Ultra Lighweight shape Adaptable Composites for Aerospace and Biomedical Applications

Fiber reinforced polymers (FRP) possess outstanding specific stiffness and strength and are therefore pre-destined for applications in high performance lightweight structures. The combination of anisotropic properties and multilayer arrangement embraces a vast design space, which allows realizing amazing structural features such as concurrently fulfilling contradictory requirement of extreme deformability in load-carrying structural systems. The integration of FRPs elements into mechanical metamaterials is further expanding the potential of composite materials for multi-functional lightweight applications, by adding additional geometrical parameters and tunability of the repeating unit cell.

The talk is introducing and discussing the potential of novel metamaterials architectures for shape adaptation. A promising concept is relying on FRP shell metastructures consisting of a thin FRP-frame and a pre-stretched soft polymer membrane. The instability of the initially flat component is inducing a rich multi-stable behavior, being a first step towards the realization of programmable structures, which can morph to multiple 3D shapes from an initial flat configuration upon an external stimulus.

The second part of the talk is introducing and discussing the mechanical behavior and the potential of very thin composite shells made from continuously fiber reinforced Polyether ether ketone (PEEK). Those composite materials are capable to withstand large bending curvatures without failure and are therefore pre-destined for applications, which require high degree of deformability for shape adaptation and deployment purposes, but also ultra-lightweight design solutions combined with sufficient rigidity to ensure functionality of the deployed system. The talk will address the investigations carried-out at ETH to characterize and describe the influence of the non-linear mechanical response of the carbon fiber, of the matrix type and of the shell thickness on the bending failure behavior of the composite shell, also discussing the applicability of thin fiber reinforced PEEK shells in selected biomedical and space systems.