界面掀起和轴力对组合梁动力弯曲特性的影响

考虑组合梁界面的法向/切向部分相互作用以及各子梁轴力的二阶效应，利用Hamilton原理得到了位移描述的Euler-Bernoulli组合梁非线性动力弯曲及一阶近似的初边值问题，并应用微分求积法研究了考虑界面法向/切向部分相互作用组合梁的临界荷载和固有频率。在通过与已有解析解和有限元结果对比验证了本文微分求积法正确性和适用性的基础上，进行了参数分析，研究了组合梁界面刚度对组合梁动力特性和稳定性的影响以及轴力对组合梁固有频率的影响。数值结果表明：组合梁的固有频率与临界荷载随界面刚度的增加而增加，并逐步趋于完全作用组合梁的固有频率与临界荷载；当轴向压力逐渐增加并趋于临界载荷时，组合梁的一阶固有频率逐渐减小并趋于零，并且，临界载荷随法向和切向刚度的增加而增加。

INFLUENCES OF THE INTERFACIAL UPLIFT AND AXIAL LOAD ON DYNAMIC BENDING CHARACTERISTICS OF COMPOSITE BEAMS

Taking into account the normal/tangential interfacial partial interaction and the second-order effect of axial load of each sub-beam, displacement-based nonlinear and first order approximate initial-boundary value problems for the dynamic bending of the Euler-Bernoulli composite beam, by virtue of the Hamilton’s principle, are formulated, and then the buckling load and natural frequencies of the composite beam with partial interaction are investigated by the differential quadrature method (DQM).  On the basis of the correctness and validaty of the proposed DQM verified via the comparisons with the analytical solutions available and FEM ones, the parameter study is conducted, and the influences of the interfacial stiffness on dynamic characteristics and stability and the effects of the axial force on the natural frequencies are studied.  The numerical results show that the natural frequencies and buckling load of the composite beam increase with the increase of its interfacial stiffness, and eventually approaching to the ones of full composite beam, and the first natural frequency decreases to zero with the increase of the axial load approaching to the buckling load.  And furthermore, the critical load increases with the the interfacial normal and tangential stiffness increase.