# Research on Modeling for the Flow–Compaction Process of Thermosetting Epoxy Resin-Based Composites

## TL;DR

This paper presents a simulation model to predict porosity changes in thermosetting epoxy composites during the curing process.

## Contribution

A multi-physics coupling model integrated into ABAQUS to simulate flow–compaction behavior and predict porosity evolution.

## Key findings

- Porosity at L-shaped fillets is higher due to insufficient shear slip capacity.
- Fiber bed stiffness and inter-ply friction significantly affect porosity changes.
- The simulation model was validated with experimental porosity measurements.

## Abstract

Addressing the issue of porosity evolution during the curing process of thermosetting epoxy resin-based composites, a simulation model has been developed to describe the flow–compaction behavior of the composites aiming to predict changes in porosity throughout the curing process. Initially, a multi-physics coupling model encompassing sub-models for thermo-chemical, fiber bed compression, void compression, and percolation flow was established. This model accurately describes the changes in porosity within the composites during the flow–compaction process. The UMAT subroutine of the ABAQUS finite element analysis software was utilized to integrate these sub-models into the software. The validity of the simulation model was verified through corresponding experimental porosity measurements. The research further indicates that the porosity at the fillet of L-shaped composite components is higher than that in flat areas due to insufficient shear slip capacity. The results show that the porosity of the rounded corners of the L-shaped composite members is higher than that of the flat plate region due to the lack of shear slip capacity, and the fiber bed stiffness and inter-ply friction coefficient play an important role in the change in porosity.