Rapid development in the field of additive manufacturing, evidenced, in part, by the proliferation of low cost 3D printing, has accelerated the prototyping and design evaluation stages of the product development cycle. 3D printed structures have shown variations in their material properties as a function of the printing orientation. Moreover, thermoplastic materials which are often used as filament materials for 3D printing are known to have dependency on temperature, frequency and strain rate. Hence, the aim of this research is to estimate the variations in the complex modulus of the printed materials as a function of printing direction. This will allow an estimation of the variation in the vibration characteristics (natural frequencies, damping) of the printed structures as a function of printing direction. To this end, PLA beams were printed in four different orientations. A dynamic mechanical analyzer was used to measure mechanical properties of the printed beams. By using a curve fit method, the frequency and temperature dependent complex modulus is estimated. These complex moduli are used for estimating the eigenvalues of a non-dimensional beam. The observed variability in the vibration behavior as a function of the printing orientation is summarized here.

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