4D printing of composites
3D printingis a widely popular technique for the additive manufacturing of complex structures. 4D printing method combines 3D printing of a flat stack of materials with the reconfiguration of the flat structure into a structure with complex geometry, upon some activation mechanism such as heat, light, or the absorption of liquid such as water [1, 2]. Both 3D printing and 4D printing usually use soft materials that may not possess high strength and high stiffness. This type of 4D printing is termed as “Regular 4D printing” in this work. 4D printing of composites (abbreviated as 4DPC) utilizes the concept of Regular 4D printing but 4DPC uses light weight, high strength, high stiffness composite materials that have been used to make engineering structures such as parts of aircrafts or automobiles. The method of manufacturing structures using 4DPC is via an Automated Fiber Placement (AFP) machine, where a robotic arm is used to deposit layers of the composite on a mandrel. The 4DPC method has been used to make complex composite structures and this has been reported in . Composite leaf springs with high stiffness and strength have also been made using this method . Composite layers were deposited onto a flat mold. Upon the activation of heat (curing of the composites), the flat layers become curved and this provides the shape for the leaf spring. The governing principle for the reconfiguration depends on the anisotropic nature of the composite lay up.
The presentation will cover developments of 4DPC from the governing principles to the few applications to date. The governing principles involve the use of laminate theory to determine the change in shape of laminates made of different types of lay up sequences. The effect of temperature and moisture will be discussed. Potential applications include the development of leaf springs, coil springs, the use of the technology for the manufacturing of aircraft wing structure that facilitate morphing, and the development of wood facades that change their configuration upon the absorption of moisture.
References: . S. Tibbits. The emergence of 4D printing”, TED conference, 2013. . F. Momeni, S. Mehdi, N. Hasani, X. Liu, and J. Ni. “A review of 4D printing”, Material and Design, 122, 2017, 42079. . S. Hoa. “Factors affecting the properties of composites made by 4D printing (moldless composite manufacturing), Advanced Manufacturing: Polymers & Composites Science, Vol. 3, No. 3, 2017, 101-109. . S. Hoa. “Development of composite springs using 4D printing method”, Composite Structures, 210, 2019, 869-876.
About the Speaker
Dr. Suong Van Hoa is a professor in the Department of Mechanical, Industrial, and Aerospace Engineering at Concordia University in Montreal, Quebec, Canada. He has worked on many industrially related composite projects with companies such as Bell Helicopter Textron Canada Ltd., Bombardier Aerospace, Pratt & Whitney Canada etc. He has published more than 500 articles in scientific journals and conferences. He is author of the text book “Principle of the manufacturing of composites” published by Destech, which is now in second edition. He conceived the idea of 4D printing of composites since 2016 and he has worked vigorously on its development. He is fellows of the Canadian Academy of Engineering, the American Society of Mechanical Engineers, the Canadian Society for Mechanical Engineering, the Engineering Institute of Canada, and of the American Society for Composites.