  The rise of soft materials and additive manufacturing has provided the
feasibility of developing elastomer lattices for various engineering
applications. Although earlier attempts have been made to manufacture and test
the elastomer lattices, a comprehensive understanding of their fracture
behaviour has remained elusive. Inspired by the soft foams in mussel plaque
core, the present study introduces the concept of soft, ductile, and tough
elastomer lattices. Uniaxial and planar tension tests were conducted, and
numerical models were developed to facilitate data interpretation. The
applicability of planar tension for measuring the fracture energy of elastomer
lattices was confirmed through tensile tests using samples with various crack
lengths and double-peeling tests. In addition, the fracture energy of the
elastomer lattices was sensitive to volume fraction but insensitive to initial
crack length, thickness, and height. Notably, two distinct failure modes, truss
failure and joint failure, were correlated with volume fraction. The specimens
that failed at the transition between these two failure modes achieve a higher
fracture energy. This study provides new insights to the materials science
community and provides a foundation for the development of lightweight,
damage-tolerant, and high-performance metamaterials.
