Compressive behaviour of anisotropic mycelium-based composites

Abstract

Mycelium based composites (MBC) exhibit many properties that make them promising alternatives for less sustainable materials. However, there is no unified approach to their testing. We hypothesise that the two-phase particulate composite model and use of ASTM D1037 could provide a basis for systematisation. An experimental series of MBC were produced using four substrate particle sizes and subjected to compression testing. We report on their effect over Young’s modulus and ultimate strength. We extend the study by investigating three anisotropic substrate designs through orientated fibre placement as a strategy for modifying compressive behaviour. We find that the two-phase particulate model is appropriate for describing the mechanical behaviour of MBC and that mechanical behaviour can be modified through anisotropic designs using orientated fibres. We also confirm that fibre orientation and particle size are significant parameters in determining ultimate strength.

Growth and Mechanical Characterization of Mycelium-Based Composites towards Future Bioremediation and Food Production in the Material Manufacturing Cycle

“…For cylindrical specimens, the shrinkage has been estimated to be around 17% in height (vertical shrinkage) and around 10% in diameter (horizontal shrinkage) [ 9 ]. For rectangular specimens, shrinkages of 5.56% horizontally and 2.78% vertically have also been observed [ 42 ].…”

“…Various research articles studied the mechanical properties of mycelium-based materials, which have been described by a two-phase particulate model with the mycelium as the matrix and substrate as the dispersed phase [ 7 , 8 , 9 , 10 , 11 , 42 ]. The differences in the production, dimensions, description, and testing procedures of such bio-composite materials make data comparison between studies difficult, as they severely impact their mechanical behavior [ 42 ]. The mechanical behavior of mycelium-based materials highly depends on the anisotropic substrate matrix.…”

“…The mechanical behavior of mycelium-based materials highly depends on the anisotropic substrate matrix. A study recently looked at the effect of fiber orientation within the substrate on the compressive behavior of mycelium-based materials [ 42 ]. The study found that adding fibers oriented in the direction of loading increased Young’s modulus.…”

“…Due to the novelty of the research field of mycelium-based composites, many research questions still need to be addressed before their implementation in permanent architectural projects [ 5 ]. For instance, more studies should explore particle shapes, composition, and distributions due to their significant influence on mechanical properties [ 42 ]. The substrate particle size for an optimal balance between mycelial growth and mechanical performances is still subject to research.…”

“…In their study, they compared five different substrate particle sizes with varying aspect ratios (2, 5, or 8), sizes (2.5, 5, or 10 mm), and diameters (0.5, 1, or 2 mm). In another study, materials made from medium particles (0.75–3.0 mm) led to higher density, Young’s modulus, and ultimate strength than others made from smaller (0.5–1.0 mm), larger (4.0–12.0 mm), or more diverse (0.5–12.0 mm) particles [ 42 ]. This study also showed that higher density did not increase compressive performance in all cases.…”