正交加筋板中板梁耦合动力特性

Dynamic coupling characteristics of the beam and plate components of the orthogonally stiffened plate

[目的]旨在探究正交加筋板中板梁构件的动力耦合关系及其对正交加筋板本征动力特性的影响机理和影响规律。[方法]以不同弯曲刚度比的正交加筋板模型为研究对象,采用有限元法计算自由边界和固支边界下正交加筋板模型的固有频率及振型,通过分析正交加筋板模型的固有频率及振型随板梁弯曲刚度比的变化规律,探究正交加筋板中加强筋与平板两种构件间的动力耦合特性。[结果]研究表明,在板梁构件弯曲刚度变化过程中,正交加筋板主要表现为板类动力特性为主导和板梁耦合动力特性两种形式。得到了这两种形式转变过程中的临界板梁弯曲刚度比及其判据。[结论]板梁动力耦合现象对固有频率的影响主要表现为改变固有频率随弯曲刚度比的变化速率,对固有振型的影响主要表现为使板类振型产生错位分布和形态畸变。

[Objective]Orthogonally stiffened plates with different plate-to-beam bending stiffness ratios are taken as the research objects to uncover the dynamic coupling characteristics of the beam and plate compon-ents of orthogonally stiffened plates,and reveal the mechanism and influence of dynamic coupling between the construction members on their intrinsic dynamic characteristics.[Method]The natural frequencies and mode shapes of numerical models under free boundary conditions and clamped boundary conditions are calculated using the finite element method.Through an analysis of variations in the natural frequencies and mode shapes of an orthogonally stiffened plate against the plate-to-beam bending stiffness ratio,the intrinsic dynamic char-acteristics of an orthogonally stiffened plate with different bending stiffness ratios are discussed,and the dy-namic coupling characteristics between the beam and plate are analyzed.[Results]The numerical results show that with the variation of the plate-to-beam bending stiffness ratios,the dynamic behaviour of the orthogonally stiffened plate transforms between two kinds of characteristics:one dominated by the plate and the other one coupled by the beam and plate.The critical plate-to-beam bending stiffness ratios and the criterion for determ-ining them are presented in this paper.[Conclusion]The dynamic coupling between the beam and plate changes the variation rate of the natural frequencies with the plate-to-beam bending stiffness ratio,leading to the dislocation and distortion of the mode shapes of orthogonally stiffened plates.