A common trend in material research and development is hybrid composites—for good reason. While bulk materials are limited to their bulk properties, a smart combination of bulk materials can exceed these limitations by far. This is the case if there are multiple unrelated functions the material must fulfill. In this contribution, the authors focus on fiber metal laminates (FML) manufactured by a combination of deep drawing and thermoplastic resin transfer molding (T-RTM). Utilizing this process, hybrid laminates of woven glass fiber and steel sheets are manufactured. Expected benefits of the hybrid composite compared to its constituents are better impact and fatigue properties, which are well known and investigated for glass laminate aluminum reinforced epoxy (GLARE). Moreover, the hybrid T-RTM process leads to a higher freedom of design, lower cycle times in production, and better forming behavior compared to GLARE.
To simulate the deep drawing process, a draping simulation is implemented and applied . X-ray computed tomography is used to validate these results by acquiring volumetric images of a demonstrator part for the orientation analysis of draped fibers . Especially for woven fabrics, there are some challenges that have to be considered: First, samples must be sufficiently large to cover a region of interest that represents the surrounding woven fiber material. This requires a very robust orientation analysis, as the image resolution decreases with increasing sample size. Second, some orientation statistics (e.g., the orientation tensor of 2nd order) are not reasonable for this kind of structure. Thus, the main orientations of local orientation histograms are analyzed to calculate the shear angle of the fabric, which is a significant value for drape simulations.
We will show differences and unique solutions of orientation statistics by using orientation tensors, orientation histograms, and the derived principal orientations of both. Therefore, the volumetric data is processed by Volume Graphics VGSTUDIO MAX 3.3 to derive the abovementioned characteristics and map them on FE meshes to compare them directly with draping simulation results in a later step.
 Werner, H. O., Dörr, D., Henning, F., & Kärger, L. (2019, July). Numerical modeling of a hybrid forming process for three-dimensionally curved fiber-metal laminates. In AIP Conference Proceedings (Vol. 2113, No. 1, p. 020019). AIP Publishing.