箱梁梁格法建模若干问题的探讨

Inquiry on box-girder-grid modeling problems

针对梁格法分析箱梁结构存在的问题,分析了纵向梁格的划分方式,横向梁格的截面形式,不同的单元尺寸对计算结果的影响。通过实例分析,以ansys实体模型的计算结果为标准,比较不同建模方式的计算精度。结果显示,纵向梁格采用等分顶、底板的方式比在腹板间对中切开的方式计算结果精确。在三种不同工况的作用下,支座反力的最大误差仅为9.4%,挠度最大误差仅为3.1%。横向梁格采用工字形截面比矩形截面计算结果精确。通过实例论证,为以后的梁格法建模提供了一个简单可行又能满足精度要求的方法。

This paper introduces the grillage analogy method of box girder.Analyze the impact of different longitudinal grillage section,transverse grillage section and element size.Through the example,take the result of ansys model as standard,comparing the accuracy of different modeling methods.Results show that,portrait grillage section using the way of dividing top and bottom flange equally produce smaller error than cutting between adjacent webs.under three different working condition,the maximum error of reaction force is 9.4%,the maximum error of deflection is just 3.1%.it is also more accurate when the landscape grillage take theⅠ-shaped section than the rectangular section.By calculation expression this paper provides a not only easily practicable but also accurate way for grillage analogy method.