Journal of Material Sciences & Engineering

Composite C Springs for Anti-Seismic Building Suspension: Positioning Virtual Center of Pendulation above Gravity Center

Abstract

Max Sardou*, Patricia Sardou and Thomas Berg

Now that weight saving is mandatory, composite springs invented by SARDOU SA are the best choice for automotive suspensions, compared to steel. A Joint Venture called Sara was created in order to mass produce composite coils springs, with start of production in 2014 for AUDI. This has demonstrated that the viability of producing composite coil springs. This paper describes the benefits of composite ‘C’ springs and ‘S’ springs for high performance vehicle suspensions, spacecraft stage separation, and satellite orbital launching. Developing spacecraft stage separation for CNES (Centre National d’Etudes Spatiales) used the concept of ‘line of action’. Two springs are inclined in such a way that the resultant line of action cross at a virtual center well above the springs. This virtual center is above the top stage which provides stable and straight guidance. This spacecraft technology can be transferred to buildings by creating a ‘virtual center’ of pendulation positioned above the building center of gravity. This is achieved by using tilted composite springs oriented in such a way that their line of action converges creating this ‘virtual center’. Thanks to the ‘virtual center’ position, the building behaves as a pendulum, hanging from above. When an earthquake happens, the building will oscillate around its ‘virtual center’ and will go back safely to equilibrium after the tremor. ‘C’ springs, offering anti rust, anti-settlement, fail safe suspension with a virtual center is a must for long lasting protection of buildings against earthquakes.