  We propose an efficient method to build a simple discrete element model (DEM)
that accurately simulates the oscillation of a continuum beam. The DEM is based
on the Timoshenko beam theory of slender cylindrical members and their
corresponding wave dynamics in assembly. This physics-informed DEM accounts for
multiple vibration modes of the constituting beam elements in wide frequency
ranges. We construct various DEMs mimicking cylinder chains and compare their
wave dynamics with those measured in experiments to validate the proposed
method. Furthermore, we construct a graded woodpile chain of slender cylinders.
We experimentally and numerically investigate the frequency bandgaps of the
system and demonstrate the possibility of constructing a wide bandgap by
consecutively superposing multiple stop bands generated from cylinders of
various lengths. This system is highly efficient in blocking propagating waves
by leveraging the vibration isolation effect stemming from the local resonance
of the cylinders. The proposed DEM method can be useful for investigating and
designing complex vibration systems in an efficient and accurate manner.
Moreover, the design approach of manipulating the frequency bandgap can be
exploited for developing vibration filters and impact mitigation devices.
