Particle-scale insight into transitional behaviour of gap-graded materials – small-strain stiffness and frequency responseMasahide Otsubo, Troyee Tanu Dutta, Manushak Durgalian, Reiko Kuwano and Catherine O'SullivanE3S Web Conf., 92 (2019) 14006DOI: https://doi.org/10.1051/e3sconf/20199214006