Hysteretic behaviour of uniaxially thermoformed auxetic foams under 3-point bending low-frequency vibration

Abstract The work describes experiments and models related to auxetic (negative Poisson’s ratio) foams subjected low-frequency variable amplitude 3-point bending loading. A custom vibration test rig is designed used perform the dynamic of PU foam beams within range (1–20 Hz) 5 different displacement amplitudes. tested in this are manufactured using a simplified relatively low-cost uniaxially thermoforming compression technique, which leads production with transverse isotropic characteristics. Auxetic beam samples two cutting orientations ratios r c (20–80%) compared, also use theoretical Euler–Bernoulli-based finite element models. modulus increases , ranging between 0.5 MPa, while loss factor marginally affected by ratio, overall values 0.2 0.3. has noticeable amplitude-dependent stiffness factors, but slightly decreases frequency. 20–40% larger than quasi-static one, static factors quite close. modified Bouc–Wen model further developed capture frequency-dependent properties conventional volumetric ratios. shows good agreement experimental results.