Applicability of complete geometric nonlinear model and one-order approximate nonlinear model in the case of large deformation was investigated by rigid-flexible coupling experiments for dynamic system composed of air-bearing test bed and elastic beam. Firstly, based on nonlinear relation between Green strain and displacement, complete geometric nonlinear model for an elastic beam was established by using absolute nodal coordinate formulation. Considering structural damping, rigid-flexible coupling dynamic equations for the multi-body system composed of air-bearing test bed and elastic beam were derived, and then using the non-contact motion measuring instrument and strain measuring instrument, velocity, angular velocity and strain of points of the beam were measured to verify the correctness of the complete nonlinear model by comparison of the theoretical and experiment results. Furthermore, applicability of one-order approximate nonlinear model based on small deformation theory was investigated.%通过气浮台和梁系统的刚-柔耦合动力学实验研究完备的几何非线性模型和一次近似模型在大变形情况下的适用性.首先从Green应变与位移的非线性关系式出发,用绝对节点坐标法建立了弹性梁的完备的几何非线性动力学模型,并考虑结构阻尼建立了气浮台和梁系统的刚-柔耦合动力学方程,然后利用非接触式的运动测量仪和应变仪测量特征点的速度、角速度和应变,通过理论和实验结果的数值对比验证了几何非线性动力学模型的正确性,在此基础上进一步分析基于小变形的一次近似模型的适用性.
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