Structure Optimisation_Cancellous Bone Tissues: High Strength to Weight ratio
An interesting example of lightweight, redundant and highly-differentiated structures in nature, which drive the biomimetic research in order to derive morphological and performance properties that will inform the design process of our project, is found in bone tissues, especially bird skulls tissues.
Skulls in general are extraordinary impact-resistant structures and extremely light at the same time as they protect the most important organs of an animal body and this performance and physical property can be applied in structure or architecture design. ‘Lightweight’ can be defined by the ratio of the active or life load is carried over its dead load, being the longer the better; in other words, the more loads a structure can carry with least structural inherent weight, the better. Most of the bone tissues, especially in larger song bird skulls, are build up from non-directional spongiosa cells, which mean they are configured by pneumatized cells that allow air voids between solid material areas reducing the overall weight of the structure without affecting its strength. The resultant configuration of the system is a highly strong and highly lightweight material system where the main structural performance relies on different cell components that are integrated into a major pneumatized system and it is not focalized just on the outer layer. In fact, the bone tissues of song bird skulls are formed by very thin external lamellas that enclose a sponge cancellous tissue.
In the case of small song bird’s skulls such as Carrion Crows and Magpies, the configuration is based on elongated differentiated cells in a single or two-story air-package area. This morphological configuration provides an acoustic function distributing air at the inner layer but also determines a light and strong structure. The regional cells then are distributed in a manner that can provide a multi-function performance.In regards to material properties, bone’s tensile strain (0.011 N/m2) and compression strain (0.015 N/m2) is quite similar to a wide range of synthetic resins as it is shown on the Resin’s structural performance chapter, relating the material investigation to Biomimetic research in terms of generating achieving a similar structural capacity of bones both in a material level and a morphological level at the same time.
Anisotropism, heterogeneity and Redundancy_ Bird Skull tissues
Digital representation of a biomimetic double-layered surface