Is it a bird, is it a plane – no, it’s a lightweight grand piano! Chris and Tim have spent most of their careers underwriting the structural integrity of safety critical components, providing consultancy services to the likes of Airbus and Rolls-Royce. You might think that there is little or no connection between aircraft wings or aero-engine fan blades and grand pianos – but that is where you would be wrong.
Structural engineers must constantly ask the same two questions: Is the structure strong enough? Is the structure stiff enough? And when the challenge of weight reduction is additionally posed, strength and stiffness become increasingly uneasy bedfellows.
The exam question set by Sarah and her vision for the ‘Standing Grand’ is not insignificant: replace the traditional cast iron frame & underlying timber framework with an assemblage of materials that reduces the weight of a typical grand piano by over a half. In short, design a portable acoustic grand!
With the weight target set, the question of strength can be resolved more straightforwardly by replacing the cast iron components with advanced lightweight materials, such as carbon fibre composites. The question of stiffness however requires a more sophisticated and subtle solution – the traditional box timber frame is replaced with an alternative and innovative structural configuration. In this regard, the Jigsaw ‘Smart Strut’ plays a key role not only in resisting the 20 to 30 tonnes or so of string tension, but more importantly as the keystone of a ‘world-first’ alternative piano structural arrangement and the manager of thermal mismatch – both crucial to keeping the piano in tune in all environments.