基于Dirac函数原理的箱型梁剪力滞效应分析

Analysis of shear lag effect of box girder based on the principle of the dirac function

为了研究集中弯矩作用下箱型梁的剪力滞效应,建立了基于附加挠度的箱型梁总势能泛函,利用狄拉克函数一阶导数积分的性质推导了附加挠度的一般表达式和剪力滞系数解。算例对比分析表明:与传统的基于应力定义的能量变分近似计算方法相比,基于附加挠度定义的计算方法计算精度更高,并且能够有效处理箱型梁集中弯矩作用截面处引起的剪力滞系数突变,更真实地反映截面处的受力状态。

In order to study the shear lag effect of box girder under the concentrated bending moment,the potential energy functional was derived based on additional deflection.The generalized equation of additional deflection can be formulated in terms of first derivative of Dirac function.Meanwhile,the solution of shear lag coefficient can be given accordingly.By comparison study in a typical example,the proposed approach has been proved to have higher accuracy than the conventional method,which is usually based on energy variational method.And also,it can effectively resolve the issue of dramatical change of shear lag coefficient that often happens in the position of concentrated bending moment.Therefore,the corresponding results can reflect the more realistic strain and stress status of the section.