The skeleton of Euplectella aspergillum as foundation for the development of novel composite aerospace structures

Biological materials have long attracted the attention of researchers in different science fields owing to their unique structure and mechanical performance. This paper presents some of the key design strategies, adopted by the hexactinellid sponge E. aspergillum. The laminated configuration of the spicules and silica cement, the periodic lattice arrangement and the fusion strategies play a prominent role in enhancing the structural performance of the skeleton. It is established that the overlapping pattern of the spicules, forming the main framework, is not consistent in all sections of the lattice. Several toughening mechanisms which significantly contribute to the damage tolerance capabilities of the skeleton are identified and discussed. In addition, a novel lattice, inspired by the skeleton of E. aspergillum, is introduced. The performed determinacy analysis of the finite and infinite structures indicates that the lattice experiences pre-stressed behaviour characterised with stiffening the internal mechanisms by the states of self-stress.