A Hierarchical Molecular Dynamics and Peridynamics Approach to study Fracture of Green Nano Fibrous Network

Poly(lactic acid) (PLA) nanofibrous networks possess unique and versatile properties that make them appealing for various applications in engineering and science, such as tissue engineering, drug delivery, and filtration. These properties include biodegradability, high strength, tunable mechanical properties, high surface-to-volume ratio, and surface functionality. However, the intricate nature of the nanofibrous network arising from structural complexity, multiscale features, and variability in material properties, presents a challenge for prediction of mechanical behavior. An appropriate modelling can provide information on the effect of different material and configurational parameters on their physical characteristics. Through a multi-scale nano-macro modelling, we can preserve the accuracy of atomistic modelling while benefiting from the efficiency of continuum description. In the present work, a multi-scale approach is conducted that bridges atomistic simulation to macro scale descriptions to investigate the fracture properties of a three-dimensional nanofibrous network. At the atomistic scale, all-atom molecular dynamics (MD) simulations are performed on individual untreated and silver-doped poly(lactic acid) nanofibres to determine the critical strain, elastic modulus, shear modulus and yield stress. Hierarchically, at the macro scale, peridynamics (PD) is implemented, which is suitable for damage prediction in dynamic fracture analysis as it incorporates integral equations. The parameters obtained from MD are implemented in PD to study crack propagation and determine fracture toughness in a randomly oriented as well as aligned fibrous network. The determined fracture toughness of the original and silver-doped poly(lactic acid) nanofibrous network agrees well with the available experiments, indicating the effectiveness of the proposed approach. The current research paves the way for the development of stronger and more durable eco-friendly nanofibrous networks with optimized performance.