure,the roof should be partitioned to reveal its unfavorable snow distribution;when the single-span double-slope house contains the transitional area of the abdomen,it will Increase the accumulation of snow in the leeward area,and the abdominal bumps have obvious influence on the main structure.If only the snow coefficient of the single-span double-slope house is designed,there is a safety hazard,and the designer should pay attention to it.更多还原