Compressive properties of biologically inspired anisotropic TPU/CB composites for mechanical sensor

Abstract Conventional thermoplastic polyurethane/carbon black (TPU/CB) composites suffer from uncontrollable elasticity modulus and recoverability due to the randomness of the internal structure. Inspired by biological materials that enhance mechanical properties through regularly arranged microstructures, biomimetic materials with axially and radially aligned microstructures are prepared using bidirectional freezing technology. It is found that in the axial direction, the performance of structures is almost unaffected by structural design perpendicular to the load direction. It confirms that load transfer primarily depends on the microstructure in the load application plane. In the radial direction, compared to the disordered structure, the biomimetic structure shows a decrease in the elastic modulus of 38.9% and an increase in peak stress of 25.4%, respectively. Combining experimental and simulation analyses, the enhancement mechanism of the material is attributed to the regular distribution of microstructures. This regular distribution reduces internal self‐constriction and prevents stress concentration. It also optimizes stress distribution, improves deformation coordination, and reduces yielding. Additionally, it enhances the recovery capability and repeatability of the material. It can be concluded that the radial compressive properties of biomimetic structures compared with those of disordered structures meet the requirements for the design of compressive mechanical sensors. Highlights Biaxial freeze‐casting microstructural design of TPU/CB composites Comparing compressive properties of biomimetic and disordered materials. Analyze the compression performance of both axial and radial directions. Combine experiments and simulations to analyze the deformation mechanism. The material's radial compression performance is more suitable for sensors.