FAILURE INITIATION AND EFFECT OF DEFECTS IN STRUCTURAL DISCONTINUOUS FIBER COMPOSITES

摘要

Discontinuous Fiber Composites (DFC) molded by compression molding are increasingly beingused for structural parts of complex geometries. HexMC?, an advanced carbon/epoxy form ofDFC produced by Hexcel, was used for this study. It is used for structural parts in the newgeneration of commercial airplanes. DFC do not behave structurally like Continuous FiberComposites (CFC). These differences are driving the development of DFC specific designmethods, material allowable and design values. Some of the definitions for failure initiationdeveloped by the industry for CFC do not apply to DFC. Similarly, defects affecting CFC do notaffect DFC in the same way. This paper reports and discusses some of the findings about thedifferences in failure initiation and effect of defects between DFC and CFC. The need for a newapproach to non destructive testing, including pass/fail criteria are also discussed. Trial resultsusing Acoustic Emission, a potential non destructive technique for DFC, are also presented.