Numerical modeling for shearing of unidirectional carbon fiber reinforced plastic laminates by means of near-net-shape blanking T. Stoel1,∗, L. Uhlmann1, F. Schweinshaupt1, M. Müller1, T. Herrig1, T. Bergs1,2 1 Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, 52074 Aachen, Germany 2 Fraunhofer Institute for Production Technology IPT, 52074 Aachen, Germany ∗ t.stoel@wzl-tf.rwth-aachen.de Keywords: Near-net-shape blanking, Carbon fiber reinforced plastic, Shearing process model. Structural components made of carbon fiber reinforced plastic (CFRP) produced using near-netshape molding processes exhibit a high degree of lightweight suitability. In order to fulfill geometric and functional requirements, a finishing process step of outer and inner contours is necessary for CFRP structural components. Near-net-shape blanking processes with small die clearance and high blank holder force show potential for economical finishing of CFRP structural components with high blanked part quality [1]. For the knowledge-based design of a near-net-shape blanking process comparable to fine blanking with a small die clearance and superimposed blank holder and counter force, an understanding of the separation mechanisms during shearing of CFRP laminates is required. Therefore, this paper deals with the development of a finite element (FE) process model for near-net-shape blanking of unidirectional (UD) CFRP laminates with different fiber volume fraction. Material modeling of the UD CFRP laminates was carried out by means of experimental characterization based on tensile, compression, shear and delamination tests. The formulation of the material model was implemented using a VUMAT user subroutine and includes four damage modes for fiber and matrix under tensile and compressive loading [2]. Regarding the damage initiation condition, the Hashin criterion was used for the fiber and the Puck criterion for the matrix [3]. The application of the blank holder and counter force was realized using a kinematic model based on a VUAMP user subroutine, which is closed loop controlled by the respective reaction force and thus enables an accurate and numerically stable force application. Numerical analysis on near-net-shape blanking of UD CFRP laminates with different fiber volume fraction showed that the blanking force is affected by the fiber-orthogonal longitudinal shear strength. With increasing fiber volume fraction, an increase in blanking force is to be expected. A validation based on experimental near-net-shape blanking tests, which will be conducted in the next step, enables an analysis to understand the separation mechanisms by means of the damage criteria of fiber and matrix in UD CFRP laminates. References [1] Klocke F., Shirobokov A., Kerchnawe S. et al. (2017). Experimental Investigation of the Hole Accuracy, Delamination, and Cutting Force in Piercing of Carbon Fiber Reinforced Plastics. Procedia CIRP, 66, 215-220. [2] Shirobokov A., Klocke F., Baer O. et al. (2018). Finite element modelling of cutting force in shearing of multidirectional carbon fibre reinforced plastic laminates. Journal of Composite Materials, 52, 3865-3874. [3] Phadnis V. A., Makhdum F., Roy A. et al. (2013). Drilling in carbon/epoxy composites: Ex83
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