Study On The Structural Damping Behaviors Of Fiber Reinforced Composite Leaf Spring

Fiber reinforced polymer-matrix composites are widely used in aerospace, marine engineering and various civil applications, such as automobiles and so on, due to their exceptionally high specific stiffness and strength. The composites are known to exhibit material damping one or two orders higher than most common metals as a result of the high damping of polymer matrices and the material heterogeneity. And the significance of the damping to the dynamic performance of composites structures is broadly recognized in the recent years. Under the circumstances of high requirement to the structural damping of the composites in the engineering applications, the systemically experimental and theoretical study on the vibratioanl damping of the composites was accomplished in this paper, based on the cantilever beam method and the Finite Elemental Analysis (FEA).Nine groups of laminae and leaf springs made of glass-fiber/epoxy resin, glass-fiber/toughened epoxy resin and carbon-fiber/toughened epoxy resin were manufactured, and different mechanical experiments and vibrational damping tests were performed. The experimental tests were conducted to obtain the mechanical parameters and damping parameters of the laminae and leaf springs. And a half-power bandwidth-Matlab method was used to get the exact values of half-power bandwidth, according to the actural curves from the detectors. And the loss factors of the composite laminae and leaf springs were finally obtained through the calculation by equations. In the finite elemental analysis, the limit state equation for damping analysis of the composite leaf spring structure was set up according to the mode strain energy method and composite structural mechanics. On the basis of experimental results, numerical simulation procedure for the finite elemental analysis based on ANSYS software was complied, which realize the finite elemental design and analysis for the structural damping of the fiber reinforced polymer-matrix composite leaf springs. Good agreement was shown in the comparison between the analytical and experimental results.The study on the effect of the different layout and different constituents (including fiber and matrix) on the structural damping of the composites were further performed. Finally, the optimal layout was obtained as a result of the theoretical analysis. The experimental and theoretical results in the paper will be valuable to the composite structural design with high requirements both to the mechanical and damping performance.