Simulation engineering of polymeric prepreg composite systems

Abstract

High performance prepreg systems used in the airplane industry are proprietary and as a result, issues or problems concerning prepreg handling and composite performance have not been understood by the prepreg user and manufacturer. To help eliminate these proprietary concerns, model prepreg systems are typically used to understand commercial prepreg systems from neat resin through end-use. The usefulness of model prepreg systems is that they allow the resin components, fiber type/weave, and prepreg processing parameters to be changed to better understand their effects on prepreg and final composite characteristics. In this work, a prepreg system modeling methodology was developed that can be used to understand commercial prepreg systems and reduce the cycle time for new resin and prepreg system development and manufacturing. An engineering approach was used to develop the methodology by combining traditional analytical tools used by the chemist with bulk prepreg analytical methods. The methodology was based on the non-traditional viewpoint of designing for prepreg characteristics first, with cured mechanical properties being secondary. This change in paradigm is a logical progression for design when one considers that prepreg is the precursor to final composite parts. As a result, only by optimizing prepreg characteristics can composite manufacturing and final mechanical properties be optimized, ultimately adding value to the prepreg customer and manufacturer. The design of prepregs still must include the required final mechanical properties, however, it should be realized that this is only one part of many in the design of high performance prepreg systems. Therefore, by optimizing the resin chemistry for not only cured properties but also processing, the necessary quality for today's higher performance prepreg systems can be achieved. Collectively, the modeling methodology that was developed was used to investigate and understand several commercial prepreg systems from processing, structure, and property inter-relationships as they relate to the performance, design, and manufacturing of these materials.