Dutch university reports advances in thermoplastics processing

A doctoral student at the Universite of Twente has developed a method to detect 70 percent of the distortions and potential defects prior to production during the press-molding of thermoplastic composite parts.

The University of Twente's (Enschede, The Netherlands) Thermoplastic Composite Research Center (TPRC) reported on April 16 that it developed a method for detecting and preventing process-induced defects during the press-molding of thermoplastic composite parts.

Discoveries made by Sebastiaan Haanappel, a Ph.D. student at the University of Twente, could help make unexpected process-induced defects obsolete. Haanappel notes that, “We can now detect about 70 percent of the distortions and potential defects prior to the actual production process. Our results could lead to a massive breakthrough of this material in the automotive and aircraft industries.”

Haanappel investigated the effectiveness of computer simulations in predicting laminate deformations during the stamp-forming process. Dr René ten Thije from the AniForm Co. (a University of Twente spin-off company), who designs the software used for computer simulations, expects to have a user-friendly version ready for the market within a few months.

Haanappel used the AniForm simulation software to assess its predictive capabilities and to obtain an understanding of the deformation behaviour of the considered composite material. Agreement was found between the predictions of the model and the results obtained by forming experiments. Haanappel says that “70 percent of the deformations can be predicted by using the AniForm simulation software, provided that the behaviour of the material in question has been thoroughly characterized and described by the model. This also implies that it is possible to predict defects like wrinkling.”

Haanappel’s work has shown that forming simulation software has great potential for integration into the product development process. It allows for a relatively quick evaluation of modifications such as product geometry design, manufacturing process settings, and material configuration.

Process simulation tools allow for fast evaluation of the effects introduced by modifications of product design, production process and material configuration. Haanappel points out that “it is a big advantage to avoid trial and error in practice, which can be prohibitively expensive. Our aim is to lower the threshold of the application of thermoplastic composites, to be achieved by offering support to industry in terms of software, consultancy and advice.”

Haanappel's Ph.D. thesis entitled, “Forming of UD fibre-reinforced thermoplastics: a critical evaluation of intra-ply shear” is available on request from m.vanhillegersberg@utwente.nl