Rupture of 3D-printed hyperelastic composites: Experiments and phase field fracture modeling

In this work, we study the failure behavior of 3D-printed polymer composites undergoing large deformations. Experimental results are compared to numerical simulations using the phase field fracture method with an energetic threshold and an efficient plane-stress formulation. The developed framework is applied to a composite system consisting of three stiff circular inclusions embedded into a soft matrix. In particular, we examine how geometrical parameters, such as the distances between inclusions and the length of initial notches, affect the failure pattern in the soft composites. We observe complex failure sequences including crack arrest and secondary crack initiation in the bulk material. Remarkably, our numerical simulations capture these essential features of the composite failure behavior and the numerical results are in good agreement with the experiments. We find that the performance of composites - their strength and toughness - can be tuned through selection of the inclusion position. We report, however, that the optimal inclusion spacing is not unique and depends also on the initial notch length. These findings offer useful insight for design of soft composite materials with enhanced performance. (C) 2020 Elsevier Ltd. All rights reserved.