SEDL / STP / STP1439-EB / STP11319S

Degradation Parameters and Two-Stress Block Fatigue of Angle-Ply Carbon Fiber Reinforced Epoxy

Petermann, J
Graduate Research Assistants and Professor, Technical University Hamburg-Harburg, Polymers & Composites, Hamburg,

Hinz, S
Graduate Research Assistants and Professor, Technical University Hamburg-Harburg, Polymers & Composites, Hamburg,

Schulte, K
Graduate Research Assistants and Professor, Technical University Hamburg-Harburg, Polymers & Composites, Hamburg,

Pages: 12    Published: Jan 2005

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Abstract

Experimental studies on carbon/epoxy angle-ply laminates were conducted to prove different variables for their suitability as degradation parameters and to investigate frequency and load sequence effects. Within the investigated limits, the material did not behave in a frequency dependent manner. Although different damage mechanisms dominate at R = 0.1 and R = -1, the same degradation of fatigue strength per life decade was found. The variation of longitudinal stiffness and Poisson's ratio during fatigue life (the latter being considered superior to detect delaminations) exhibited load dependent characteristics. Under two-stress block fatigue, a significant effect of the load sequence on the fatigue life was found and different mechanisms were discussed.