Structures support life. Without structures, we would just have random heaps of parts. At the beginning of the design process we should ask three questions about a structure:

• Why do we need it?
• How long should it last?
• What should it look like?

The answers to these three questions describe the purpose, dictate the material, and define the form of a structure. The primary requirement of a structure is that it should support the other components of a system and so we are focussing on structural integrity, which means making sure a structure has the appropriate stiffness and strength. We have said that if it meets this primary requirement and is also aesthetic, cheap with a tiny ecological footprint and fits beautifully into its cultural and social context then it is a ‘super’ structure. In other words, it must have durability, utility and beauty.

We have made a start on structural integrity by looking at how forces flow through a structure and we have started to use free-body diagrams as simple representations of the forces acting on a component of a structure. Newton’s First Law can be used to perform detailed analysis of the forces and evaluate unknown ones.

Finally, we have explored two classes of elegant structure: minimum energy structures and tensegrity structures. You could describe one as lazy and the other as highly strung!

What’s next?

Next week, the focus will be on freedom and energy: degrees of freedom and strain energy. We’ll extend this week’s discussion on domes to egg shells and continue the laziness theme by exploring bubbles and bats’ wings. I hope you’ll join us.