The FIBERS team identified actions in three domains that build on industry strengths and overcome barriers: reduction of materials costs, reduction of materials variability and development of new resins. Three-fourths of respondents prioritize alternatives to current carbon-fiber manufacturing techniques to lower its cost for new market segments, while 40 percent of respondents are proponents of a similar effort for glass fibers. Half of those surveyed advocate for designing material performance standards that enable the transition between alternate materials that are functionally equivalent. Material variability must be distinguished from processing variability. Prioritized actions for material variability include increasing consistency of material inputs and formats, as well as development of materials that facilitate defect reduction in composites.
Concerning the development of new resins, two-thirds of the respondents desire acceptance criteria specific to the composites industry, and a majority endorse the development of new and improvement of existing standards for composites component materials and for criteria specific to certain industry segments. More efficient and less expensive approaches to qualify composite materials, such as experimentation informed by modeling, should be pursued. Finally, though respondents did not prioritize recycling or other life-cycle materials issues, the issue was consistently raised as a looming concern among workshop participants, so research into new materials addressing environmental concerns should be pursued.
Innovations in Predictive Modeling Tools
Modeling tools are a valuable resource for investigating new composite designs and processing methods. These tools provide manufacturers a virtual environment to redesign existing processes or add new ones that can facilitate improvements in the manufacturing process. Unfortunately, these tools are often underutilized for such reasons as limited access to the tools, lack of qualified personnel with experience using them or lack of awareness that the tools even exist.
By linking the modeling of the manufacturing process to the models of in-service performance, manufacturers could use a virtual manufacturing environment to examine the benefits and consequences of such changes as material choices, processing conditions and capital equipment options before going down the long and expensive path of product and process development.
Currently, predictive modeling tools for composites fall into three categories: structural analysis, manufacturing process simulation and life-cycle analysis. The structural modeling tools for predicting part stiffnesses and completing stress analyses are relatively mature, but their use by SMEs has been limited for reasons cited previously. The modeling tools for process simulation, predicting in-service fatigue life and life-cycle inventory (LCI) are still emerging. LCI refers to examining the environmental impact of a composite product, and an LCI model can be used to quantify the energy use and material efficiency. Currently, life-cycle studies of composites lack the granularity needed to include major constituents found in thermosets and thermoplastics. As a result, designers and developers of composite products cannot easily use these tools. In addition, use of these tools is limited because only a small fraction of the constituent materials have been characterized to provide the needed inputs to these models, and many of those characterizations are incomplete.