Variable forming tool and process for thermoset prepregs with simulation verified part quality

Variable forming tool and process for thermoset prepregs with simulation verified part quality

Kategorien Konferenz (reviewed)
Jahr 2014
Autoren Hundt. T., Schmidt, C., Denkena, B., Engel, K., Horst, P.:
Veröffentlicht in ESAFORM 2014, Selected, peer reviewed papers from the 17th Conference of the European Scientific Association on Material Forming, May 7-9, Espoo, Finnland, S. 391-398.

In this paper a new variable forming tool concept and associated numerical methods for calculating optimal actuator layout and estimating CFRP part quality are presented. The concept of the tool features a modular design and aetive control of the forming process to aehieve the desired geometry. Initially the laminate is plaeed on the flat top layer of the fonning tool. There it is fixed and compacted using vacuum bagging. After compaeting, it is heated up to increase the perfonnance of the fonning process using water based tempering of the forming tool's top layer. The heated laminate is then fonned, pulling the tool's top layer into the desired geometry using the actuators. Finally, the fonned laminate is cooled and transferred into a mold for curing. The position of the forming tool's aetuators on the base plates is variable. Numerical optimization in combination with finite element (FE) technologies is utilized, to approximate the tool surfaee within given error margins, with as few aetuators as possible. In addition, results of a numerical method for part quality estimation are shown. The influence of the fonning process on mechanical properties due to fiber waviness is taking into account using a self-developed method that includes manufaeturing charaeteristics in FE modeling of the part. The method is based on mathematical descriptions of fiber waviness, which are implemented into a FE model. Therefore a structure discretization assuming perfect fiber orientations is realized and the expected fiber waviness induced by the forming process is applied element-wise.