The technology of 3D printing is evolving rapidly enough to bring in a fourth dimension that is a result of shape shifting and would therefore allow printed objects to be load bearing. This innovation will be the force behind 3D printing in construction.

3D printers have become a standard fixture in many research laboratories – and now a select number of researchers are already looking to add yet another dimension to the technology: time. Kristina Shea, head of the Engineering Design and Computing Lab at ETH Zurich, is one of these scientists. 4D printing creates moveable and shape variable objects such as flat components that can be folded into three-dimensional objects at a later point, or even objects that can change their shape as a function of external influences.

Professor Shea and her group have now taken this approach one step further by developing a construction principle that allows them to control the deformation. "The flat structures we produce do not change their configuration randomly, but rather exactly in the way we design them," says Tian Chen, a doctoral student in Shea’s group. The structures can also support weight. The ETH scientists are the first to create these kinds of load-bearing 4D printed objects.

The structural principle depends on an actuating element developed by the scientists to take on two possible states: retracted or extended. The researchers combined these elements to create more complex structures. As the individual elements can assume only one of the two specific states, the researchers can predict the stable three-dimensional form of the overall structure. This also allows structures that can take on several stable forms. And as the researchers have also developed simulation software, they can predict accurately the shapes and the force that must be applied to produce the deformation. This helps them in the design of objects.

Read More