4D printing mechanics, modeling, and advanced engineering applications

Four-dimensional (4D)-printed smart materials and structures are engineered, complex-shaped mechanisms that respond to external stimuli according to what was programmed during the printing stage. In the application of 4D printing, given a selected material, a printing approach, and a programming method, the final step for establishing 4D printing is modeling the original structure and predicting its shape- and property-changing behavior. Indeed, simulating the smart material dynamics requires multiphysics simulations. The mechanical calculation or finite-element analysis (FEA) needs to be combined with extra physical field such as thermal, electrical, and magnetic, depending on the stimuli mechanism. Currently, there are a few tools available using analytical and numerical approaches to find the target design on this topic. New structural design and advanced simulation and modeling tools can further advance 4D printing. Therefore, the research efforts and progress in 4D-printed structures and systems toward a strategic top-down modeling and designing approaches are ongoing demand. This chapter overviews different mechanics, modeling techniques, and advanced engineering applications of 4D printing presented in this book as well as their significance.