Characterization and Model Validation for Large Format Chopped Fiber, Foamed, Composite Structures Made from Recycled...

Area of Science:

• Materials Science
• Composite Materials
• Polymer Engineering

Background:

• Large format foamed core composite structures, like crossties, are made from recycled High-Density Polyethylene (HDPE) and Glass Filled Polypropylene (GFPP).
• Predicting performance is challenging due to microstructural variations affecting macroscopic responses.
• Structures feature a dense outer shell and a closed-cell foamed core.

Purpose of the Study:

• To predict the material performance of foamed core composite structures using only constitutive properties.
• To establish a mathematical correlation between microstructural variations and macroscopic responses.
• To validate micromechanics and Finite Element Analysis (FEA) models against experimental data.

Main Methods:

• Micromechanics models analyzed non-linear shell and foamed core properties.
• Modified Rule of Mixtures predicted reference stress for shell and core.
• FEA models, initially linear then non-linear (Ramberg-Osgood), simulated four-point bend tests.

Main Results:

• Linear analysis showed no deflection variation for isotropic/transversely isotropic models.
• Non-linear FEA model predicted full four-point bend test behavior.
• FEA model results deviated by 2.45 kN, compared to experimental variation of 3.58 kN.

Conclusions:

• The non-linear FEA model effectively predicts the behavior of foamed core composite structures.
• Constitutive properties can be used to accurately forecast material performance.
• The study validates the use of micromechanics and FEA for recycled composite material analysis.