*Article* **Investigation of Shear-Induced Deformation of Reinforcing Textiles by Optical Measurement Devices**

**Stefan Rothe 1,\*, Ellen Wendt 1, Sybille Krzywinski 1, Marianna Halász 2, Peter Bakonyi 2, Peter Tamás 3 and Attila Bojtos 3**


Received: 4 March 2019; Accepted: 25 March 2019; Published: 28 March 2019

**Abstract:** When fiber-reinforced plastic (FRP) components are designed, it is very important to ensure that textiles are formed into complex 3D geometries without folds, and that the reinforcing structure is oriented appropriately. Most research in this context is focused on finite element (FE) forming simulations and the required characterization of textile reinforcements. However, the early stage of the design of FRPs, where kinematic draping simulations are used, is barely considered. In particular, the need for a critical shear angle for the execution and evaluation of kinematic draping simulations is often neglected. This paper presents an extended picture frame test stand with an optical device recording shear-induced deformations with the help of a laser line emitter. Associated hardware and software for detecting and quantifying the fold formation during a picture frame test were developed. With the additional recorded information, a material-specific critical shear angle can be determined, material behaviors can be compared, and FE-based simulation methods can be evaluated. This innovative test stand and the associated software tools will help engineers to decide on suitable materials and improve transparency in the early stages of the design process.

**Keywords:** textiles; composite preforming; mechanical properties; shear behavior; surface analysis; picture frame test; kinematic draping simulation
