中文摘要：

为研究城市交通系统中宽扁梁的动力性能，由明德林（Mindlin）板理论退化得到板梁的控制方程，并推导出两端简支和两端固支板梁的自由振动特征方程，然后分别求解其自振频率和模态，并将计算结果与铁木辛科（Timoshenko）梁、Mindlin板的结果进行对比，总结板梁方程的梁宽适用范围并考虑泊松比对宽梁自由振动的影响。分析表明：相较Timoshenko梁方程，板梁方程更贴近Mindlin板的计算结果，尤其是前5阶自振频率，更适于较大泊松比的宽梁结构动力分析。

英文摘要：

To study the dynamic analysis of plate-beam,the governing equations are derived from the Mindlin plate theory,the characteristic equations of simply-supported ends and clamped-clamped beam ends are obtained respectively.Then,the natural frequency and normal mode are calculated and compared with those of the Timoshenko beam and Mindlin plate,a suitable range of length-to-width ratio is concluded for the application of the plate-beam theory and the influence of Poisson's ratio on the free vibration of wide beam.As theresult,the plate-beam theory is proved to have better agreement with the Mindlin plate theory rather than the Timoshenko beam equations,especially for the first five frequencies.