Session: 03-05-02: Integrated Computational Materials Engineering

Paper Number: 121572

121572 - Integration of Nanoscale and Microscale Analysis for Process Modeling of Toray 3900 Epoxy Resin Using Icme 

Thermosetting polymer matrix composites (PMCs) are extensively used for aerospace structural applications due to their low density, high specific strength, and stiffness. Despite their popularity, predicting the polymer matrix composite (PMC) thermo-mechanical responses as a function of processing parameters is challenging due to their complex multiscale nature. The process-induced uncertainties have a significant impact on their thermo-mechanical properties. Multiscale computational process modeling can provide valuable insight into physical phenomena that influence the composite thermo-mechanical response and establish a processing-microstructure-property correlation.

In this study, an integrated multiscale process modeling framework to predict process-induced residual stress generation in PMCs and quantify its effect on their thermo-mechanical response is presented. Computational modeling techniques at two length scales are explored: nanoscale and microscale. At the nanoscale, molecular dynamics (MD) simulations are carried out to evaluate the chemical and thermo-mechanical properties of a toughened epoxy system, Toray 3900 (T3900). Using the Reactive Interface Force Field (IFF-R), the properties are computed for a range of crosslinking densities (from uncrosslinked state to fully-crosslinked state) and validated against experimental data. The predicted properties include mass density, post-gelation volumetric shrinkage, elastic constants such as bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, yield strength, glass transition temperature, and coefficient of thermal expansion. At the microscale, finite element-based (FE) process modeling simulations are carried out on representative volume elements (RVEs) of composite microstructures comprising IM7 carbon fibers embedded in the T3900 epoxy matrix. Process modeling analyses, informed by the MD data, are carried out to model the evolution of the thermomechanical properties of the T3900 and predict the residual stress generation during composite manufacturing in ABAQUS through user-written subroutines. Subsequent virtual mechanical tests are carried out on the manufactured RVEs subjected to several loading conditions to evaluate the influence of process-induced residual stress on the composite mechanical response. The results from this work demonstrate that process-induced residual stresses have a significant impact on the composite strength in transverse tension, in-plane shear, and out-of-plane shear and must therefore, be accounted for during design and optimization of composites.

This work presents an integrated approach, which is informed by accurate and comprehensive material property data, that can be used to design and optimize composite structures for specific engineering applications and provide refined processing parameters for superior composite properties at reduced composite manufacturing energy and cost.

Presenting Author: Sagar Patil Michigan Technological University

Presenting Author Biography: Dr. Sagar Patil received his Ph.D. from Michigan Technological University in Mechanical Engineering- Engineering Mechanics under the guidance of Dr. Gregory Odegard. His research focuses on molecular modeling of high-performance polymers. His technical expertise includes Molecular Dynamics, DFT, micromechanics, and FEM. He specializes in modeling complex chemistries of multi-functional epoxies such as Toray 3900, BMI, Cyanate Esters, PBZ, Polyimides, PEEK, and Carbon nanotubes. He is currently working as a postdoctoral scholar in Dr. Greg Odegard's CMMR Lab at Michigan Technological University. He has Master's and Bachelor's degrees in Mechanical Engineering from India.