钢箱梁加劲板局部动力性能设计参数研究

摘要

为了解钢箱梁加劲板局部振动的特性以及结构与材料参数对其动力性能的影响规律,指导结构设计,以常见的钢箱梁梯形肋加劲板为例,基于有限元软件ANSYS二次开发,建立有限元模型(母板、横隔板与梯形肋的各个板件均用Shell63单元模拟,铺装层采用8节点实体板单元模拟),计算其基本动力特性,分析梯形肋的数量及厚度、横隔板数量、母板厚度、铺装层厚度等设计参数对加劲板自振频率的影响.结果表明:加劲板的2阶自振频率相比于1阶显著提高,之后阶次的增幅相对平缓,且四边固支的自振频率大于四边简支的自振频率,设计时加劲板的基频与高阶频率应分开考虑,且无需详细考虑每一阶高阶振动;合理确定梯形肋与横隔板的位置比增加数量更能有效提高相应的自振频率;母板、梯形肋与铺装层厚度的变化对自振频率的影响不明显,建议在设计规范的范围内取较低值.%To examine the local vibration property of the stiffening plates of the steel box gird-er and the influential law of structural and material parameters on the dynamic performance of the stiffening plates and to guide the structural design as well,the conventional trapezoidal stiffening plates of steel box girder are taken as examples.Based on the secondary development of the finite element software ANSYS,the finite element model of the stiffening plate was established to calcu-late the fundamental dynamic properties and analyze the influence of design parameters,such as the amount and thickness of the trapezoidal stiffening plates,the amount of diaphragms,the thick-ness of the base plate and the thickness of the pavement,on the natural vibration frequency of the stiffening plates.The base plates,diaphragms and the stiffening plates were modeled by the Shell63 element,and the pavement was modeled by the eight-node solid plate element.The results show that the second order natural vibration frequency of the stiffening plate is markedly improved compared with the first order.The increment of the subsequent orders was relatively flat.The natural vibration frequency of the four-side fixed structure is greater than that of the four-side sim-ply-supported structure.During the design process,the basic frequency of the stiffening plate and the higher order frequencies should be considered separately,and the higher order vibration of each order does not need detailed consideration.Compared with the way of increasing the amount of trapezoidal stiffening plates and diaphragms,proper installation locations are more efficient to the improvement of the natural vibration frequency.Thickness variation of base plates,trapezoidal stiffening plates and the thickness of the pavement have no obvious influence on the natural vibra-tion frequency,and it is suggested to draw the lower values within the range prescribed in the de-sign code.