| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 107 === In this study, the hard and soft compounded, additive manufacturing is used to investigate the mechanical properties of composite materials. We use PolyJet method to print soft and hard material as the composite structural beam. First, the soft material with viscoelastic property used the tensile test and stress relaxation to obtain the parameters, and then using the parameters import the finite element analysis to establish Prony series, using dynamic experiments to impact the composite-material specimen, the equivalent elastic constant is measured by inversely calculation from the first natural mode, according to the Euler–Bernoulli beam theory. Recalculating by the finite element analysis to simulate the natural frequency and use dynamic impact simulation, the accuracy of the experiment measurement was verified in the dynamic properties of the viscoelastic material.
Viscoelastic materials at low frequency has a lower rigidity because of vibrating absorption. Contrary, the viscoelasticity at high frequency has a higher rigidity. This study also uses the differently compounded models to verify the dynamic characteristic of material property, The difference between symmetric and asymmetric heterogeneous materials, and different thickness ratios, respectively, is also discussed on the applicability material properties in accurately of structural natural frequencies.
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