*Article* **Concepts for Increased Energy Dissipation in CFRP Composites Subjected to Impact Loading Conditions by Optimising Interlaminar Properties**

**Moritz Kuhtz 1,\*, Jonas Richter 1, Jens Wiegand 2, Albert Langkamp 1, Andreas Hornig <sup>1</sup> and Maik Gude <sup>1</sup>**


**Abstract:** Carbon fibre-reinforced plastics (CFRP) are predestined for use in high-performance components due to their superior specific mechanical properties. In addition, these materials have the advantage that the material properties and in particular, the failure behaviour can be adjusted. Fibre-dominated failure modes are usually brittle and catastrophic. In contrast, delaminations successively absorb energy and retain in-plane structural integrity. Previous investigations have shown that interface modifications can be used to selectively adjust the interlaminar properties, which decisively influence the delamination behaviour and the associated failure behaviour of structures. However, a systematic analysis of the influences of the positioning and characteristics of the interface modifications on the structural failure behaviour is still missing. Based on existing experimental investigations on the energy dissipation of CFRP impact-loaded beams, the failure behaviour is described here with the help of numerical simulations. The structural failure behaviour and the energy dissipation are represented in a three-dimensional, parameterised finite element analysis (FEA) model. Furthermore, the parameterised models are used to maximise the energy absorption of the three-point bending test through three concepts of interface modification. The large number of model input parameters requires a metamodel-based description of the correlation between the positioning and characteristics of the interface modification and the energy dissipation. Within the scope of the present work, a procedure is therefore developed which enables an efficient design of interface-modified CFRP under impact loads.

**Keywords:** carbon fibre-reinforced plastics; energy absorption; impact; optimisation; simulation; three-point bending test
