The mass matrix and the coupling matrix of bending and torsion vary with the time concern to the deflections of the system when the nonlinear inertial term and the geometric non - linearity term are comprised in the dynamic formulation 文中推导的动力学有限元方程中的一致质量矩阵m和弯扭耦合矩阵?都考虑了几何非线性项和非线性惯性项，因此是与系统变形有关的时变矩阵。
