Quasi-Static Spring Rate Evaluation of Carbon Fiber Composite Coil Springs

This paper evaluates the stiffness response and other characteristics of carbon fiber reinforced plastic (CFRP) composite coil springs as fabricated by Pacific Concepts and Composites. In particular the effective static spring rates (K constants) are established under quasi-static testing regimes, and with the given geometry are found to range between 348 to 436 lbs/in. Material degradation is evaluated over repeated load/unload cycles and no material failure is evident under the specified loading. The performance of these coils is compared to alternative composite leaf and elliptical spring designs. This introductory study is based on mechanical testing to highlight the potential performance of such coils, to reintroduce this important topic to the community, and to establish that this is a viable and practical research topic.