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A Novel Architectured Polymer Composite for Near Isotropic Characteristics and Improved Combined Stiffness—Damping Properties



A novel micro-architecture is proposed to design multifunctional composite with simultaneous stiffness and damping capabilities. The micro-architecture utilizes the hexagonal symmetry in order to manifest in-plane isotropy in the properties. The micro-architectured composite is made of circular gear and triangular shaped stiff material and a layer of viscoelastic material in between them. The gear and triangular shaped building blocks is designed to utilize the interlocking mechanism for them to transfer load through the interlock under tensile load. The combination of the stiff and the viscoelastic material in the composite yields to both high-stiffness and highdamping, which otherwise are competing in engineering materials. Numerical experiments are performed in order to characterize the design and quantify the performance parameters of the micro-architectured composite using PMMA as the stiff materials and PU as the viscoelastic materials. Quasi-static tensile behavior and damping performance under low frequency load is predicted using finite element analysis. The thickness of the PU layer is varied to investigate the effect of PU volume fraction. The simulation results show that with approximately 7 percent volume fraction of PU the composite retains 55 percent stiffness of PMMA. With the increase in PU volume fraction (layer thickness), the damping of the composite increases and the stiffness decreases. The composite achieves 10 and 50 percent damping of PU with only 7 and 30 volume percent of PU, at 10 Hz loading frequency. The combined performance (i.e. multiplication of stiffness and damping) is found to be close to Wang-Lakes line, which is notable for a polymer-polymer composite.


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