FLYWHEEL : Jurnal Teknik Mesin Untirta
Vol 12, No 2 (2026)

EFFECT OF ASYMMETRIC CARBON FIBER SKIN LAYER DISTRIBUTION ON THE FLEXURAL STRENGTH OF POLYPROPYLENE HONEYCOMB SANDWICH COMPOSITES

Muhammad Nauval Althaaf Lovrien (Universitas Muhammadiyah Surakarta)
Muhammad Alfatih Hendrawan (Universitas Muhammadiyah Surakarta)



Article Info

Publish Date
13 Jul 2026

Abstract

Advances in energy-efficient vehicle technology require lightweight materials that maintain high structural strength. One developed alternative is a polypropylene honeycomb-based sandwich composite structure reinforced with carbon fiber for monocoque chassis applications. This study aims to analyze the effect of varying the number of carbon fiber layers in the top and bottom skins on bending strength and post-test damage characteristics. Specimens were fabricated using the vacuum infusion method at a pressure of -0.8 bar, employing a polypropylene honeycomb core, 3K twill carbon fiber, and an epoxy matrix. Bending tests were conducted using the three-point bending method in accordance with ASTM D790 on three configuration variations: 5-3, 4-4, and 3-5 (top skin–bottom skin). The results showed that the configuration with 5 layers on the top skin and 3 layers on the bottom skin yielded the highest flexural strength of 15.456 MPa, followed by the 4-4 configuration at 12.469 MPa and the 3-5 configuration at 11.654 MPa. Macroscopic analysis revealed failure mechanisms including bending deformation, delamination, core crushing, matrix cracking, lower skin cracking, and fiber pull-out. It is concluded that increasing carbon fiber layers in the top skin significantly enhances flexural strength and reduces damage to the sandwich composite structure.

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Journal Info

Abbrev

jwl

Publisher

Subject

Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Control & Systems Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Transportation

Description

The journal publishes original and (mini)review articles covering the concepts of materials science, mechanics, kinematics, thermodynamics, energy and environment, mechatronics and robotics, fluid mechanics, tribology, cybernetics, industrial engineering and structural analysis. The journal follows ...