主动约束层阻尼梁结构复杂耦合振动的多层谱有限元法

Multi-layer Spectral Finite Element Method for Beams Fully Treated with Active Constrained Layer Damping

针对全主动约束层阻尼(ACLD)覆盖的梁结构复杂耦合振动特性,采用一种新型的多层谱有限元法(MLSFEM)进行研究.该方法的特点是可避开采用谱有限元法时须求解带未知参数的高阶特征方程的困难,同时又保持谱有限元法使用很少单元却高精确度的优点.对典型算例使用该法的计算结果与采用谱传递矩阵法(STMM)获得的相应精确结果作了比较,证实了MLSFEM用于ACLD梁结构的有效性与精确性.还分别采用位移负反馈和速度负反馈两种控制策略,研究控制增益与ACLD梁结构动力特性之间的关系.结果表明,两种反馈控制策略对ACLD梁结构动力特性有着显著不同的影响.

A new type of spectral finite element method (SFEM), called multi-layer spectral finite element method (MLSFEM), was employed to study the complicated and coupled vibration characteristics of beams fully treated with active constrained layer damping (ACLD). Its formulation shows that it need not to solve the characteristic equation with higher orders and unknown parameters for wave numbers when using the SFEM, and keeps advantages of a very few elements and high accuracy of the SFEM. Compared with the corresponding accurate results by using the spectral transfer matrix method (STMM), the results of a typical example by use of MLSFEM demonstrate the effectiveness and accuracy of this new approach. With different control strategies including negative feedback of the displacement and velocity of the free end of the cantilever base beam, the effects of control gain on the frequency response function (FRF) of the beam/ACLD system were also studied. The results show that different control strategies have very different effects on the dynamic characteristics of the beam/ACLD system.