Flexural response of concurrently 3D printed sandwich composite

TL;DR

This study investigates the flexural behavior of 3D printed sandwich composites with syntactic foam cores reinforced with glass microballoons, demonstrating improved mechanical properties and validating experimental results with theoretical models.

Contribution

It introduces a novel method of 3D printing sandwich composites with GMB-reinforced HDPE cores and characterizes their flexural performance.

Findings

GMB addition enhances specific modulus and strength.

Sandwich composites outperform core materials in flexural tests.

Experimental results align well with theoretical predictions.

Abstract

Among many lightweight materials used in marine applications, sandwich structures with syntactic foam core are promising because of lower water uptake in foam core amid face-sheets damage. HDPE (high-density polyethylene) filament is used to 3D print sandwich skin, and glass microballoon (GMB) reinforced HDPE syntactic foam filaments are used for the core. The optimized parameters are used to prepare blends of 20, 40, and 60 volume % of GMB in HDPE. These foamed blends are extruded in filament form to be subsequently used in commercially available fused filament fabrication (FFF) based 3D printers. The defect-free syntactic foam core sandwich composites are 3D printed concurrently for characterizing their flexural behavior. The printed HDPE, foam cores, and sandwiches are tested under three-point bending mode. The addition of GMB increases both specific modulus and strength in sandwich composites and is highest for the sandwich having a core with 60 volume % of GMB. The flexural strength, fracture strength, and strain of foam core sandwiches registered superior response than their respective cores. The experimental results are found in good agreement compared with theoretical predictions. Finally, the failure mode of the printed sandwich is also discussed.