Dimensional Stability and Variance of Carbon Fiber Reinforced Plastics – Current State and Necessary Future Developments

Because of the advantage of the specific properties of CFRPs compared to metals, these materials are used in several industrial sectors from mechanical engineering, energy engineering over aerospace to manufactures of sports equipment. Common to all these fields of application is a relative low volume and a high amount of manual production. This is equivalent to the current use of CFRPs in the automotive industry, which mainly concentrates on small volume productions of sports cars or electric vehicles.If CFRPs should find their way into higher volume productions, an automated production and assembly process must be ensured. Therefore a profound knowledge about the dimensional stability of single parts and assemblies is required. Most of the scientific publications however deal with the deviation of the actual geometry compared to the nominal geometry and the resulting measures to correct production process. Therefore different methods exist to approximately quantify the dimensional stability of parts made of CFRPs. One solution is to conduct FE-analysis (finite element analysis) which simulates the properties and interaction of different layers and materials of a part [1], . A second solution is according to Dong [2] the abstraction of the geometry in fast solvable analytic formulas.The variance of the results is not under a comparable attention although Bohn [3] worked out the importance of dimensional management for the automotive industry and the variations even within one material system. Changing this system, especially towards CFRPs, raises the complexity as there are is up to now much less experience in the automotive industry.