Stanley A. Iobst

Modeling Flow in Compression Resin Transfer Molding for Manufacturing of Complex Lightweight High-Performance Automotive Parts

Lightweight vehicles for energy savings encourages the use of composites in the new generation of vehicles. The compression resin transfer molding process (CRTM) is a novel variation of liquid composite molding (LCM) which offers fast manufacturing cycle for net-shape complex parts with excellent performance, ideal for the automotive industry. The process combines features of resin transfer molding (RTM) and compression molding. The process stages are identified and compared to other LCM processes to take advantage of existing simulation tools. A numerical model that simulates the resin flow in this process is proposed. Several first-order analyses are developed to estimate important process parameters to simplify modeling. Finally, this approach is used to model and simulate the process and is applied to a complex automotive part (the Automotive Composites Consortium B-pillar) with qualitative experimental validation.

Thermomechanical behavior and structure of poly(vinyl chloride)

Abstract Both static and dynamic thermomechanical techniques have proved to be useful in elucidating effects of molecular structure and morphology on the behavior of poly(vinyl chloride). Indeed, such methods are sometimes sensitive to rather small differences in, for example, crystallinity. In this paper, the current literature is reviewed, with emphasis on the relation between stereoregularity, crystallinity, and mechanical relaxation behavior. In order to interpret results of recent studies, simple models are then proposed for the typical morphologies encountered. Most experimental facts are consistent with the existence of very small plate-like crystallites, with intercrystallite spacings being inversely dependent on crystallinity, and, in turn, inversely dependent on polymerization temperature.