A novel short-time concept for fatigue life estimation of carbon (CFRP) and metal/carbon fiber reinforced polymer (MCFRP)

For structural applications in the automotive and aircraft industries carbon fiber reinforced polymers (CFRP) have become increasingly important because of their outstanding strength-to-density ratio. A brittle failure behavior, poor damage tolerance and an insufficient level of electrical conductivity are drawbacks compared to monolithic metallic concepts which lead to a limited lightweight potential of composites. The integration of thin metal fibers as well as carbon fibers (MCFRP) is a promising new approach to advance the mechanical properties of conventional CFRP-structures. Structural components are subjected to cyclic loads during their lifetime. The fatigue behavior itself of both laminates - MCFRP and CFRP - was intensively investigated in Backe et al. [1]. The aim and novelty of the present study is a time- and resource-saving concept to analyze the fatigue behavior of composites. Therefore, the focus is on a new short-time procedure for fatigue life calculation of composites based on several cyclic load increase tests of each laminate. A clear correlation between experimental data of various constant amplitude tests with varied frequencies and calculated S-N curves is shown for MCFRP and CFRP laminates.