A new efficient and reliable algorithm to determine the fracture angle for Puck's 3D matrix failure criterion for UD composites

This work presents an enhanced method to accelerate the detection of inter-fibre fracture (IFF) in unidirectional fibre reinforced polymer composites. Subject of enhancement is Puck's IFF failure criterion for 3D stress states. To compute the IFF stress exposure, the orientation of the IFF fracture plane needs to be determined by a time consuming fracture angle search algorithm. In this work, the characteristics of occurring stress exposure over fracture angle curves are determined to find a reliable basis for accelerating the procedure of fracture angle search. Based on the obtained knowledge, a new, much more efficient search algorithm has been developed. Its performance and its significance are demonstrated by a finite element analysis of a cap-profile under 3-point bending. A previously existing enhanced fracture angle search algorithm is also evaluated, but found to be less reliable in predicting the correct fracture angle and corresponding stress exposure.