Experimental study on the dynamic properties of rigid polyurethane foam in stress-controlled cyclic uniaxial tests

Frequent major earthquakes in Japan necessitate earthquake-resistant infrastructure. The dynamic deformation characteristics of rigid polyurethane foam, used as a lightweight embankment material, is examined in this study. The effect of the initial static stress on the shear modulus of single-layer samples was small, while the shear modulus of two-layer samples increased with increasing initial static stress. The damping ratio of single-layer samples converged to 4-5%, but decreased with increasing initial static stress up to 30 kPa in two-layer samples before increasing above 40 kPa. Results from cyclic uniaxial and triaxial tests were compared. The dynamic properties depended on restriction conditions and the deformation direction.