Mechanically self-adaptable materials, a novel bio-inspired pathway for overcoming fatigue failure.*

Classical approach of developing new engineering materials rely on enhancing their properties. Unexpected crack growth initiating at stress concentrations under fatigue loading leads to premature failures. Interestingly, many materials in nature can dynamically change their properties to conform with different loading conditions. Bone is an excellent example for this capability. Building upon our previous work demonstrating proportional mineral deposition as a function of a stress using piezoelectric scaffold [1], we report a bioinspired pathway for next generation materials with improved fatigue resistance. We found that pre-notched piezoelectric samples submerged in a simulated body fluid showed their ability to adapt in response to applied fatigue loading without external intervention. As piezoelectric materials generate charges proportional to the applied stress, stress-concentration leads to higher deposition rates resulting in lower overall stress at crack tip. Accordingly, significant enhancement was observed in the fatigue life. The proposed pathway can help increase the components’ reliability and reduce material overdesign.

[1] Orrego, Santiago, et al. "Bioinspired Materials with Self‐Adaptable Mechanical Properties." Advanced Materials 32.21 (2020): 1906970.