Laboratory Study of Polypropylene-based Honeycomb Core for Sandwich Composites

Abstract

Nowadays, a structure of sandwich composites can be reinforced by with hybrid materials such as polypropylene core. Due to its high strength properties, the polypropylene is widely used in various fields of science, technology and engineering including aerospace applications. This research studies the well-known hybrid composites of a carbon fiber (CF) and glass fiber (GF) to evaluate the mechanical properties under the presence of sandwich composites reinforced with such fibers. The different curing-pressure values of each material workpiece have been investigated to determine the curing pressure, resulting in the superior performances and properties. The specimens are moulded by the hand lay-up (i.e., cloth laying angle) of the carbon fiber. By changing direction, the specimens are determined the greatest load-bearing direction based on the bending test. According to the ASTM standard on the strength determination, it is found that when the curing pressure increases, the flexural stress increases. By placing the material orientation in the order (i.e., [CF90 / CF0 / GF0 / Core / GF0 / CF0 / GF0]) provides the highest strength. When the strain reaches its maximum value, the specimens actually fracture. The fracture propagation is generally followed the fiber orientation of the fabric. The experimental results are observed that the lower curing pressure the thicker of the work piece and the fiber volume fraction decreases. The obtained results show that changes in the curing pressure and laying angle significantly affect the mechanical properties of the sandwich composites