Predicting the mechanical behaviour of highly particle-filled polymer composites using the nonlinear finite element method

Highly particle-filled polymer composites (HPFPCs) usually consist of stiff crystal particles, polymeric binder/matrix and the interfaces between the particles and the matrix. Unlike normal particle-filled composites, the particle filled ratio of HPFPCs can reach around 90% to 95% by weight, which makes it difficult to study the mechanical properties of HPFPCs by traditional schemes. To explore the mechanical performance of HPFPCs thoroughly, the influences of strain rate, temperature, interface properties (interface strength and fracture energy), and micro-structure (particle volume fraction (PVF) and particle distribution) on the fracture mechanisms have been systematically investigated using the nonlinear finite element method. A micro numerical scheme has been developed, including the development of mechanical constitutive models for each constituent of HPFPCs, and the generation of the micro-structural model with the PVF of over 90% using a Voronoi-modified method. The multiple failure events have been reproduced including the visco-elastic deformation, the fracture of the matrix, and interfacial debonding dominating the crack mode. The predicted results are in good agreement with the available experimental measurements and other numerical simulation results. This work provides a robust numerical tool to analyse the micro-mechanical behaviour of HPFPCs.