Flexure-after-impact behaviors of green composite sandwich beams with natural fiber facesheets and balsa cores

Composite sandwich structures composed of artificial materials are widely used. However, manufacturing artificial materials requires extensive energy and significantly impact our environment. Therefore, there is a growing focus on manufacturing composites using natural materials. This study used flax fabric, cotton fabric, glass fiber fabric, and polylactic acid (PLA) to fabricate the facesheets of sandwich beams, with balsa panels used as the cores. Tensile, flexure, tensile-after-impact (TAI), and flexure-after-impact (FAI) tests were conducted on the constituent materials and the sandwich beams. As expected, glass fiber reinforced PLA (GFRP) exhibited the highest tensile, flexural, and TAI properties compared to flax fiber reinforced PLA (FFRP) and cotton fiber reinforced PLA (CoFRP) and contributed to the highest FAI strengths in the sandwich beams using GFRP facesheets. It was also observed that a stiffer facesheet resulted in more core crushing in its sandwich beams when subjected to FAI tests, while a weaker facesheet led to more debonding in its sandwich beams. Since sustainable natural materials have been attracting research interest and are used in various areas, this work contributes to using natural composite materials and sustainable development.