An experimental investigation into the mechanical behaviors of helical composite springs

In this study, four different types of helical composite springs were made of structures including unidirectional laminates (AU), rubber core unidirectional laminates (UR), unidirectional laminates with a braided outer layer (BU), and rubber core unidirectional laminates with a braided outer layer (BUR), respectively. It aims to investigate the effects of rubber core and braided outer layer on the mechanical properties of the aforementioned four helical springs. According to the experimental results, the helical composite spring with a rubber core can increase its failure load in compression by about 12%; while the spring with a braided outer layer can not only increase its failure load in compression by about 18%, but also improve the spring constant by approximately 16%. The helical spring with a BUR structure has the highest mechanical properties among those considered herein, its failure load in compression approximately equals 336.2 kgf, and the spring constant is almost 16.27 kgf/mm.