Direct and Indirect Measurement of Complex Poisson's Ratio - Direct Measurement in Compression

Here, the axial and transverse strains were measured locally with strain gauges (K-CXY3-0060-3-350-O, HBK, Darmstadt, Germany) on cylindric polymethyl methacrylate (PMMA, EH-Design, Wörrstadt, Germany) samples with a diameter of d = 30 mm. Dynamic mechanical analysis (DMA) was performed with the piezoelectric actuator (8P-035.20P, Physik Instrumente, Karlsruhe, Germany) driven by the high power amplifier (E-482, Physik Instrumente, Karlsruhe, Germany).

Small strain amplitudes excitation in the frequency range from 0.1 Hz to 1000 Hz are performed. To ensure the oscillation around a strain amplitude, a static preload is applied by a universal testing machine (RM50, Schenk, Germany). Transversal and axial strain is then measured on the PMMA sample with strain gauges in compression mode.