Development of composite springs using 4D printing method

Composite springs have been used in many engineering applications, particularly in the transportation industry. This is due to their light weight, good stiffness, good strength, good corrosion and fatigue resistances. Normally special molds need to be prepared in the manufacturing of these springs. The molds have curvatures which fit into the shape of the final product. Recently the concept of 4D printing of composites was introduced. This concept is a combination of 3D printing together with the reconfiguration of the part upon the activation of some mechanism such as heat, light, or the absorption of moisture. This concept allows the ability to make structures of complex shapes without the need to have complex molds. Layers of composites can be laid on a flat mold. Upon curing, the layers reconfigure into curved structures. As such, curved composite structures can be made using only flat molds. The mechanism for this reconfiguration depends on the anisotropic nature of layered composite materials. This paper presents the fundamental study, as part of a larger project intended to use the concept of 4D printing to develop complex composite structures without the need for complex curved molds. The fundamental study examines the mechanical characteristics of curved composite beams made by 4D printing.