This project by Niloofar Imani and her team, aims to design and fabricate a piece of auxetic furniture which its shape adapts to the user’s body figure using Rhino3d. In their study case, there is a higher level of dependency between design, structure, and material. Since the behavior of the chair and the right choice of material and geometry are interdependent, the design process started digitally.
Designers started by exploring different 2d patterns and their deformations, in order to achieve an auxetic behavior. The design has 3 main parts: rigid body, rigid joints, and elastic joints. The amount of elasticity of the flexible joints, size of the rigid body units and stiffness of the rigid joints were all parameters which needed to be taken into consideration in order to achieve the desired deformation.
Designers also did a rough deformation analysis with KIWI!3d ( grasshopper plugin) in order to have a better estimation of the expected deformation. However, the result was a fairly good start point to understand the behavior in a more tangible way, but they soon realized that physical prototyping was a better approach to anticipate and test the ideas than digital simulation.
Design team started prototyping in microscale and 1:1 scale in order to see the fabrication limitations, design potentials, and structural performance. They started experimenting with smaller scale components, using wood steaks as a rigid body, epoxy resin as rigid joints and tubes as elastic joints.
What was understood was that the epoxy resin connections are not strong enough and will break, and also in the flexible joints there should be a mechanism which guides the bending direction of the elastic part!
Then with a jump of scale to 1:1, a much better understanding of the deformation radius according to the elasticity and flexibility of the hinges was observed. It was also a given that a huge amount of spatial change was achieved with a minimum force. Although the first prototype with one 2D unit was not the design goal for the chair, it had the most spatial change.
Then the design team continued the prototyping process by connecting two units together in xy plane. The same amount of deformation freedom was achieved since the units were not constrained in 3D, so it was a more pleasant design. This prototype also demonstrated the spatial potential of creating positive and negative spaces. The rotation of the rigid elements in either divergent or convergent direction resulted in this behavior.
Although the bottom rigid elements are not perpendicular to the ground after deformation, the whole system is yet stiff and stable. Finally, the last prototype was produced as a proof of concept for scalability and various shape deformation. It consists of 4 cubic parts, which each acts perfectly as an individual unit!