螺栓松动边界下纤维增强复合薄板固有特性分析

通过人工弹簧刚度法对螺栓松动边界下纤维增强复合薄板的固有特性进行了分析。首先,为了研究螺栓松动边界的影响,人为地在复合薄板的约束端引入多组弹簧来模拟不同程度的螺栓松动边界,并建立了此类型边界下复合薄板的理论模型。然后,采用正交多项式法建立薄板自由振动的振型函数,并通过Ritz法对方程进行求解,计算此边界下薄板的固有频率和模态振型,给出具体的计算流程。最后,设计并组配了带有预埋压力传感器的螺栓松动边界下复合薄板的振动测试系统,准确测试了螺栓松动不同程度边界下对应的固有频率和模态振型,将实验结果与理论分析结果进行对比,发现两者的振型形态基本一致,其固有频率的误差在0.08%～7.54%之间,属于误差允许的范围,从而验证了所提出方法的可行性。

Inherent Characteristics Analysis of Fiber-reinforced Composite Plates under Bolt Looseness Boundary

The inherent characteristics of the fiber-reinforced composite plates under the bolt looseness boundary were analyzed using artificial spring stiffness method. Firstly, in order to study the impacts of bolt looseness boundary, the multiple sets of spring were artificially introduced into the constraints of composite plates to simulate bolt looseness boundary of varying degrees, so that the theoretical model of the thin plates under this complex boundary was established. Then, based on the orthogonal polynomial method, a free vibration mode function of thin plates was expressed. The inherent frequency and modal shapes under bolt loosening boundary were solved by Ritz method, and the specific calculation procedure was also proposed. Finally, a vibration test system of the composite plates was set up with an embedded pressure sensor under bolt looseness boundary. The corresponding inherent frequencies and modal shapes under different bolt looseness boundaries were measured accurately. After the comparison between experimental and theoretical analyses, the results show that their modal shape results are coincidence with each other, and the errors of inherent frequencies are in the range of 0.08% and 7.54%, which are in an acceptable level. Therefore, the correctness of the proposed theoretical method was verified.