Effects of Average Number of Platelets Through the Thickness and Platelet Width on the Mechanical Properties of Discontinuous Fiber Composites

TL;DR

This paper investigates how the number of platelets through the thickness and their width influence the tensile properties of Discontinuous Fiber Composites, using experimental and numerical methods to predict material behavior and variability.

Contribution

It introduces a novel mesostructure generation algorithm and finite element modeling approach to accurately predict tensile properties and their variability in DFCs based on platelet configurations.

Findings

Tensile modulus and strength increase with more platelets through the thickness.

Asymptotic limits of 45 layers for narrow and 27 for square platelets were identified.

Accurate mesostructure simulations can predict both average properties and variability.

Abstract

In this study, we experimentally and numerically investigate the evolution of the tensile material properties of Discontinuous Fiber Composites (DFCs) with an increasing average number of platelets through the thickness for two different platelet widths. The results show that both the number of platelets and the platelet width have significant effects on the tensile modulus and strength. We find that not only the average mechanical properties but also their coefficients of variation change according to the different DFC mesostructures. To understand the relationship between material morphology at the mesoscale and corresponding material properties, we developed a random platelet mesostructure generation algorithm combined with explicit finite element models. Leveraging the computational tools, we find that moduli and strength increase with increasing average number of platelets through the thickness. The increasing trend continues until reaching an asymptotic limit at about 45 layers through the thickness for the narrow platelets and 27 layers for the square platelets. In the study, we address the importance of having accurate simulations of the mesostructure to match not only the average modulus and strength but also their associated coefficients of variation. We show that it is possible to accurately predict the tensile material properties of DFCs, including their B-basis design values. This is a quintessential condition for the adoption of DFCs in structural applications.